[Determination of carcinoembryonic antigen (CEA) in patients with tumors of the large intestine. Experience with a new radioimmunoassay (author's transl)].

Specimens from 93 patients with histologically confirmed tumors of the large bowel (53 single, 40 sequential determinations) were investigated by a new CEA radioimmunoassay (double antibody method, direct serum determination). Of the single and preoperative sequential determinations 37-40% were normal (below 2.5 ng/ml), one third was intermediately elevated (2.6-15 ng/ml) and 26-28% were highly pathological leveled (over 15 ng/ml). Following operation, cases with local or regionally confined tumor showed significantly more normal or normalizing CEA levels within 1-6 weeks (17/27), whereas patients with overt metastases developed more pathological or increasingly pathological levels (8/11).