The CA 72-4 test measures the level of cancer antigen 72-4, a tumor-associated glycoprotein found in the blood. It serves primarily as an adjunct biomarker for evaluating and monitoring gastrointestinal malignancies, most notably gastric (stomach) cancer, as well as tracking potential disease recurrence or treatment efficacy. Additionally, CA 72-4 is sometimes utilized alongside other markers, such as CA 125, in the management of ovarian and other epithelial cancers. Because elevated concentrations can also occur in benign inflammatory conditions, the test is not used for standalone screening and requires correlation with clinical findings.