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Amylase
Introduction
Amylase is a digestive enzyme predominantly secreted by the pancreas and salivary glands and is present in other tissues at minimal levels.[1] Amylase was initially described in the early 1800s and is one of the pioneering enzymes to undergo scientific investigation. Although this enzyme was originally termed diastaste, it was later renamed "amylase" in the early 20th century.[2]
The primary role of amylases is to break down the glycosidic bonds within starch molecules, transforming complex carbohydrates into simpler sugars. Amylase enzymes are categorized into 3 main classes—alpha-, beta-, and gamma amylases—each targeting distinct segments of the carbohydrate molecule.[2] Alpha amylase is present in humans, animals, plants, and microbes, whereas beta amylase is primarily found in microbes and plants. Gamma amylase, on the other hand, can be located in both animals and plants.[3]
In 1908, a study by Wohlgemuth identified the presence of amylase in urine, paving the way for its application as a diagnostic laboratory test. Amylase is a frequently ordered standard diagnostic test, often combined with lipase, particularly when acute pancreatitis is suspected in patients.[2]
Etiology and Epidemiology
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Etiology and Epidemiology
Elevated amylase levels may manifest in various conditions, including pancreatic, salivary, and intestinal diseases, as well as decreased metabolic clearance and macroamylasemia.[4] Approximately 11% to 13% of patients experiencing non-pancreatic abdominal pain exhibit elevated pancreatic enzyme levels.[5] On at least one occasion, 60% of asymptomatic HIV-positive patients displayed abnormal amylase or lipase measurements.[6] Upon admission, 26 out of 208 patients (12.5%) with acute abdominal pain unrelated to pancreatic issues presented with elevated serum amylase levels.[5]
Abnormally elevated amylase levels are observed in 35% of patients with liver disease.[7] Furthermore, elevated amylase levels are found in around 16% to 25% of diabetic ketoacidosis cases.[8][9] In a group of 74 patients with surgically resectable lung cancer, 13 showed hyperamylasemia.[10]
Pathophysiology
Amylase is a heterogeneous calcium-dependent metalloenzyme with a diverse molecular weight range, typically between 54 and 62 kDa. The compact size of amylase facilitates efficient filtration through the glomeruli.[1] Amylase is eliminated through both the renal system and the reticuloendothelial system.[3] This enzyme exists as 2 isoenzymes—pancreatic (P-type) and nonpancreatic (S-type)—which are products of 2 closely linked loci on chromosome 1. Additional amylase heterogeneity results from allelic variation, with 12 alleles for the S-type and 6 alleles for the P-type.[11] Both types of amylase also undergo post-translational modifications involving deamidation, glycosylation, and deglycosylation, giving rise to various isoforms. Amylase exhibits a broad tissue distribution, with the most significant levels of P- and S-type activities being found in the exocrine pancreas and salivary glands, respectively.[12]
P-type amylase is synthesized by pancreatic acinar cells and released into the intestinal tract through the pancreatic duct system. The enzymatic activity of P-type amylase is optimized under the slightly alkaline conditions of the duodenum.[13] Meanwhile, the salivary glands host the highest S-type amylase activity, initiating starch hydrolysis during mastication in the mouth and the passage through the esophagus. However, this action is terminated upon exposure to stomach acid.
S-type amylase is also detectable in extracts from testes, ovaries, fallopian tubes, Mullerian ducts, striated muscle, lungs, and adipose tissue, as well as in bodily fluids such as semen, colostrum, tears, and milk. Approximately 25% of plasma amylase is excreted by the kidneys, with the majority being reabsorbed within the proximal tubules.[14] The liver is believed to be the primary organ responsible for amylase elimination, leading to a half-life of approximately 10 hours. Serum amylase is intricately controlled within the body,[15] with a delicate balance between its production and clearance rates. Elevated amylase levels can result from heightened production, whether originating in the pancreas or outside it, or from a diminished clearance rate.
Genetic regulation is likely to play a crucial role in the preliminary determination of salivary amylase.[1] In newborns, the predominant amylase isozymes detected in urine originate from saliva, and as development progresses, both salivary and pancreatic amylase isozymes become more prominent. The functional integrity of amylase is entirely dependent on the presence of calcium.[16] However, complete functionality is achieved only in the presence of specific anions, including chloride, bromide, nitrate, or monohydrogen phosphate. Chloride and bromide are the most effective activators. The pH optimum for amylase activity falls within the range of 6.9 to 7.0.[17]
The analyte amylase is an endoglycosidase enzyme belonging to the hydrolase class, and it catalyzes the hydrolysis of 1,4-α-glucosidic linkages between adjacent glucose units in complex carbohydrates.[18] Notably, straight-chain (linear) polyglucans, such as amylose, and branched-chain polyglucans, such as amylopectin and glycogen, are hydrolyzed at different rates.[19] In the case of amylose, the enzyme cleaves the chains at alternate α-1,4-hemiacetal (-C-O-C-) links, thereby forming maltose and some residual glucose. In the case of branched polyglucans, the enzyme generates maltose, glucose, and a residue of limit dextrins. Notably, the enzyme does not target the α-1,6-linkages at the branch points.[2]
Specimen Requirements and Procedure
Either serum or heparinized plasma can serve as suitable samples. Nevertheless, a particular study indicated that when using dry-film technology for measurement, heparinized plasma samples yielded significantly higher results than serum samples.[20] As amylase has an absolute requirement for calcium ions, it is noteworthy that chelating anticoagulants, such as citrate, oxalate, and EDTA, cannot be used when collecting plasma for amylase measurements. However, urine specimens without preservatives, obtained through random or timed collections, are considered valid samples.
