CPT® Code 86301

A quantitative immunoassay for tumor antigen CA 19-9 is a laboratory test that measures the levels of the CA 19-9 antigen in the blood or other body fluids. Tumor antigens, commonly known as tumor markers, are substances that can indicate the presence of a malignant neoplasm, or cancer. The presence of significant levels of CA 19-9 in the serum is often associated with malignancies, particularly those affecting the pancreas, colon, stomach, or biliary system. This test is particularly valuable for monitoring the response to treatment in patients who have already been diagnosed with these types of cancers. The CA 19-9 test employs an electrochemiluminescent immunoassay test kit, which is a sophisticated method that enhances the sensitivity and specificity of the measurement. It is important to note that if the test is conducted on body fluids other than blood, the specific source of the fluid must be clearly identified. Regular testing of tumor antigens like CA 19-9 is typically used alongside other clinical assessments to evaluate the progression or regression of cancer, providing critical information for ongoing patient management.