A CA 19-9 blood test measures the level of CA 19-9, a protein, in your blood. This protein is a tumor marker, meaning it's a substance produced by some cancer cells or by normal cells in response to cancer. While often associated with pancreatic cancer monitoring, elevated levels can also be seen in other cancers and even some benign conditions.
What does the CA 19-9 test measure?
The test quantifies the amount of CA 19-9 protein present in a blood sample. High levels may indicate the presence of cancer, but it's crucial to remember that this isn't a definitive diagnostic tool on its own.
What cancers is CA 19-9 associated with?
CA 19-9 is most commonly used to monitor pancreatic cancer, but elevated levels can be observed in several other cancers, including:
- Stomach cancer
- Bile duct cancer
- Colon cancer
Is CA 19-9 useful for diagnosis?
The CA 19-9 test is not typically used for initial cancer diagnosis. Instead, it's primarily used to:
- Monitor the progression of known pancreatic cancer
- Assess the response to treatment for pancreatic cancer and other cancers.
- Help differentiate pancreatic cancer from other conditions, although it is not always conclusive.
It's important to note that many non-cancerous conditions can also cause elevated CA 19-9 levels. These include:
- Pancreatitis
- Liver disease
- Certain intestinal disorders
- Blockages in the bile ducts
Therefore, a high CA 19-9 level requires further investigation with other diagnostic tools to determine the underlying cause.
Interpretation of Results
The interpretation of CA 19-9 test results should always be done in conjunction with a physician and considers other clinical factors. The reference range varies slightly between labs, so it's essential to check the specific range provided by your healthcare provider. An elevated level does not automatically mean cancer, and a normal level does not guarantee the absence of cancer.
