[The CEA-concentration in plasma of patients with colorectal carcinoma and polyps has been determined by radioimmunoassay (RIA, Z-gel-method)].

82% of the cancer patients and 52% of the patients with polyps showed CEA levels above the upper normal limit of 2,5 microgram/1. CEA-values of more than 10 microgram/1 could only be detected in patients with carcinoma. Complete removal of the tumour by surgery has been followed by a marked decrease of prior increased plasma-CEA to values in the normal range, which could not be observed in the cases with tumour residues or metastases. In the patient's follow-up recurrence or metastases could be recognized several months before clinical detection by a renewed increased of the CEA-level in plasma.