Amylase is occasionally measured in ascitic, peritoneal, or pleural fluid, and its presence in these fluids can suggest pancreatitis or the presence of a tumor. In serum, amylase activity remains stable for up to 4 days at room temperature, 2 weeks at 5 °C, 1 year at −28 °C, or 5 years at −75 °C. Urine specimens should be analyzed within 12 hours at room temperature or within 5 days when stored at 5 °C. Notably, urine should not be subjected to freezing.[21]
Diagnostic Tests
Over the years, amylase has played a central role in diagnosing acute pancreatitis. Amylase can be assessed through either a blood test or a urine test. In the case of a urine test, it can be conducted through a clean catch or a 24-hour urine collection.[3] The normal range for serum amylase can vary between different laboratories. Notably, it is clinically significant to differentiate pancreatic amylase from other amylase isoforms. If amylase levels are elevated while lipase remains within the normal range, it might indicate an issue originating outside the pancreas.[15]
The lipase-to-amylase ratio may help distinguish between gallstone-induced pancreatitis and alcoholic pancreatitis. Gallstones tend to cause more significant elevations in amylase levels, whereas alcohol typically results in higher elevations in lipase levels. A lipase-to-amylase ratio exceeding 2 exhibits 91% sensitivity and 76% specificity for diagnosing alcoholic pancreatitis, whereas a ratio exceeding 5 demonstrates 31% sensitivity and nearly 100% specificity for identifying alcoholic pancreatitis.[22] Elevated alanine transaminase levels reaching 3 times the normal range are highly specific for diagnosing gallstone pancreatitis. Although the combined measurement of serum amylase and lipase enhances specificity compared to either test in isolation, it does not notably improve sensitivity.[23]
Testing Procedures
The amylase test is conducted using semiautomatic or fully automated analyzers that operate on the principles of photometry. Photometry entails the measurement of light absorption across the ultraviolet (UV), visible (VIS), and infrared (IR) spectrum. This measurement is used to quantify the concentration of an analyte in a solution or liquid. Photometers utilize a specific light source and detectors, such as photodiodes, photoresistors, or photomultipliers, to transform the light transmitted through a sample solution into a corresponding electrical signal. Photometry applies Beer–Lambert law to calculate coefficients obtained from the transmittance measurement.[24] A test-specific calibration process is utilized to establish a correlation between the absorbance and analyte concentration to achieve highly accurate measurements.[25]
P-type amylase can be differentiated from S-type amylase by selective inhibition of S-type using a wheat germ inhibitor, temperature inhibition, immunoprecipitation, or immunoinhibition with a monoclonal antibody. However, only the methods based on selective inhibition by monoclonal antibodies have demonstrated adequate precision, reliability, practicality, and analytical speed, enabling the reliable measurement of P-type amylase.[26] The amylase isoforms can be separated by isoelectric focusing, ion-exchange chromatography, or gel/capillary electrophoresis by electrophoretic endosmosis.[27]
Interfering Factors
Amylase assays typically resist hemoglobin, bilirubin, or triglyceride interference. However, collecting specimens in tubes containing oxalate, citrate, or EDTA may result in falsely decreased values due to the chelation of necessary amylase cofactors.[3] Certain medications, such as aspirin, morphine, antiretrovirals, and estrogen-containing drugs, can potentially affect serum amylase levels.[28]
Elevated amylase activity in serum can be attributed to a condition known as macroamylasaemia, which is characterized by the formation of macromolecular complexes. These complexes typically involve immunoglobulins— predominantly IgA or IgG—although self-polymerization or association with other proteins can also occur.[29] Typically, these complexes maintain their enzymatic activity but cannot be effectively filtered by the renal glomeruli. As a result, this condition leads to delayed clearance and increased serum amylase activity.[30] This benign condition has been reported in up to 1.5% of hospitalized patients, accounting for as much as 28% of chronic and otherwise unexplained hyperamylasemia cases.[31]
Macroamylasaemia is a condition associated with autoimmunity, malignancy, cardiovascular disease, diabetes mellitus, and malabsorptive disorders. Macroamylasemia should be considered when evaluating asymptomatic patients with elevated serum amylase levels.[32] Notably, no specific treatment is mandated for this condition, as it is typically benign.[33]
The circulating pancreatic amylase levels are higher in female subjects with O blood type than those with A blood type, where pancreatic amylase levels tend to be lower.[34] Psychosocial stress contributes to elevated salivary amylase levels even in healthy individuals, potentially resulting in higher total serum amylase. However, it remains unconfirmed through clinical studies whether psychosocial stress has a long-term effect on serum amylase levels.[35]
In pancreatitis accompanied by hypertriglyceridemia cases, serum amylase levels may mistakenly appear within the normal range. This discrepancy is linked to an inhibitor associated with elevated triglycerides, which interferes with the assay for the enzyme. By diluting the serum, the inhibitory effect can be lessened, allowing for a recalculation of serum amylase levels to reveal the actual concentration.[36]
Results, Reporting, and Critical Findings
The reference intervals for amylase can vary among different assay methods due to variations in the substrates used and reagent preparations.[37] A patient's blood test values should be interpreted based on the reference values established by the specific laboratory conducting the test. Furthermore, it is recommended for each laboratory to establish its unique reference interval based on its specific testing methodology.[38] A significant proportion of subjects of African and Asian origin exhibit S-type amylase activity levels exceeding the reference interval established for white populations. This can lead to an elevated total amylase measurement without indicating any pathological condition.[39]
The blood amylase activity in newborns is approximately 18% of that in adults. Serum amylase activity does not show significant differences between males and females. In healthy adults, P-AMY typically accounts for about 40% to 50% of the total amylase activity in serum. In most children less than 6 months of age, serum P-AMY activity is not detectable. However, its activity gradually increases after this period and reaches adult concentrations by the age of 5, which corresponds to the postnatal development of exocrine pancreatic function.[40] Therefore, using this enzyme for diagnosing acute pancreatitis in young children should be avoided.[41]
