The effect of serum protein concentrations on the specificity of the radioimmunoassay of carcinoembryonic antigen in malignant neoplasia and non-neoplastic disease.

Carcinoembryonic antigen (CEA) has been measured in parallel with seven serum proteins and seromucoids in the sera of patients with malignant neoplasia and non-neoplastic disease. In the total group significant correlations were found between CEA and seromucoids and between CEA and several serum proteins. However, with two exceptions, when the individual disease groups were examined no correlation was seen. It is concluded that abnormal concentrations of the specific proteins measured do not consistently interfere in the CEA radioimmunoassay and do not explain the high CEA levels in patients with non-neoplastic diseases.