CA 19-9 test is performed to measure the amount of a protein called CA 19-9 in your blood sample. This test is often done as a panel of tests to detect early-stage cancer. CA 19-9 is a commonly used marker for pancreatic ductal adenocarcinoma, malignant cancer that accounts for 80 percent of pancreatic cancer cases. Many patients with gastrointestinal tumours like gastric, colorectal, pancreatic, liver, tumours, and other malignancies have been identified with elevated serum CA 19-9 levels. Several benign conditions can also lead to increased CA 19-9 levels.

CA 19-9 test provides important details about the progression and presence of cancer. The doctor may order this test to monitor your response to treatments and medications. This test can also be used to watch for a relapse of cancer. It is also important to understand that the CA 19-9 test alone cannot be used to detect the presence of pancreatic cancer, but it can be used with other biomarkers on a panel that can signal the presence of this disease.

What is CA 19-9 Test?

CA 19-9 test is performed to measure the amount of a protein called CA 19-9 in your blood sample. This test is often done as a panel of tests to detect early-stage cancer. CA 19-9 is a commonly used marker for pancreatic ductal adenocarcinoma, malignant cancer that accounts for 80 percent of pancreatic cancer cases. Many patients with gastrointestinal tumours like gastric, colorectal, pancreatic, liver, tumours, and other malignancies have been identified with elevated serum CA 19-9 levels. Several benign conditions can also lead to increased CA 19-9 levels.

CA 19-9 test provides important details about the progression and presence of cancer. The doctor may order this test to monitor your response to treatments and medications. This test can also be used to watch for a relapse of cancer. It is also important to understand that the CA 19-9 test alone cannot be used to detect the presence of pancreatic cancer, but it can be used with other biomarkers on a panel that can signal the presence of this disease.

What is the Purpose of the CA 19-9 Test?

CA 19-9 test measures the level of CA 19-9 in your blood. It can also be used to detect pancreatic cancer. After the diagnosis of pancreatic cancer, the CA 19-9 test can also be used to watch the disease's development. This test is only effective if the tumour creates enough of the CA 19-9 marker, so it is mostly ordered with other tests that measure the liver and pancreas' functioning. Some people don't make CA 19-9 even after having cancer which usually produces high CA 19-9 levels.

What Does CA 19-9 Test Diagnose?

CA 19-9 test can be used to diagnose certain types of cancer. The doctor may also order this test after the diagnosis of pancreatic cancer. If your CA 19-9 level was raised before pancreatic cancer treatment, you might be tested after and during treatment to analyse the success. Certain non-cancerous conditions like biliary infection, liver disease, gallstones, cystic fibrosis, and blockage of the bile duct can also cause high CA 19-9 levels.

Changes in CA 19-9 levels can help the doctor see if the tumour is staying the same, growing, or getting smaller. This can also help your doctor decide whether to change treatment or run more scans or tests. 

Why Do You Need a CA 19-9 Test?

CA 19-9 test is used to monitor different types of cancer like bile duct, stomach, ovaries, rectum, colon, and bladder. It can also help predict how cancer will progress over time. You may also need a CA 19-9 test if you have been diagnosed with certain types of cancer that elevate the level of CA 19-9. During cancer treatment, your doctor may order this test to see if the treatment is working. You may need this test after the cancer treatment is complete to see if the cancer has come back. If you had any surgery, you might be ordered CA 19-9 tests as part of your follow-up care.

Preparation and Procedure Required for a CA 19-9 Test

No specific preparations are needed for a CA 19-9 test. You don't need to fast before this test. But you must inform your doctor about the medications you're taking as certain medications can alter the test results. You should also follow the instructions of the doctor and the technician before this test.

To perform the CA 19-9 test, the technician will insert a small needle in the vein of the patient's arm. You may feel a prickling sensation or slight pain when the needle is inserted. Once the blood is drawn, a cotton pad will be applied over the wound. The blood sample will be sent to the laboratory for further analysis. Because different ways are used by the labs to measure CA 19-9 levels, you should ask the technician which method will be used to test your CA 19-9 levels.

Understanding CA 19-9 Test Results

The normal CA 19-9 range is between 0 and 37 units per millilitre in an average person. Many people can have low CA 19-9 levels in their blood. Low CA 19-9 levels are generally considered normal if no organ distress or cancer signs and symptoms exist. Declining CA 19-9 antigen levels may indicate the tumour is getting smaller and treatment is effective. A decline in the CA 19-9 antigen level followed by an increase indicates the tumour has become larger or returned.

When high CA 19-9 levels are discovered on the blood test, this may be an indication of malignancy. 95% of pancreatic cancer patients have high CA 19-9 levels. But it is important to note that certain other diseases and cancers can also simulate the results. The CA 19-9 test alone can't be used as a tool for the screening of cancer. A CA 19-9 test is only one part of a comprehensive cancer screening. Tumour marker tests, along with other blood tests, diagnostic imaging tests, and physical examinations, are needed to accurately assess the patient's condition.