Normal CA 19-9 (Carbohydrate antigen) in a blood test

Each laboratory must establish its own normal range for the CA 19-9 (Carbohydrate Antigen) in a blood test. These ranges depend on the makeup of the local population, the technologies used and the accuracy of the measurement. There may be also slight differences in the normal levels according to age, gender, race or ethnic origin, geographic region, diet, type of sample and other relevant status.

Your doctor will study the results along with your medical record, screenings, physical condition, symptoms and any other relevant information about your situation.

If the CA 19-9 test must be performed periodically to monitor the treatment of a cancer, such as pancreatic cancer, it is recommended to perform the tests always in the same laboratory in order to properly compare the results avoiding interferences by the methods or procedures used by different labs.

CA 19-9 (Carbohydrate antigen) is a high molecular mass (200 to 1000 kDa) glycoprotein complex present in the blood as a mucin.

CA 19-9 is synthesized by normal human pancreatic and biliary ductular cells and by gastric, colon, endometrial, and salivary epithelia.

It is a protein found elevated in the blood of patients diagnosed with gastrointestinal tumors.

The CA 19-9 (Carbohydrate antigen) is a tumor marker. It means that it raises in the presence of a malignant tumor. It is used to help evaluate the outcome of therapy for malignancies of the pancreas, colorectal or biliary tract.

The CA 19-9 test is useful in the following clinical applications:

• It is an antigen helpful in post-therapeutic monitoring of a cancer to determine the success of therapy or the presence of cancer recurrence.
• For monitoring gastrointestinal cancers, head and neck tumors, and gynecologic tumors. It is frequently used in monitoring patients diagnosed with pancreatic cancer.
• Predicts the recurrence of stomach, pancreatic, liver, and colorectal malignancies.
• Used in combination with other tumor markers it is helpful for earlier detection of recurrence and development of metastases.

In case of metastasis, values may be higher than 1000 KU/l.

The following values are considered to be normal values:

IMPORTANT: These levels are expressed in kU/l. They are an example of a healthy non-smoker man/woman of about 40 years old with no known disease and not taking any medication. The ranges can be different depending on the laboratory or on your personal circumstances.