CA 72.4 is a protein that is elevated in some cases of stomach or gastric cancer. The CA 72.4 test measures the levels of this protein in the blood. The test is not used as a screening tool for gastric cancer, but rather as a diagnostic tool in patients with symptoms or risk factors for the disease. The CA 72.4 test is often used in combination with other tests, such as endoscopy and biopsy, to diagnose gastric cancer. While elevated levels of CA 72.4 may be indicative of gastric cancer, other conditions can also cause elevated levels of the protein, such as pancreatitis, hepatitis, and other types of cancer. Therefore, it is important to interpret the test results in the context of the patient’s clinical history and other diagnostic tests.