Sign in →

Catalog ID CA 19-9 CA 19-9

Important Note

Carbohydrate antigen 19-9 (CA 19-9) is neither specific nor sensitive enough to be used as a cancer screen.

Specimen Requirements

Serum

Collect 2.0 mL blood in Gold top tube.

Storage and Transport

Room Temperature: serum for 8 hours

Refrigerated: serum for 48 hours

Frozen: serum for 6 months at -20C

Causes for Rejection

Quantity insufficient, wrong tube, hemolyzed

Turn Around Time

Within 3 hours from laboratory receipt, M-F

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 below 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 Interval

Reference Interval: <2.0 - 37.0 U/mL

Interpretation

Serial monitoring of carbohydrate antigen 19-9 (CA 19-9) should begin prior to therapy to verify post-therapy decreases in CA 19-9 and to establish a baseline for evaluating possible recurrence. Single values of CA 19-9 are less informative.

Elevated values may be caused by a variety of malignant and nonmalignant conditions including cholangiocarcinoma, pancreatic cancer, and/or colon cancer.

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.

Methodology

Immunoassay

CPT Code

86301

Performing Laboratory

Core Laboratory, AD3301 706-721-2120