title: Proficiency testing for the radioimmunoassay of carcinoembryonic antigen. A one-year report.
abstract: Forty-three laboratories participated in an interlaboratory testing program offered by the College of American Pathologists for the radioimmunoassay (RIA) of carcinoembryonic antigen (CEA). Thirty correctly reported a sample with 1.9 ng of endogenous CEA per ml as less than 2.5 ng. For samples with added exogenous CEA at the 5.4 ng/ml level, 24 laboratories reported too low and six too high (more than 2 SD beyond the targe value). At the 8.9 ng/ml concentration, three laboratories underestimated the CEA, while 18 overestimated the sample's concentration. A similar proportion of the laboratories performed in the same manner when estimating CEA at a target concentration of 15.9 ng/ml (five underestimating and 27 overestimating the concentration). Although individual variations were large, the majority of participating laboratories can reliably distinguish normal concentrations of CEA from moderate, intermediate and large elevations.
mesh_terms: D002272:Carcinoembryonic Antigen / Q000032:analysis*; D006801:Humans; D011786:Quality Control; D011863:Radioimmunoassay / Q000592:standards*; D014481:United States
chemical_list: D002272:Carcinoembryonic Antigen