Currently, there is no internationally standardized reference range for amylase levels, with the reference range varying from as low as 20 U/L to as high as 300 U/L. However, elevated amylase levels exceeding 3 times the upper limit of normal (URL) strongly indicate the likelihood of acute pancreatitis.[42] Amylase levels below this threshold are associated with other medical conditions. Abnormally low amylase levels, while less common, can be observed in conditions such as cystic fibrosis, chronic pancreatitis, diabetes mellitus, obesity, and among individuals who smoke.[43] Clinicians should be aware of such potential causes when interpreting low amylase activity in patients.[44]
A finding of persistently elevated total amylase and normal lipase should raise the possibility of macroamylasemia. Screening tests such as the amylase creatinine clearance ratio (ACCR) or polyethylene glycol precipitation can be valuable in identifying macroamylase.[45] ACCR can be easily calculated from paired random urine and serum amylase and creatinine measurements. Although an ACCR lower than 1% indicates the possibility of macroamylasemia, each laboratory needs to assess the suitability of these expected values for its unique patient population and, if required, establish its own reference ranges.[46] An ACCR value greater than 5% suggests acute pancreatitis.[47] Notably, the ACCR is also known to be increased in diabetic ketoacidosis, renal disease, and after surgical procedures.[48]
Clinical Significance
Amylase is primarily used for diagnosing pancreatic diseases and is a frequently measured enzyme owing to the accessibility of cost-effective and readily automated methods. Although amylase is a sensitive marker for acute pancreatitis, its lack of specificity is evident, as it can be elevated in numerous conditions unrelated to the pancreas.[49] Pancreatitis can be defined by the presence of at least 2 out of the 3 criteria—abdominal pain, serum amylase, and/or lipase levels—exceeding 3 times the URL and characteristic findings of pancreatitis on abdominal imaging. Therefore, the clinical significance of amylase has been a subject of inquiry.[50] In cases of elevated amylase levels and insufficient evidence of pancreatitis, healthcare professionals should contemplate alternative causes of hyperamylasemia.[51]
Amylase does not help predict the severity of an acute pancreatic episode or for monitoring the condition. The magnitude of the increase in serum enzyme activity is not correlated with the severity of pancreatic involvement. However, a more substantial rise in amylase levels does increase the probability of acute pancreatitis. The limited specificity of total amylase measurement has spurred interest in directly measuring P-type amylase, rather than total enzyme activity, for the differential diagnosis of patients experiencing acute abdominal pain.[19] Utilizing the best decision limit, which corresponds to an activity 3 times the URL, the specificity of P-type amylase in diagnosing acute pancreatitis exceeds 90%. Furthermore, P-AMY significantly enhances sensitivity in the late detection of this condition. One week after onset, P-type amylase values remain elevated in 80% of patients with uncomplicated pancreatitis, while only 30% still exhibit increased total amylase activity.[52] This long-standing increase in P-type amylase activity in serum renders the traditional measurement of total amylase in urine redundant. This test is performed to achieve better diagnostic sensitivity in the late phase of pancreatitis.[53]
Amylase inhibitors such as acarbose have been used in treating type 2 diabetes and have demonstrated the ability to lower hemoglobin A1C levels and reduce peak postprandial glucose. Acarbose has also proven effective in enhancing the remission of dumping syndrome in patients who have undergone bariatric procedures. In addition, this drug has demonstrated the capacity to reduce the risk of cardiovascular disease by slowing the progression of carotid artery thickening.[54] Elevated amylase levels can be observed in a wide array of conditions. Therefore, clinicians need to follow a well-defined, systematic approach when hyperamylasemia is detected. This approach can prevent unnecessary hospitalization and ensure timely and appropriate treatment.[55] Biliary tract diseases, including cholecystitis, can lead to up to a 4-fold increase in serum P-type amylase activity due to primary or secondary pancreatic involvement.[56]
Various intra-abdominal events can result in a substantial rise in serum P-type amylase activities, often reaching up to 4-fold or even greater. These elevations may be attributed to the leakage of P-type amylase from the intestine into the peritoneal cavity and subsequently into the circulation.[57] In cases of renal insufficiency, serum amylase activity increases proportionally with the degree of renal impairment, typically not exceeding 5 times the URL.[58]
Cases of amylase-producing multiple myeloma have been described. Increased amylase activity in most patients results from salivary-type hyperamylasemia—sialyl salivary type.[59] A common feature of the myeloma cell lines associated with hyperamylasemia is the presence of a chromosome 1 translocation, which harbors the gene for amylase. The link does not seem to be specific to any particular immunoglobulin class. The onset of hyperamylasemia is reported to be associated with rapid disease progression, extensive bone destruction, and increased mortality. Consequently, serum amylase activity may serve as a valuable prognostic "tumor marker" in patients with multiple myeloma, with activity decreasing in response to treatment and increasing during periods of relapse.[60][61] The amylase isoenzyme in cases of ruptured ectopic pregnancy is not well characterized. In severe cases that are diagnosed late, the elevated isoenzyme may be P-AMY due to pancreatic involvement associated with peritonitis, despite the presence of S-AMY in the fallopian tube.[62]
In some cases, patients with pheochromocytoma or paraganglioma exhibit hyperamylasemia, usually the salivary isotype. In these instances, hyperamylasemia might be associated with a hypertensive crisis and vasoconstriction, resulting in tissue hypoxia rather than being a consequence of tumor secretion. This elevation in amylase activity is often transient.[63] Salivary-type hyperamylasemia has been documented in various conditions unrelated to salivary gland disorders. These include diabetic ketoacidosis, pneumonia, and postoperative states following a diverse array of surgical procedures, including extra abdominal procedures such as postcoronary bypass.[64]
Benign pancreatic hyperenzymemia or Gullo syndrome was first described by Lucio Gullo and is characterized by elevated serum levels of amylase, pancreatic isoamylase, lipase, and trypsin activities in asymptomatic individuals with no evidence of pancreatic disease on imaging. The syndrome occurs sporadically or in a familial form, and amylase activity may exhibit notable fluctuations, occasionally normalizing transiently in some cases.[65] The etiology of benign pancreatic hyperenzymemia does not appear to involve CFTR, SPINK1, or PRSS1 gene mutations. In addition, this condition cannot be attributed to mutations in genes known to be associated with pancreatitis or other PRSS1/SPINK1 genes.[66] Researchers discovered that approximately one-third of patients with chronic non-pathological pancreatic hyperenzymemia had notably elevated fecal calprotectin concentrations. They recommended investigating this discovery to explore the potential connection between intestinal ecology and alterations in pancreatic enzymes.[67]
