Amylase, Total, Serum
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Diagnosis and management of pancreatitis
Evaluation of pancreatic function
Colorimetric Rate Reaction
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Amylase, Total, S
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Preferred: Serum gel
Acceptable: Red top
Specimen Volume: 0.5 mL
Additional Information: Patient's age and sex are required.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Mild OK; Gross reject
Mild OK; Gross OK
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
|Serum||Frozen (preferred)||30 days|
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Amylases are a group of hydrolases that degrade complex carbohydrates into fragments. Amylase is produced primarily by the exocrine pancreas where the enzyme is synthesized by the acinar cells and then secreted into the intestinal tract by way of the pancreatic duct system. Amylases also are produced by the salivary glands, small intestine mucosa, ovaries, placenta, liver, and fallopian tubes. Pancreatic and salivary isoenzymes are found in serum.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
0-30 days: 0-6 U/L
31-182 days: 1-17 U/L
183-365 days: 6-44 U/L
1-3 years: 8-79 U/L
4-17 years: 21-110 U/L
> or =18 years: 26-102 U/L
In acute pancreatitis, a transient rise in serum amylase activity occurs within 2 to 12 hours of onset; levels return to normal by the third or fourth day. A 4- to 6-fold elevation of amylase activity above the reference limit is usual with the maximal levels obtained in 12 to 72 hours. However, a significant number of subjects show lesser elevations and sometimes none. The magnitude of the elevation of serum enzyme activity is not related to the severity of pancreatic involvement. Normalization is not necessarily a sign of resolution.
In acute pancreatitis associated with hyperlipidemia, serum amylase activity may be spuriously normal; the amylasemia may be unmasked either by serial dilution of the serum or ultracentrifugation.
A significant amount of serum amylase is excreted in the urine, and therefore, elevation of serum activity is reflected in the rise of urinary amylase activity. Urine amylase, as compared to serum amylase, appears to be more frequently elevated, reaches higher levels and persists for longer periods. However, the receiver operator curves (ROC) of various serum and urine amylase assays demonstrated that all urine assays had poorer diagnostic utility than all serum assays. In quiescent chronic pancreatitis, both serum and urine activities are usually subnormal.
Because it is produced by several organs, amylase is not a specific indicator of pancreatic function. Elevated levels also may be seen in a number of nonpancreatic disease processes including mumps, salivary duct obstruction, ectopic pregnancy, and intestinal obstruction/infarction.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Amylase results may be elevated in patients with macroamylase. Macroamylase refers to a high molecular weight form of amylase that is present in a patient's serum. Different causes of macroamylase have been suggested, the most common being amylase complexed with an immunoglobulin. The large size of the macroamylase complex prevents its excretion in the urine. As a result, the serum amylase is usually elevated. This elevated amylase is not diagnostic for pancreatitis. By utilizing serum lipase and urinary amylase, the presence or absence of macroamylase may be determined.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Soldin SJ: Pediatric Reference Ranges, AACC Press, Washington DC, Second edition. 1997
2. Tietz Textbook of Clinical Chemistry. Edited by CA Burtis, ER Ashwood. WB Saunders Company, Philadelphia, 1999
3. Swaroop VS, Chari ST, Clain JE: Acute pancreatitis, JAMA 2004;291:2865-2868
Method Description Describes how the test is performed and provides a method-specific reference
The liquid Roche amylase (AMYL) method is an enzymatic colorimetric test using 4,6-ethyliden (G7)-p-nitrophenol (G1)-a, D-maltoheptaoside (ethylidene-G7PNP) as a substrate. Human salivary and pancreatic amylase convert the substrate at approximately the same rate. The a-amylase cleaves the substrate into G2, G3, G4 PNP fragments. The G2 and G3 and G4 PNP fragments are further hydrolyzed by an a-glucosidase to yield p-nitrophenol and glucose. The rate of increase in absorbance at 415 nm (measuring the increase in p-nitrophenol) is proportional to amylase activity.(Package insert: Roche AMYL reagent, Indianapolis, IN, February 2000)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Sunday; Continuously
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Same day/1 day
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
|Result ID||Reporting Name||LOINC Code|
|AMS||Amylase, Total, S||1798-8|