CEACAM5 and intestinal cancer: Sensitivity and specificity are low, so this test is often used for monitoring during and after treatment rather than for screening or diagnosis.135 Tracked monitoring of carcinoembryonic antigen level in a patient’s blood sample can be useful for understanding the prognosis and response to treatment.11,70 Complete blood count is often used alongside other tests as its levels can be normal in patients with bowel cancer or abnormal in many other conditions.