Aiding in distinguishing between pseudocysts and other types of pancreatic cysts when used in conjunction with imaging studies, cytology, and other pancreatic cyst fluid tumor markers
Substrate Kinetic
Pancreatic Cyst Fluid
For other body fluid specimens (eg, peritoneal, pleural), order AMBF / Amylase, Body Fluid. Testing will be changed to AMBF if this test is ordered on any fluid other than pancreatic fluid.
Question ID | Description | Answers |
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SITE6 | Site |
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Container/Tube: Plain vial
Specimen Volume: 1 mL
Additional Information: A minimum of 0.5 mL is required for testing; specimens less than 0.5 mL may be rejected.
If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
-Oncology Test Request (T729)
0.5 mL
Gross hemolysis | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Pancreatic Cyst Fluid | Frozen (preferred) | 30 days | |
Ambient | 7 days | ||
Refrigerated | 7 days |
Aiding in distinguishing between pseudocysts and other types of pancreatic cysts when used in conjunction with imaging studies, cytology, and other pancreatic cyst fluid tumor markers
Amylases are a group of hydrolases that degrade complex carbohydrates into fragments. Amylase is produced by the exocrine pancreas and the salivary glands to aid in the digestion of starch. It is also produced by the small intestine mucosa, ovaries, placenta, liver, and fallopian tubes.
Measurement of amylase in pancreatic cyst fluid is often used in conjunction with tumor markers carcinoembryonic antigen, and CA19-9 as an aid in the differential diagnosis of pancreatic cysts lesions. Amylase seems to be particularly helpful in excluding pancreatic pseudocysts. A number of studies have demonstrated that amylase levels are typically very high, usually in the thousands in pseudocysts, therefore, low amylase values virtually exclude pseudocysts. Based on the evidence available, the American College of Gastroenterology practice guidelines for the Diagnosis and Management of Neoplastic Pancreatic Cysts suggest that an amylase cutoff value of 250 U/L is useful to exclude pseudocysts.
An interpretive report will be provided.
A pancreatic cyst fluid amylase concentration of less than 250 U/L indicates a low risk of a pseudocyst and is more consistent with cystic neoplasms such as mucinous cystic neoplasms (MCN), intraductal papillary mucinous neoplasm (IPMN), serous cystadenomas, cystic neuroendocrine tumor, and mucinous cystadenocarcinoma. High pancreatic cyst fluid amylase values are nonspecific and occur both in pseudocysts and some mucin-producing cystic neoplasms including MCN, IPMN, and mucinous cystadenocarcinoma.
In-house studies showed that using a cutoff value of less than 250 U/L to exclude a pseudocyst has 94% sensitivity and 42% specificity. Cysts with amylase levels of less than 250 U/L included 69% of adenocarcinomas, 31% of intraductal papillary mucinous neoplasia, 55% of mucinous cystadenomas, 64% serous cystadenomas, and 6% of pseudocysts.
This test result should not be the sole basis for diagnosis. Test results should always be correlated with imaging and cytology.
In-house studies to verify the cutoff value of 250 U/L showed that 94% (66/70) of pseudocysts had a value of greater than or equal to 250 U/L. Cysts with amylase levels of less than 250 U/L included 69% of adenocarcinomas, 31% of intraductal papillary mucinous neoplasia, 55% of mucinous cystadenomas, 64% serous cystadenomas, and 6% of pseudocysts. Therefore, using a cutoff of less than 250 U/L to exclude a pseudocyst has 94% sensitivity and 42% specificity.
1. Snozek CL, Mascarenhas RC, O'Kane DJ. Use of cyst fluid CEA, CA19-9, and amylase for evaluation of pancreatic lesions. Clin Biochem. 2009;42(15):1585-1588
2. van der Waaij LA, van Dullemen HM, Porte RJ. Cyst fluid analysis in the differential diagnosis of pancreatic cystic lesions: a pooled analysis. Gastrointest Endosc. 2005;62(3):383-389
3. Elta GH, Enestvedt BK, Sauer BG, Lennon AM. ACG clinical guideline: Diagnosis and management of pancreatic cysts. Am J Gasroenterol. 2018;113(4):464-479
4. Brugge WR. Diagnosis and management of cystic lesions of the pancreas. J Gastrointest Oncol. 2015;6(4):375-388. doi:10.3978/j.issn.2078-6891.2015.057
The Roche amylase method is an enzymatic colorimetric test using 4,6-ethylidene (G7)-p-nitrophenol (G1)-alpha, D-maltoheptaoside (ethylidene-G7PNP) as a substrate. Human salivary and pancreatic amylases (alpha-amylase) convert the substrate at approximately the same rate. The alpha-amylase cleaves the substrate into G2, G3, G4 p-nitrophenol (PNP) fragments. The G2, G3, and G4 PNP fragments are further hydrolyzed by an alpha-glucosidase to yield PNP and glucose. The rate of increase in absorbance at 415 nm (measuring the increase in PNP) is directly proportional to amylase activity.(Package insert: Roche AMYL2 reagent. Roche Diagnostic Corp; V10 12/2018)
Monday through Saturday
This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.
82150
Test Id | Test Order Name | Order LOINC Value |
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AMLPC | Amylase, Pancreatic Cyst | 48996-3 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
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SITE6 | Site | 39111-0 |
AMYPC | Amylase, Pancreatic Cyst | 48996-3 |