Comparison of Immunoassays for Tumor Markers CA 19-9, CA 15-3 and CA 125: Data from an International Quality Assessment Scheme

Abstract

Data collected in the 1993 and 1994 cycles of an international external quality assessment (EQA) program and in a national multicenter collaborative study were cumulatively analyzed to evaluate the standardization of the methods currently in use for the assay of mucinous tumor markers CA 19-9, CA 15-3 and CA 125. On average the between-laboratory variability was 15.2 and 16.0 CV% for CA 15-3 and CA 125 respectively; the between-laboratory variability found for CA 19-9 was markedly worse (mean 28.3 CV%). The variability component attributable to systematic differences between different methods/kits was relatively small for CA 15-3 and CA 125 (18% and 24% of the total variability) but markedly larger for CA 19-9 (48% of the total variability). The agreement of CA 19-9 results worsened in the last few years when new nonisotopic techniques became available. The precision of the methods/kits most used in the survey ranged from 9.9 to 13.3 CV% for CA 125 and from 11.6 to 13.9 CV% for CA 15-3. For these two tumor markers the precision of the traditional IRMAs does not appear different from that of the new fully automated nonisotopic techniques. The precision of CA 19-9 methods was on average worse (from 11.7 to 19.6 CV%) although two automated systems exhibited a precision better than that of IRMAs. In conclusion, the results of this study indicate that CA 15-3 and CA 125 are satisfactorily assayed whereas CA 19-9 assay appears affected by larger differences between methods and by poorer precision of laboratories and kits.

CA 15-3 and Related Mucins as Circulating Markers in Breast Cancer

“…Since all CA 15-3 assays utilize the same two monoclonal antibodies and the same standards, good agreement should be found with the different commercially available assays. Pilo et al 35 found good agreement (r = 0•98--0•99) between five different assays using control material. Furthermore, differences in concentrations between different kits were reported to be on average less than 10%.…”

“…Pilo et al 35 found good agreement (r = 0·98--0·99) between five different assays using control material. Furthermore, differences in concentrations between different kits were reported to be on average less than 10%.…”

“…Such a rapid decline may be due to suppression of marker release from its tumour.l? Practical issues relating to the assay of CA 15-3 Performance in external quality assurance programmes In one of the few published studies describing the performance of tumour markers in external quality assessment schemes, Pilo et al 35 reported the average between-laboratory coefficient of variation (CV) for CA 15-3 as being 15•2%. This was similar to that for other tumour markers such as CA 125 (16%), CEA (15'7%) and prostate-specific antigen (PSA) (15'7%), but considerably better than that reported for either CA 19-9 (28'3%) or IX-fetoprotein (AFP) (36'7%).…”

Independent Factors Predict Supranormal CA 15-3 Serum Levels in Advanced Breast Cancer Patients at First Disease Relapse

“…However, this is partly counterbalanced by the large number of patients involved. It should be noted that the enrollment of cases with metastatic disease (many of them with heavy tumor load) may have facilitated agreement between laboratories and kits in assessing the supranormal CA 15-3 levels [31,32].…”

Detection of Circulating Tumor Cells in Patients with Breast, Prostate, Pancreatic, Colon and Melanoma Cancer: A Blinded Comparative Study Using Healthy Donors

“…Blood is one such liquid that can easily be obtained to identify the presence of cancer [17] [18]. Several markers associated with cancer are analyzed in the blood, such as CA 15-3 for breast cancer, CA 19-9 for pancreatic, stomach and bile duct cancer, CA-125 for ovarian cancer, prostrate-specific antigen for prostate cancer and carcinoembryonic antigen for colorectal cancer [19]. However, these markers have limitations, the most important being their tendency to be detectable only when the tumor-burden is severe [20].…”