Damage of salivary glands, leading to salivary hyperamylasemia, has been observed following trauma or surgical procedures on the salivary gland. Furthermore, radiation to the neck area involving the parotid gland can lead to duct obstruction or calculi formation in the salivary glands.[14] Chronic alcoholism and anorexia nervosa can also lead to subclinical damage to the salivary glands. In individuals with alcoholism, 10% of patients exhibit salivary amylase activity, which is 3 times higher than normal and may be associated with chronic liver disease.[68]
Hyperamylasemia in anorexia nervosa is associated with vomiting, and the detection of elevated salivary amylase levels may hint at concealed vomiting.[69] However, pancreatitis can develop in these patients, especially during the refeeding process. Therefore, it may be warranted to measure plasma lipase and/or amylase isoenzymes to distinguish between pancreatitis and salivary hyperamylasemia.[70]
Hyperamylasemia may be associated with various tumors, either due to ectopic production of the enzyme by the tumors or possibly as an inflammatory response by the tumor cells, thereby leading to the significant release of the enzyme normally produced in these tissues into the bloodstream.[71] The raised isoenzyme is almost exclusively salivary type in ovarian, lung cancer, multiple myeloma, and pheochromocytoma.[72] Amylase-producing tumors of the lung are rare, accounting for only 1% to 3% of all lung carcinomas, and in such instances, the salivary amylase isotype is typically present. These amylase-producing lung carcinomas are primarily adenocarcinomas, although hyperamylasemia has also been documented in cases of small-cell carcinoma.[73] Amylase activity has been suggested as a valuable tumor marker for monitoring the patient's treatment in amylase-producing lung carcinoma cases.[74] In one study, it was noted that 39% of patients with ovarian carcinoma exhibited hyperamylasemia, primarily of the salivary type, suggesting that salivary amylase could be a useful indicator for assessing the effectiveness of radiotherapy in this context.[75]
Gut diseases, including mucosal inflammatory disease of the small intestine, mesenteric infarction, intestinal obstruction, appendicitis, and peritonitis, generally lead to elevated P-type isoamylase levels due to increased absorption of amylase from the intestinal lumen.[76] Gut perforation is associated with the leakage of intestinal contents into the peritoneum, leading to inflammation and the absorption of amylase across the inflamed peritoneum, which can result in hyperamylasemia. Acidosis can lead to hyperamylasemia and may arise from 2 sources—ketoacidosis, which results in increased S-type and P-type isoamylases, or nonketotic acidosis, which leads to increased S-type isoamylase.[77] Postoperative amylase increases can lead to elevated S-type and P-type isoamylase levels, with a more common increase observed in salivary amylase.[78] This elevation may occur after procedures involving extracorporeal circulation or nonabdominal surgery. For instance, approximately 30% of patients undergoing cardiac surgery exhibit elevated S-type isoamylase.[79]
Rare cases of hyperamylasemia have been reported in association with systemic lupus erythematosus, as well as with ciprofloxacin treatment.[80] Additional causes contributing to hyperamylasemia include pneumonia (increased salivary amylase), cerebral trauma, burns, abdominal aortic aneurysms (increased pancreatic amylase), drugs (increased salivary and/or pancreatic amylase), anorexia nervosa and bulimia (increased salivary amylase), non-pathological factors (increased salivary and/or pancreatic amylase), and organophosphate poisoning. Post-procedure balloon-assisted enteroscopy has also been associated with elevated amylase levels. Therefore, it is recommended to measure pancreatic amylase levels rather than total amylase levels following these procedures.[3][81] Elevated pancreatic enzymes can be found in critically injured trauma patients, even in the absence of true pancreatitis.[82]
Quality Control and Lab Safety
The purpose of a clinical laboratory test is to assess the pathophysiological state of a specific patient, aiding in the process of diagnosis, offering guidance or supervision of treatment, and evaluating the likelihood or advancement of the disease.[83] Implementing a quality management system (QMS) is paramount in upholding the precision and reliability of laboratory tests.[84] Internal quality control (IQC) is a cornerstone within the QMS of a clinical laboratory, systematically monitoring and verifying the accuracy and precision of laboratory test results.[85]
All aspects of laboratory operation, including IQC, must adhere to written standard operating procedures (SOPs).[86] The SOP for quality control (QC) should include all aspects of the program, including the selection of QC materials, determination of statistical parameters to describe method performance, criteria for accepting QC results, measurement frequency of QC materials, corrective actions when problems arise, and the documentation and review processes. The SOP should specify authorized personnel responsible for setting acceptable control limits and interpretive rules for result release, reviewing performance parameters, including statistical QC results, and granting authorization for exceptions to or modifications of established QC policies and procedures.[87]
The QC samples are periodically measured using the same method as clinical samples, and the results are analyzed to ensure that the measurement procedure meets performance requirements suitable for patient care.[85] If the QC result falls within the acceptable limits of the known value, it verifies that the measurement procedure is stable and performing as expected. This indicates that results for patient samples can be reported with a high probability that they are suitable for clinical use. If a QC result falls outside the acceptable limits, it indicates that the measurement procedure is not performing correctly. As a result, patient sample results cannot be reported, and corrective action is necessary. After taking corrective measures, patient sample measurements are repeated, along with QC samples, to ensure accurate and reliable results.[88] Adhering to good laboratory practice involves verifying that a method is performing correctly at the moment when patient results are being measured.[89]
For non-waived tests, laboratory regulations mandate the analysis of a minimum of 2 control material levels at least once every 24 hours. In cases where it is necessary, laboratories may choose to assay QC samples more frequently to ensure the accuracy of results. In addition, it is essential to analyze QC samples after the calibration or maintenance of an analyzer to verify the correct method performance.[85] To reduce the frequency of QC testing for assays that have manufacturer-recommended intervals less frequent than those required by regulatory agencies, such as once per month, laboratories have the option to implement an individualized QC plan (IQCP). This plan includes a risk assessment, which evaluates potential sources of errors across all testing phases, and the implementation of a tailored QC strategy to minimize the risk of errors.[90] Westgard multi-rules are used to assess the QC runs. In case of a rule violation, appropriate corrective and preventive actions must be executed before patient testing.[91]
