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HelpTest Code 199PC Carbohydrate Antigen 19-9 (CA 19-9), Pancreatic Cyst Fluid
Reporting Name
CA19-9, Pancreatic CystUseful For
As an adjunct in the assessment of pancreatic cysts, when used in conjunction with carcinoembryonic antigen, amylase, imaging studies and cytology
Method Name
Immunoenzymatic Assay
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
Pancreatic Cyst FluidOrdering Guidance
This test should not be ordered for pancreatic fluid of noncystic origin (eg, pancreatic duct fluid, peripancreatic fluid) since reference values have not been established for those specimen types. For ordering assistance call 800-533-1710.
Specimen Required
Patient Preparation: For 12 hours before this procedure do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.
Container/Tube: Plain, plastic, screw-top tube
Specimen Volume: 1 mL
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Pancreatic Cyst Fluid | Frozen (preferred) | 90 days | |
| Refrigerated | 7 days | ||
| Ambient | 72 hours |
Reject Due To
| Gross hemolysis | Reject |
| Gross icterus | OK |
Reference Values
An interpretive report will be provided.
Day(s) Performed
Monday through Friday
CPT Code Information
86301
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| 199PC | CA19-9, Pancreatic Cyst | 97750-4 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 199P | CA19-9, Pancreatic Cyst | 97750-4 |
| SITE6 | Site | 39111-0 |
Clinical Information
Carbohydrate antigen 19-9 (CA 19-9) is a modified Lewis(a) blood group antigen that has been used as a tumor marker. Serum CA 19-9 concentrations may be elevated in patients with gastrointestinal malignancies, such as cholangiocarcinoma, colon cancer, or pancreatic cancer. While serum CA 19-9 is neither sensitive nor specific for pancreatic cancer, concentrations of CA 19-9 in pancreatic cyst fluid may help determine whether a pancreatic cyst is benign.
Cystic lesions of the pancreas are of various types:
Benign cysts:
-Inflammatory cysts (pseudocysts)
-Serous cysts (serous cystadenoma)
Mucinous cysts:
-Premalignant (mucinous cystadenoma)
-Malignant (cystadenocarcinoma, intrapapillary mucinous neoplasia)
Pancreatic cyst fluid CA 19-9 results should be used in conjunction with imaging studies, cytology, and other cyst-fluid tumor markers, such as carcinoembryonic antigen and amylase.
Interpretation
Cyst fluid carbohydrate antigen 19-9 (CA19-9) concentrations less than 37 U/mL indicate a low risk for a mucinous cyst and are more consistent with serous cystadenoma or pseudocyst. The sensitivity and specificity are approximately 19% and 98%, respectively, at this concentration.
Correlation of these test results with cytology and imaging is recommended.
Cautions
Carbohydrate antigen 19-9 (CA 19-9) and other tumor markers are not specific for malignancy, and CA 19-9 testing has limited utility when used as the sole tumor marker test. Other tests (eg, carcinoembryonic antigen, amylase, cytology) should be performed in conjunction with CA 19-9 for assessing pancreatic cyst aspirates.
A low or negative result (<5 U/mL) may be uninformative or misleading since some individuals (Lewis nonsecretors) do not produce the CA 19-9 antigen. In such cases, a serum CA 19-9 measurement is necessary to verify that the patient is (or is not) a CA 19-9 secretor.
In rare cases, some individuals can develop antibodies to mouse or other animal antibodies (often referred to as human anti-mouse antibodies [HAMA] or heterophile antibodies), which may cause interference in some immunoassays. Caution should be used in interpretation of results, and the laboratory should be alerted if the result does not correlate with the clinical presentation.
Method Description
The Access GI Monitor assay is a 2-site immunoenzymatic sandwich assay. A sample is added to a reaction vessel along with paramagnetic particles coated with polyclonal goat antibiotin antibody, mouse monoclonal biotin conjugate, and buffered protein solution. After incubation in a reaction vessel, separation in a magnetic field, and washing to remove materials not bound to the solid phase, a monoclonal-alkaline phosphatase conjugate is added. After incubation in a reaction vessel, materials bound to the solid phase are held in a magnetic field, while unbound materials are washed away. The chemiluminescent substrate Lumi-Phos 530 is added to the vessel and light generated by the reaction is measured with a luminometer. The light production is directly proportional to the concentration of CA 19-9 antigen in the sample. The amount of analyte in the sample is determined from a stored, multipoint calibration curve.(Package insert: Access GI Monitor. Beckman Coulter, Inc.; 04/2019)