Plasma Carcinoembryonic Antigen in an Australian Hospital Population*

Plasma carcinoembryonic antigen (CEA) levels have been determined by the zirconyl phosphate gel (Z-gel) method, using materials provided by Hoffman-LaRoche Inc., on 512 samples from 425 hospital patients, and on single samples from 124 normal controls (98 blood donors and 26 healthy staff members). Of the controls, 98% had CEA levels less than 5 ng/ml. Forty-six hospital patients had CEA levels above 20 ng/ml; 45 (98%) had known present or past cancer. Nineteen patients had levels between 10 and 20 ng/ml; 11 (58%) had present or past cancer. Sixty-seven patients had levels between 5 and 10 ng/ml, and most of these had non-malignant diseases; only 34% had present or past cancer. Cigarette smoking was associated with elevated CEA levels among patients with non-neoplastic diseases, notably those with cirrhosis of the liver and chronic renal disease. There was a gradation of increasing specificity for cancer with increasing levels of CEA from 5 to over 20 ng/ml; but, on the other hand, higher levels were associated with more disseminated cancer, which would be less amenable to cure.