Proficiency testing (PT) is a program designed to assess method performance by comparing results with those from other laboratories analyzing the same set of samples.[92] PT providers distribute a set of samples among a group of laboratories for this purpose. Each laboratory analyzes the PT samples in the same manner as they would with patient samples and then reports the results to the PT provider for evaluation. The PT provider assigns a target value to the samples and evaluates whether the individual laboratory's results align closely with the target value, indicating acceptable method performance.[93] The acceptable performance criteria for amylase assay, as defined by the Clinical Laboratory Improvement Amendments (CLIA) and College of American Pathologists (CAP) proficiency program, are within ±30% of the mean value of laboratory peer groups.[94]
If an unacceptable PT result is identified, the method must be investigated for possible causes, and any necessary corrective action must be taken.[95] Furthermore, even when a PT result is within acceptability criteria, it is good laboratory practice to investigate PT results that deviate by more than approximately 2.5 standard deviation index (SDI) from the peer group mean. When the SDI is 2.5, there is only a 0.6% probability that the result will fall within the expected distribution for the peer group. Therefore, it is reasonable to suspect that a method problem may need to be corrected.[96] Investigative steps, reviewed data, and conclusions derived from the review must be documented in a written report of the unacceptable PT result, which the Director of the laboratory should review.[93]
Ensuring lab safety is paramount in clinical laboratories, where precise and reliable results are essential for patient diagnoses and treatment plans.[97] Maintaining a secure environment requires strict adherence to safety protocols. This includes using personal protective equipment (PPE), including lab coats, gloves, goggles, and masks, to protect against potential hazards.[98] Chemical safety measures include appropriate labeling, storage, and handling of chemicals, ensuring that hazardous substances are stored in designated areas. Similarly, biological safety is of utmost importance, requiring the use of biosafety cabinets and stringent protocols for managing potentially infectious materials. Regular maintenance and calibration of equipment, as well as staff training on safe operation, are crucial in preventing accidents and ensuring accurate results. In case of emergencies, it is essential to have well-defined procedures for handling accidents, spills, or exposures, along with a clear understanding of the locations of safety equipment and evacuation routes.[99]
Fire safety precautions, including the availability of fire extinguishers and proper storage of flammable materials, are of utmost importance. In addition, electrical safety measures, such as equipment maintenance and ensuring proper grounding, help prevent electrical hazards.[100] Safe handling and disposal of sharps and appropriate management of chemical and biohazardous waste are essential to protect lab personnel. Rigorous training on safety protocols, in addition to comprehensive documentation of incidents, procedures, and training, fosters a culture of safety and ensures compliance with regulatory standards.[101] In conclusion, a comprehensive approach to lab safety is indispensable for preserving both the accuracy of test results and the well-being of laboratory personnel in clinical settings.
Enhancing Healthcare Team Outcomes
Effective communication among interprofessional healthcare team members is crucial when laboratory results indicate a potential non-pancreatic cause for amylase level abnormalities. Moreover, it is equally important for the healthcare team to understand how various conditions can affect amylase levels.[102] Lipase is generally favored over amylase because of its greater specificity. Lipase levels usually stay elevated for up to 2 weeks, whereas amylase concentrations tend to return to normal within 5 days. Therefore, in cases where there is a gap between symptom onset and the patient seeking medical attention, amylase is less clinically valuable compared to lipase.[18]
The 2013 American College of Gastroenterology guidelines highlight that simultaneously ordering both lipase and amylase is neither cost-effective nor therapeutically advantageous. Furthermore, the healthcare providers emphasize that ordering amylase alone is an unreliable approach and does not enhance diagnostic efficiency compared to lipase.[12] Hence, when lipase testing is available, including amylase testing not only increases the cost for the patient but also provides minimal value in aiding the diagnosis of pancreatitis.[103]
References
Pieper-Bigelow C, Strocchi A, Levitt MD. Where does serum amylase come from and where does it go? Gastroenterology clinics of North America. 1990 Dec:19(4):793-810 [PubMed PMID: 1702756]
Zakowski JJ, Bruns DE. Biochemistry of human alpha amylase isoenzymes. Critical reviews in clinical laboratory sciences. 1985:21(4):283-322 [PubMed PMID: 2578342]
Azzopardi E, Lloyd C, Teixeira SR, Conlan RS, Whitaker IS. Clinical applications of amylase: Novel perspectives. Surgery. 2016 Jul:160(1):26-37. doi: 10.1016/j.surg.2016.01.005. Epub 2016 Apr 23 [PubMed PMID: 27117578]
Level 3 (low-level) evidenceReynolds TM. Amylase. British journal of hospital medicine (London, England : 2005). 2009 Jan:70(1):M8-9 [PubMed PMID: 19357566]
Chase CW, Barker DE, Russell WL, Burns RP. Serum amylase and lipase in the evaluation of acute abdominal pain. The American surgeon. 1996 Dec:62(12):1028-33 [PubMed PMID: 8955242]
Level 2 (mid-level) evidenceArgiris A, Mathur-Wagh U, Wilets I, Mildvan D. Abnormalities of serum amylase and lipase in HIV-positive patients. The American journal of gastroenterology. 1999 May:94(5):1248-52 [PubMed PMID: 10235202]
Pezzilli R, Andreone P, Morselli-Labate AM, Sama C, Billi P, Cursaro C, Barakat B, Gramenzi A, Fiocchi M, Miglio F, Bernardi M. Serum pancreatic enzyme concentrations in chronic viral liver diseases. Digestive diseases and sciences. 1999 Feb:44(2):350-5 [PubMed PMID: 10063922]
Rizvi AA. Serum amylase and lipase in diabetic ketoacidosis. Diabetes care. 2003 Nov:26(11):3193-4 [PubMed PMID: 14578269]
Level 3 (low-level) evidenceMuniraj T, Dang S, Pitchumoni CS. PANCREATITIS OR NOT?--Elevated lipase and amylase in ICU patients. Journal of critical care. 2015 Dec:30(6):1370-5. doi: 10.1016/j.jcrc.2015.08.020. Epub 2015 Sep 1 [PubMed PMID: 26411523]
Lenler-Petersen P, Grove A, Brock A, Jelnes R. alpha-Amylase in resectable lung cancer. The European respiratory journal. 1994 May:7(5):941-5 [PubMed PMID: 8050552]
Goldberg DM, Spooner RJ. Amylase, isoamylase and macroamylase. Digestion. 1975:13(1-2):56-75 [PubMed PMID: 1104398]
Level 3 (low-level) evidenceBarbieri JS, Riggio JM, Jaffe R. Amylase testing for abdominal pain and suspected acute pancreatitis. Journal of hospital medicine. 2016 May:11(5):366-8. doi: 10.1002/jhm.2544. Epub [PubMed PMID: 27160507]
