ANALYTICAL AND CLINICAL-EVALUATION OF A PROCEDURE FOR MEASURING CA-15-3 IN THE IMX-ANALYZER

CA 15-3 is the most widely used tumour marker in the followup of patie nts with breast cancer. Its postoperative blood level is closely relat ed to the response to the treatment applied and to the evolution of th e disease. In this study, we assessed both the clinical and analytical features of a new microparticle enzyme immunoassay for CA 15-3 quanti fication in the Abbott IMx system. In the precision study, the coeffic ients of variation within runs, between runs and between laboratories were 3.5, 5.1 and 6.5% or less, respectively. The analytical sensitivi ty of the assay was 0.11 U/ml. Linear regression analyses of the IMx C A 15-3 assay with the Centocor and CIS CA 15-3 RIAs gave correlation c oefficients of 0.88 and 0.95, respectively. The upper limit of the ref erence range, obtained from serum of healthy women, was 27.3 U/ml, whi le the ROC curve analysis for patients with active breast cancer compa red to patients with no evidence of the disease gave an optimum cut-of f of 33 U/ml (sensitivity 0.76 and specificity 0.87). The overall agre ement of the three methods was over 90%.