[Determination of carcinoembryonic antigen in medical practice].

108 determinations of CEA plasma concentrations were ordered for diagnostic purposes by the medical staff of our clinic between January 1974 and April 1976. Its usefulness was retrospectively analyzed by comparing the initially suspected diagnosis serving as the rationale for CEA determination with the CEA plasma levels and the final diagnoses of the patients when leaving the hospital. Of 32 patients with proven malignancies of various types the CEA concentrations were normal in 10, slightly elevated (2.5-20.0 ng) in 15, and highly elevated in 7, all having metastatic tumors. However, in 35 of the remaining 67 tested individuals without detectable malignancies the CEA concentrations were also slightly elevated (2.5-20.0 ng); these patients either had acute infections (10 individuals), autoimmune disease disorders (1 individual), various other nonmalignant diseases (10 individuals), or were heavy smokers. In 98 of 108 patients CEA testing had been ordered either to confirm or to rule out a suspected malignancy. The results were most often of little help. Malignancies were found in 15 of 50 patients with elevated CEA, but also in 9 of 48 patients with normal values. In only 6 patients did the CEA results influence further diagnostic and/or therapeutic measures, which consequently did not always prove to be beneficial for the patient.