Motoo Y. [Amylase]. Nihon rinsho. Japanese journal of clinical medicine. 2004 Nov:62 Suppl 11():387-9 [PubMed PMID: 15628424]
Peyrot des Gachons C, Breslin PA. Salivary Amylase: Digestion and Metabolic Syndrome. Current diabetes reports. 2016 Oct:16(10):102. doi: 10.1007/s11892-016-0794-7. Epub [PubMed PMID: 27640169]
Otsuki M. [Usefulness of amylase isoenzyme determination for the diagnosis of pancreatic diseases]. Nihon rinsho. Japanese journal of clinical medicine. 1995 May:53(5):1184-91 [PubMed PMID: 7541479]
Berk JE, Fridhandler L. Clinical application of amylase isoenzyme analysis. The American journal of gastroenterology. 1975 Jun:63(6):457-63 [PubMed PMID: 1146802]
Brault D, Bonnefoy A, Houry S, Dreux B, Bunodière M, Huguier M. [Acute pancreatitis and biochemical markers. Isoamylase]. Pathologie-biologie. 1985 Mar:33(3):195-9 [PubMed PMID: 2409510]
Rompianesi G, Hann A, Komolafe O, Pereira SP, Davidson BR, Gurusamy KS. Serum amylase and lipase and urinary trypsinogen and amylase for diagnosis of acute pancreatitis. The Cochrane database of systematic reviews. 2017 Apr 21:4(4):CD012010. doi: 10.1002/14651858.CD012010.pub2. Epub 2017 Apr 21 [PubMed PMID: 28431198]
Level 1 (high-level) evidenceIsmail OZ, Bhayana V. Lipase or amylase for the diagnosis of acute pancreatitis? Clinical biochemistry. 2017 Dec:50(18):1275-1280. doi: 10.1016/j.clinbiochem.2017.07.003. Epub 2017 Jul 16 [PubMed PMID: 28720341]
Giavarina D, Lippi G. Blood venous sample collection: Recommendations overview and a checklist to improve quality. Clinical biochemistry. 2017 Jul:50(10-11):568-573. doi: 10.1016/j.clinbiochem.2017.02.021. Epub 2017 Feb 27 [PubMed PMID: 28242283]
Level 2 (mid-level) evidenceLippi G, von Meyer A, Cadamuro J, Simundic AM. Blood sample quality. Diagnosis (Berlin, Germany). 2019 Mar 26:6(1):25-31. doi: 10.1515/dx-2018-0018. Epub [PubMed PMID: 29794250]
Level 2 (mid-level) evidenceKing LG, Seelig CB, Ranney JE. The lipase to amylase ratio in acute pancreatitis. The American journal of gastroenterology. 1995 Jan:90(1):67-9 [PubMed PMID: 7528469]
Level 2 (mid-level) evidenceLankisch PG, Petersen M. Lipase/amylase ratio: not helpful in the early etiological differentiation of acute pancreatitis. Zeitschrift fur Gastroenterologie. 1994 Jan:32(1):8-11 [PubMed PMID: 7511857]
Oshina I, Spigulis J. Beer-Lambert law for optical tissue diagnostics: current state of the art and the main limitations. Journal of biomedical optics. 2021 Oct:26(10):. doi: 10.1117/1.JBO.26.10.100901. Epub [PubMed PMID: 34713647]
Mäntele W, Deniz E. UV-VIS absorption spectroscopy: Lambert-Beer reloaded. Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy. 2017 Feb 15:173():965-968. doi: 10.1016/j.saa.2016.09.037. Epub 2016 Sep 21 [PubMed PMID: 27727137]
Gromashevskaia LL, Bogatyr' TV. [Serum amylase isoenzymes: their sources and clinical value of their determination (review of the literature)]. Laboratornoe delo. 1986:(8):451-7 [PubMed PMID: 2429044]
Takagi Y, Ishii T. [Methods of serum enzyme determination and its clinical significance: amylase inhibitors--with special reference to their application in the quantitative analysis of amylase isoenzymes in the human body fluids]. Rinsho byori. The Japanese journal of clinical pathology. 1983 Jun:Suppl 55():61-8 [PubMed PMID: 6197542]
Hamdan II, Afifi F, Taha MO. In vitro alpha amylase inhibitory effect of some clinically-used drugs. Die Pharmazie. 2004 Oct:59(10):799-801 [PubMed PMID: 15544061]
Klonoff DC. Macroamylasemia and other immunoglobulin-complexed enzyme disorders. The Western journal of medicine. 1980 Nov:133(5):392-407 [PubMed PMID: 6162278]
Wiederkehr JC, Wiederkehr BA, Wiederkehr HA, Carvalho CA. Nonspecific hyperamylasemia: a case report. JOP : Journal of the pancreas. 2013 Jan 10:14(1):74-6. doi: 10.6092/1590-8577/1216. Epub 2013 Jan 10 [PubMed PMID: 23306339]
Level 3 (low-level) evidenceCutolo M, Sulli A, Barone A, Picciotto A, Mangraviti S, Seriolo B, Accardo S. Macroamylasemia: a possible cause of unexplained hyperamylasemia in rheumatoid arthritis. British journal of rheumatology. 1995 Mar:34(3):290-2 [PubMed PMID: 7537158]
Level 3 (low-level) evidenceIshizuka T, Yasuda K, Kajita K, Sakata S, Kimura M, Ito Y, Miura K. Macroamylasemia associated with thyroid cancer, elevated serum thyroxine-binding globulin (TBG), chronic pancreatitis and gastrointestinal polyposis. Gastroenterologia Japonica. 1986 Aug:21(4):385-90 [PubMed PMID: 2429888]
Level 3 (low-level) evidenceLam R, Muniraj T. Hyperamylasemia. StatPearls. 2023 Jan:(): [PubMed PMID: 32644699]
Peng YF, Goyal H, Lin H, Liu DC, Li L. Serum amylase activity altered by the ABO blood group system in Chinese subjects. Journal of clinical laboratory analysis. 2019 Jun:33(5):e22883. doi: 10.1002/jcla.22883. Epub 2019 Apr 2 [PubMed PMID: 30938472]
Santos SVMD, Silva LAD, Terra FS, Souza AV, Espindola FS, Marziale MHP, Teixeira RR, Robazzi MLDCC. Association of salivary alpha-amylase with anxiety and stress in nursing professionals. Revista latino-americana de enfermagem. 2021:29():e3468. doi: 10.1590/1518-8345.4859.3468. Epub 2021 Aug 30 [PubMed PMID: 34468625]
Melnick S, Nazir S, Gish D, Aryal MR. Hypertriglyceridemic pancreatitis associated with confounding laboratory abnormalities. Journal of community hospital internal medicine perspectives. 2016:6(3):31808. doi: 10.3402/jchimp.v6.31808. Epub 2016 Jul 6 [PubMed PMID: 27406459]
Level 3 (low-level) evidenceGräsbeck R. Reference values, why and how. Scandinavian journal of clinical and laboratory investigation. Supplementum. 1990:201():45-53 [PubMed PMID: 2244183]
Liu W, Bretz F, Cortina-Borja M. Reference range: Which statistical intervals to use? Statistical methods in medical research. 2021 Feb:30(2):523-534. doi: 10.1177/0962280220961793. Epub 2020 Oct 14 [PubMed PMID: 33054684]
Lim E, Miyamura J, Chen JJ. Racial/Ethnic-Specific Reference Intervals for Common Laboratory Tests: A Comparison among Asians, Blacks, Hispanics, and White. Hawai'i journal of medicine & public health : a journal of Asia Pacific Medicine & Public Health. 2015 Sep:74(9):302-10 [PubMed PMID: 26468426]
Gillard BK, Simbala JA, Goodglick L. Reference intervals for amylase isoenzymes in serum and plasma of infants and children. Clinical chemistry. 1983 Jun:29(6):1119-23 [PubMed PMID: 6189641]
Morgenstern T, Niessen KH, Teufel M. [Value of isoamylases in the diagnosis of exocrine pancreatic insufficiency in childhood]. Monatsschrift Kinderheilkunde : Organ der Deutschen Gesellschaft fur Kinderheilkunde. 1984 Sep:132(9):661-5 [PubMed PMID: 6208482]
Furey C, Buxbaum J, Chambliss AB. A review of biomarker utilization in the diagnosis and management of acute pancreatitis reveals amylase ordering is favored in patients requiring laparoscopic cholecystectomy. Clinical biochemistry. 2020 Mar:77():54-56. doi: 10.1016/j.clinbiochem.2019.12.014. Epub 2019 Dec 31 [PubMed PMID: 31899279]
Nakajima K. Low serum amylase and obesity, diabetes and metabolic syndrome: A novel interpretation. World journal of diabetes. 2016 Mar 25:7(6):112-21. doi: 10.4239/wjd.v7.i6.112. Epub [PubMed PMID: 27022442]
Nakajima K, Nemoto T, Muneyuki T, Kakei M, Fuchigami H, Munakata H. Low serum amylase in association with metabolic syndrome and diabetes: A community-based study. Cardiovascular diabetology. 2011 Apr 17:10():34. doi: 10.1186/1475-2840-10-34. Epub 2011 Apr 17 [PubMed PMID: 21496338]
