Factors affecting the radioimmunological determination of carcinoembryonic antigen in human plasma
Wagener, C.; Breuer, H.
Journal of Clinical Chemistry and Clinical Biochemistry 16(11): 601-605
1978
ISSN/ISBN: 0340-076X PMID: 731192 Document Number: 124773
Two commercially available test kits for the determination of carcinoembryonic antigen (CEA) in human plasma were compared with various experimental conditions: an indirect method (Hoffmann-La Roche), in which the plasma sample is extracted by perchloric acid, and a direct method (CEA-IRE-SORIN) without prior treatment of the plasma. Using plasma from cancer patients, the CEA values obtained by the direct method were about 5 times higher than those determined by the indirect procedure. This result is primarily due to the quantitative differences between the different standard preparations. Perchloric acid had significantly less influence. The standard buffer of the CEA-IRE-SORIN assay did not affect the level of plasma CEA; when the standard buffer of the Hoffmann-La-Roche assay was used, the CEA values were lower when compared with a buffer with a protein composition similar to that of the sample. A standardized method with an internationally accepted CEA standard is required for the quantitative determination of CEA.