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HelpTest ID CA19 Carbohydrate Antigen 19-9 (CA 19-9), Serum
Useful For
Potentially useful adjunct for diagnosis and monitoring of pancreatic cancer
May be used for differentiating patients with cholangiocarcinoma and primary sclerosing cholangitis (PSC) from those with PSC alone
Method Name
Immunoenzymatic Assay
Reporting Name
Carbohydrate Ag 19-9, SSpecimen Type
SerumContainer/Tube:
Preferred: Serum gel
Acceptable: Red top
Specimen Volume: 0.6 mL
Collection Instructions:
1. Serum gel tubes should be centrifuged within 2 hours of collection.
2. Red-top tubes should be centrifuged and aliquoted within 2 hours of collection.
Additional Information: Twelve hours before this blood test, do not take multivitamins or dietary supplements containing biotin or vitamin B7 that are commonly found in hair, skin and nail supplements and multivitamins.
Forms: If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
Oncology Test Request Form (T729) (http://www.mayomedicallaboratories.com/it-mmfiles/oncology-request-form.pdf)
General Request Form (T239) (http://www.mayomedicallaboratories.com/it-mmfiles/general-request-form.pdf)
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Refrigerated (preferred) | 7 days |
| Frozen | 90 days |
Clinical Information
Carbohydrate antigen 19-9 (CA 19-9) is a modified Lewis(a) blood group antigen. CA 19-9 may be elevated in patients with gastrointestinal malignancies such as cholangiocarcinoma, pancreatic cancer, or colon cancer.
Benign conditions such as cirrhosis, cholestasis, and pancreatitis also result in elevated serum CA 19-9 concentrations but in these cases values usually are <1,000 U/mL.
Individuals that are Lewis negative (5%-7% of the population) do not express CA 19-9 due to the lack of the enzyme fucosyltransferase needed for CA 19-9 production. In these individuals, a low or undetectable serum CA 19-9 concentration is not informative regarding cancer recurrence.
Reference Values
<55 U/mL
Serum markers are not specific for malignancy, and values may vary by method.
Cautions
Twelve hours before this blood test, do not take multivitamins or dietary supplements containing biotin or vitamin B7 that are commonly found in hair, skin and nail supplements and multivitamins.
Carbohydrate antigen 19-9 (CA 19-9) is neither specific nor sensitive enough to be used as a cancer screen.
Some individuals do not express CA 19-9. Consequently low values in these individuals are not informative regarding cancer recurrence.
Do not interpret serum CA 19-9 levels as absolute evidence of the presence or the absence of malignant disease. Use serum CA 19-9 in conjunction with information from the clinical evaluation of the patient and other diagnostic procedures.
Some patients who have been exposed to animal antigens, either in the environment or as part of treatment or imaging procedures, may have circulating antianimal antibodies present. These antibodies may interfere with the assay reagents to produce unreliable results.
Day(s) Performed
Monday through Friday; 5 a.m.-12 a.m.
Saturday; 6 a.m.-6 p.m.
Report Available
Same day/1 dayPerforming Laboratory
Mayo Medical Laboratories in Rochester
Test Classification
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
86301