Level 2 (mid-level) evidenceBanks PA, Sidi S, Gelman ML, Lee KH, Warshaw AL. Amylase-creatinine clearance ratios and serum amylase isoenzymes in moderate renal insufficiency. Journal of clinical gastroenterology. 1979 Dec:1(4):331-5 [PubMed PMID: 95609]
Level 1 (high-level) evidenceTerui K, Hishiki T, Saito T, Mitsunaga T, Nakata M, Yoshida H. Urinary amylase/urinary creatinine ratio (uAm/uCr)--a less-invasive parameter for management of hyperamylasemia. BMC pediatrics. 2013 Dec 13:13():205. doi: 10.1186/1471-2431-13-205. Epub 2013 Dec 13 [PubMed PMID: 24330759]
Level 2 (mid-level) evidenceHansen SEJ, Langsted A, Varbo A, Madsen CM, Tybjærg-Hansen A, Nordestgaard BG. Low and high pancreatic amylase is associated with pancreatic cancer and chronic pancreatitis. European journal of epidemiology. 2021 Sep:36(9):975-984. doi: 10.1007/s10654-021-00801-0. Epub 2021 Sep 5 [PubMed PMID: 34482515]
Boybeyi O, Ergür AT, Dursun ZE, Gülerman F. Amylase/creatinine clearance ratio in diabetic ketoacidosis: a case report. Journal of pediatric endocrinology & metabolism : JPEM. 2014 Nov:27(11-12):1243-5. doi: 10.1515/jpem-2013-0466. Epub [PubMed PMID: 25153214]
Level 3 (low-level) evidenceTreacy J, Williams A, Bais R, Willson K, Worthley C, Reece J, Bessell J, Thomas D. Evaluation of amylase and lipase in the diagnosis of acute pancreatitis. ANZ journal of surgery. 2001 Oct:71(10):577-82 [PubMed PMID: 11552931]
Smith RC, Southwell-Keely J, Chesher D. Should serum pancreatic lipase replace serum amylase as a biomarker of acute pancreatitis? ANZ journal of surgery. 2005 Jun:75(6):399-404 [PubMed PMID: 15943725]
Yang RW, Shao ZX, Chen YY, Yin Z, Wang WJ. Lipase and pancreatic amylase activities in diagnosis of acute pancreatitis in patients with hyperamylasemia. Hepatobiliary & pancreatic diseases international : HBPD INT. 2005 Nov:4(4):600-3 [PubMed PMID: 16286272]
Ashraf H, Colombo JP, Marcucci V, Rhoton J, Olowoyo O. A Clinical Overview of Acute and Chronic Pancreatitis: The Medical and Surgical Management. Cureus. 2021 Nov:13(11):e19764. doi: 10.7759/cureus.19764. Epub 2021 Nov 20 [PubMed PMID: 34938639]
Level 3 (low-level) evidencePham A, Forsmark C. Chronic pancreatitis: review and update of etiology, risk factors, and management. F1000Research. 2018:7():. pii: F1000 Faculty Rev-607. doi: 10.12688/f1000research.12852.1. Epub 2018 May 17 [PubMed PMID: 29946424]
Hiele M, Ghoos Y, Rutgeerts P, Vantrappen G. Effects of acarbose on starch hydrolysis. Study in healthy subjects, ileostomy patients, and in vitro. Digestive diseases and sciences. 1992 Jul:37(7):1057-64 [PubMed PMID: 1618053]
Garrison R. Amylase. Emergency medicine clinics of North America. 1986 May:4(2):315-27 [PubMed PMID: 2422011]
Hiatt JR, Calabria RP, Passaro E Jr, Wilson SE. The amylase profile: a discriminant in biliary and pancreatic disease. American journal of surgery. 1987 Nov:154(5):490-2 [PubMed PMID: 2445215]
Jeong IH, Jung YS, Kim H, Kim BW, Kim JW, Hong J, Wang HJ, Kim MW, Yoo BM, Kim JH, Han JH, Kim WH. Amylase level in extrahepatic bile duct in adult patients with choledochal cyst plus anomalous pancreatico-biliary ductal union. World journal of gastroenterology. 2005 Apr 7:11(13):1965-70 [PubMed PMID: 15800987]
Level 2 (mid-level) evidenceCollen MJ, Ansher AF, Chapman AB, Mackow RC, Lewis JH. Serum amylase in patients with renal insufficiency and renal failure. The American journal of gastroenterology. 1990 Oct:85(10):1377-80 [PubMed PMID: 1699413]
Mizuno S, Hanamura I, Ota A, Karnan S, Narita T, Ri M, Mizutani M, Goto M, Gotou M, Tsunekawa N, Shikami M, Iida S, Hosokawa Y, Miwa H, Ueda R, Nitta M, Takami A. Overexpression of salivary-type amylase reduces the sensitivity to bortezomib in multiple myeloma cells. International journal of hematology. 2015 Nov:102(5):569-78. doi: 10.1007/s12185-015-1859-0. Epub 2015 Sep 4 [PubMed PMID: 26341959]
Shigemura M, Moriyama T, Shibuya H, Obara M, Endo T, Hashino S, Yokouchi H, Asaka M, Shimizu C, Chiba H, Nishimura M. Multiple myeloma associated with sialyl salivary-type amylase. Clinica chimica acta; international journal of clinical chemistry. 2007 Feb:376(1-2):121-5 [PubMed PMID: 16979610]
Ross CM, Devgun MS, Gunn IR. Hyperamylasaemia and multiple myeloma. Annals of clinical biochemistry. 2002 Nov:39(Pt 6):616-20 [PubMed PMID: 12564849]
Level 3 (low-level) evidenceMitura K, Romanczuk M. Ruptured ectopic pregnancy mimicking acute pancreatitis. Ginekologia polska. 2009 May:80(5):383-5 [PubMed PMID: 19548460]
Level 3 (low-level) evidenceHo ET, Gardner DS. Paraganglioma with acute hyperamylasaemia masquerading as acute pancreatitis. Singapore medical journal. 2011 Dec:52(12):e251-4 [PubMed PMID: 22159946]
Level 3 (low-level) evidenceWan S, Arifi AA, Chan CS, Ng CS, Wan IY, Lee TW, Yim AP. Is hyperamylasemia after cardiac surgery due to cardiopulmonary bypass? Asian cardiovascular & thoracic annals. 2002 Jun:10(2):115-8 [PubMed PMID: 12079932]
Gullo L. Benign pancreatic hyperenzymemia. Digestive and liver disease : official journal of the Italian Society of Gastroenterology and the Italian Association for the Study of the Liver. 2007 Jul:39(7):698-702 [PubMed PMID: 17531557]
Birtolo C, Migliori M, Drewes AM, Tomassetti P, Imbrogno A, Fusaroli P, Casadei R, Ricci C, Stanghellini V, De Giorgio R. Benign Pancreatic Hyperenzymemia: Lights on a Clinical Challenge. Pancreas. 2017 Jan:46(1):5-7 [PubMed PMID: 27977626]
Pezzilli R, Barassi A, Morselli-Labate AM, Fantini L, Tomassetti P, Campana D, Casadei R, Finazzi S, d'Eril GM, Corinaldesi R. Fecal calprotectin and elastase 1 determinations in patients with pancreatic diseases: a possible link between pancreatic insufficiency and intestinal inflammation. Journal of gastroenterology. 2007 Sep:42(9):754-60 [PubMed PMID: 17876545]
Bloch RS, Weaver DW, Bouwman DL, Berger G. Alcohol-induced salivary hyperamylasemia. The Journal of surgical research. 1984 Apr:36(4):389-94 [PubMed PMID: 6200693]
Scheutzel P, Gerlach U. [Alpha-amylase isoenzymes in serum and saliva of patients with anorexia and bulimia nervosa]. Zeitschrift fur Gastroenterologie. 1991 Jul:29(7):339-45 [PubMed PMID: 1950041]
Monteleone P, Scognamiglio P, Monteleone AM, Mastromo D, Steardo L Jr, Serino I, Maj M. Abnormal diurnal patterns of salivary α-amylase and cortisol secretion in acute patients with anorexia nervosa. The world journal of biological psychiatry : the official journal of the World Federation of Societies of Biological Psychiatry. 2011 Sep:12(6):455-61. doi: 10.3109/15622975.2011.590226. Epub 2011 Jul 11 [PubMed PMID: 21745126]
Yamamoto H, Kuroda R. [Amylase producing tumor]. Ryoikibetsu shokogun shirizu. 1994:(4):17-9 [PubMed PMID: 7516440]
Vuković A, Kuna K, Lončar Brzak B, Vučičević Boras V, Šeparović R, Šekerija M, Šumilin L, Vidranski V. THE ROLE OF SALIVARY AND SERUM CA125 AND ROUTINE BLOOD TESTS IN PATIENTS WITH OVARIAN MALIGNANCIES. Acta clinica Croatica. 2021 Mar:60(1):55-62. doi: 10.20471/acc.2021.60.01.08. Epub [PubMed PMID: 34588722]
Otsuki M, Yuu H, Maeda M, Saeki S, Yamasaki T. Amylase in the lung. Cancer. 1977 Apr:39(4):1656-63 [PubMed PMID: 856449]
Zhang J, Zhang L, Pan S, Gu B, Zhen Y, Yan J, Zhou Y. Amylase: sensitive tumor marker for amylase-producing lung adenocarcinoma. Journal of thoracic disease. 2013 Aug:5(4):E167-9. doi: 10.3978/j.issn.2072-1439.2013.08.37. Epub [PubMed PMID: 23991331]
