Carcinoembryonic Antigen (CEA) analysis is a blood test used to measure the level of CEA in the blood, which is a protein typically produced in fetal tissues during pregnancy. Although this protein is considered normal in children and fetuses, CEA levels can rise in certain cancer cases, such as colon, breast, lung, and stomach cancers, as well as some non-cancerous conditions like inflammatory bowel disease or lung disorders. CEA analysis is primarily used as a tool to monitor patients who have already been diagnosed with specific types of cancer. It helps evaluate the patient's response to treatment, as low CEA levels may indicate effective treatment, while elevated levels could suggest disease progression or relapse. It is important to note that an elevated CEA level is not entirely specific to cancer, as increases can also occur in some non-cancerous conditions. Therefore, CEA test results should always be used alongside a thorough evaluation of the patient's medical history and other tests for an accurate assessment of their condition.