APPLICATION: The test should not be used as either a screening or diagnostic test for malignancy. It may be used to monitor effectiveness of therapy in patients with a malignancy that has been shown to produce the marker. Cancer antigen 19.9 (CA 19.9) is a marker for gastrointestinal malignancy, especially carcinoma of the pancreas.
INTERPRETATION: Persistence of an increased level after treatment indicates a significant amount of residual tumour. Decrease to a normal level after treatment may mean eradication of the tumour or persistence of only small amounts of tumour; subsequent elevation indicates regrowth of the tumour. Lesser elevations may be found in some non-malignant conditions.
