CA 19-9 (synonym: carbohydrate antigen 19-9; gastrointestinal cancer antigen) is a so-called tumor marker. Tumor markers are endogenous substances that are produced by tumors and can be detected in the blood. They can provide an indication of a malignant (malignant) neoplasm and are used as a follow-up test in cancer aftercare.
The procedure
Material needed
- Blood serum
Preparation of the patient
- Not necessary
Disruptive factors
- None known
Normal value
| Normal value | <37 U/ml |
Indications
- Initial markers at:
- Pancreatic cancer (cancer of the pancreas) [mainly for follow-up of pancreatic cancer].
- Hepatobiliary carcinoma
- Liver metastases
- Secondary markers in:
- Gastric carcinoma (in association with CEA).
- Colon carcinoma (in association with CEA).
- Ovarian carcinoma (ovarian cancer)
Interpretation
Interpretation of increased values
- Pancreatic cancer (cancer of the pancreas; detectable in 70-95% of cases )
- Colon carcinoma (cancer of the colon; detectable in 75% of cases )
- Gastric carcinoma (stomach cancer; detectable in 30% of cases).
- Hepatocellular and cholangiocellular carcinoma.
- Cholangiocarcinoma (bile duct carcinoma; detectable in 55-80% of cases).
- Hepatocellular carcinoma (liver cancer; detectable in 20-50% of cases).
- Elevations (usually < 100 U/ml) also in the following benign (benign) diseases:
- Acute pancreatitis (inflammation of the pancreas).
- Hepatitis (inflammation of the liver)
- Cystic fibrosis (cystic fibrosis) – genetic disease that leads to increased production of mucus too viscous in the respiratory tract and gastrointestinal tract.
Interpretation of lowered values
- No diagnostic significance
Further notes
- Individuals with negative Lewis a/b blood group trait (3-7% of the population) are unable to form CA 19-9
- Concurrent determination of CEA increases sensitivity (percentage of diseased patients in whom disease is detected by use of the test, i.e., a positive test result occurs) in gastrointestinal tumors.