Level 3 (low-level) evidenceGuo S, Lv H, Yan L, Rong F. Hyperamylasemia may indicate the presence of ovarian carcinoma: A case report. Medicine. 2018 Dec:97(49):e13520. doi: 10.1097/MD.0000000000013520. Epub [PubMed PMID: 30544453]
Level 3 (low-level) evidenceObiekwe BC, Chard T. What do placental function tests predict? Observations on placental lactogen levels in growth retardation and fetal distress. European journal of obstetrics, gynecology, and reproductive biology. 1982 Nov:14(2):69-73 [PubMed PMID: 7173482]
Chandra D, Bsavaraju M, Mr R, Av A, R S. Serum Amylase and Lipase Estimation in Diabetic Ketoacidosis. The Journal of the Association of Physicians of India. 2022 Apr:70(4):11-12 [PubMed PMID: 35443366]
Serene TEL, G SV, Padmakumar JS, Terence HCW, Keem LJ, Bei W, Winston WWL. Predictive value of post-operative drain amylase levels for post-operative pancreatic fistula. Annals of hepato-biliary-pancreatic surgery. 2018 Nov:22(4):397-404. doi: 10.14701/ahbps.2018.22.4.397. Epub 2018 Nov 27 [PubMed PMID: 30588532]
Kasapoğlu F, Ozmen OA, Coşkun H, Erişen L, Onart S. Evaluation of amylase levels in the neck drainage and serum for early diagnosis of the pharyngocutaneous fistula. Kulak burun bogaz ihtisas dergisi : KBB = Journal of ear, nose, and throat. 2009 Mar-Apr:19(2):67-70 [PubMed PMID: 19796002]
Medeiros MM, Fernandes GH, Pinto NS, Silveira VA. Clinical and subclinical pancreatitis in a cohort of patients diagnosed with systemic lupus erythematosus. Clinical and experimental rheumatology. 2011 Sep-Oct:29(5):776-82 [PubMed PMID: 21962107]
Kopáčová M, Bureš J, Rejchrt S, Vávrová J, Bártová J, Soukup T, Tomš J, Tachecí I. Risk Factors of Acute Pancreatitis in Oral Double Balloon Enteroscopy. Acta medica (Hradec Kralove). 2016:59(3):84-90. doi: 10.14712/18059694.2016.95. Epub 2016 Sep 1 [PubMed PMID: 27638962]
Herman R, Guire KE, Burd RS, Mooney DP, Ehlrich PF. Utility of amylase and lipase as predictors of grade of injury or outcomes in pediatric patients with pancreatic trauma. Journal of pediatric surgery. 2011 May:46(5):923-6. doi: 10.1016/j.jpedsurg.2011.02.033. Epub [PubMed PMID: 21616253]
Bayot ML, Lopes JE, Naidoo P. Clinical Laboratory. StatPearls. 2023 Jan:(): [PubMed PMID: 30570979]
Wadhwa V, Rai S, Thukral T, Chopra M. Laboratory quality management system: road to accreditation and beyond. Indian journal of medical microbiology. 2012 Apr-Jun:30(2):131-40. doi: 10.4103/0255-0857.96647. Epub [PubMed PMID: 22664426]
Level 2 (mid-level) evidenceKinns H, Pitkin S, Housley D, Freedman DB. Internal quality control: best practice. Journal of clinical pathology. 2013 Dec:66(12):1027-32. doi: 10.1136/jclinpath-2013-201661. Epub 2013 Sep 26 [PubMed PMID: 24072731]
Level 2 (mid-level) evidenceWestgard JO. Internal quality control: planning and implementation strategies. Annals of clinical biochemistry. 2003 Nov:40(Pt 6):593-611 [PubMed PMID: 14629798]
Level 2 (mid-level) evidenceSkitek M, Martinello F, Jerin A. How to Really Understand and Improve the System of Internal Quality Control and External Quality Assessment in the Accreditation Process of the Medical Laboratory? EJIFCC. 2022 Apr:33(1):23-27 [PubMed PMID: 35645692]
Level 2 (mid-level) evidenceMishra B, Das BKL, Khan SA, Gelal B, Niraula A, Chaudhari RK, Lamsal M. Knowledge of Internal Quality Control for Laboratory Tests among Laboratory Personnel Working in Department of Biochemistry in a Tertiary Care Center: A Descriptive Cross-sectional Study. JNMA; journal of the Nepal Medical Association. 2023 Feb 1:61(258):167-170. doi: 10.31729/jnma.8040. Epub 2023 Feb 1 [PubMed PMID: 37203967]
Level 2 (mid-level) evidenceNichols JH. Verification of method performance for clinical laboratories. Advances in clinical chemistry. 2009:47():121-37 [PubMed PMID: 19634779]
Level 3 (low-level) evidenceKearney E. Internal quality control. Methods in molecular biology (Clifton, N.J.). 2013:1065():277-89. doi: 10.1007/978-1-62703-616-0_18. Epub [PubMed PMID: 23996371]
Level 2 (mid-level) evidenceBayat H. Selecting multi-rule quality control procedures based on patient risk. Clinical chemistry and laboratory medicine. 2017 Oct 26:55(11):1702-1708. doi: 10.1515/cclm-2016-1077. Epub [PubMed PMID: 28236626]
Level 2 (mid-level) evidenceMiller WG, Jones GR, Horowitz GL, Weykamp C. Proficiency testing/external quality assessment: current challenges and future directions. Clinical chemistry. 2011 Dec:57(12):1670-80. doi: 10.1373/clinchem.2011.168641. Epub 2011 Sep 30 [PubMed PMID: 21965556]
Level 2 (mid-level) evidenceShahangian S. Proficiency testing in laboratory medicine: uses and limitations. Archives of pathology & laboratory medicine. 1998 Jan:122(1):15-30 [PubMed PMID: 9448012]
Laubender RP, Geistanger A. Selection of within-run quality control rules for laboratory biomarkers. Statistics in medicine. 2021 Jul 20:40(16):3645-3666. doi: 10.1002/sim.8987. Epub 2021 Apr 19 [PubMed PMID: 33876446]
Level 2 (mid-level) evidenceKristensen GB, Meijer P. Interpretation of EQA results and EQA-based trouble shooting. Biochemia medica. 2017 Feb 15:27(1):49-62. doi: 10.11613/BM.2017.007. Epub [PubMed PMID: 28392726]
Earley MC, Astles JR, Breckenridge K. Practices and Perceived Value of Proficiency Testing in Clinical Laboratories. The journal of applied laboratory medicine. 2017 Jan:1(4):415-420. doi: 10.1373/jalm.2016.021469. Epub 2019 Oct 15 [PubMed PMID: 31903445]
Wagar EA, Yuan S. The laboratory and patient safety. Clinics in laboratory medicine. 2007 Dec:27(4):909-30, viii-ix [PubMed PMID: 17950905]
Ejilemele AA, Ojule AC. Health and safety in clinical laboratories in developing countries: safety considerations. Nigerian journal of medicine : journal of the National Association of Resident Doctors of Nigeria. 2004 Apr-Jun:13(2):182-8 [PubMed PMID: 15293842]
Cornish NE, Anderson NL, Arambula DG, Arduino MJ, Bryan A, Burton NC, Chen B, Dickson BA, Giri JG, Griffith NK, Pentella MA, Salerno RM, Sandhu P, Snyder JW, Tormey CA, Wagar EA, Weirich EG, Campbell S. Clinical Laboratory Biosafety Gaps: Lessons Learned from Past Outbreaks Reveal a Path to a Safer Future. Clinical microbiology reviews. 2021 Jun 16:34(3):e0012618. doi: 10.1128/CMR.00126-18. Epub 2021 Jun 9 [PubMed PMID: 34105993]
Adyanthaya S, Jose M. Quality and safety aspects in histopathology laboratory. Journal of oral and maxillofacial pathology : JOMFP. 2013 Sep:17(3):402-7. doi: 10.4103/0973-029X.125207. Epub [PubMed PMID: 24574660]
Level 2 (mid-level) evidenceIonescu G, Neguţ M, Combiescu AA. [Biosafety and biosecurity in the medical laboratory. Update and trends]. Bacteriologia, virusologia, parazitologia, epidemiologia (Bucharest, Romania : 1990). 2007 Jul-Dec:52(3-4):91-9 [PubMed PMID: 19326721]
Logie JJ, Cox M, Sharkey J, Williams A. A multidisciplinary approach to an unusual cause of hyperamylasaemia. BMJ case reports. 2015 Jul 6:2015():. doi: 10.1136/bcr-2015-209780. Epub 2015 Jul 6 [PubMed PMID: 26150631]
Level 3 (low-level) evidenceBeauregard JM, Lyon JA, Slovis C. Using the literature to evaluate diagnostic tests: amylase or lipase for diagnosing acute pancreatitis? Journal of the Medical Library Association : JMLA. 2007 Apr:95(2):121-6 [PubMed PMID: 17443244]
Level 3 (low-level) evidence