CA 19-9 (Carbohydrate Antigen 19-9); Cancer Antigen 19-9 (CA 19-9); GI Cancer Antigen
Test ID
CA19
General Information
Useful for:
Potentially for diagnosis and monitoring of pancreatic cancer
Potentially differentiating patients with cholangiocarcinoma and primary sclerosing cholangitis (PSC) from those with PSC alone
Specimen Type
Serum
Specimen Requirements
Preferred: Serum Gel
Acceptable: Red Top
Specimen Collection / Processing Instructions
Patient Preparation: For 12 hours before specimen collection do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins
Serum gel tubes should be centrifuged within 2 hours of collection.
Red-top tubes should be centrifuged and aliquoted within 2 hours of collection
Minimum Sample Volume
0.5 mL
Stability
Refrigerated (preferred): 7 days
Frozen: 90 days
Ambient: 8 hours
Unacceptable Specimen Conditions
Gross hemolysis
Limitations
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 anti-animal antibodies present. These antibodies may interfere with the assay reagents to produce unreliable results
