Evaluation of a CLEIA automated assay system for the detection of a panel of tumor markers.

Tumor markers are commonly used to detect a relapse of disease in oncologic patients during follow-up. It is important to evaluate new assay systems for a better and more precise assessment, as a standardized method is currently lacking. The aim of this study was to assess the concordance between an automated chemiluminescent enzyme immunoassay system (LUMIPULSE® G1200) and our reference methods using seven tumor markers. Serum samples from 787 subjects representing a variety of diagnoses, including oncologic, were analyzed using LUMIPULSE® G1200 and our reference methods. Serum values were measured for the following analytes: prostate-specific antigen (PSA), alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), cancer antigen 125 (CA125), carbohydrate antigen 15-3 (CA15-3), carbohydrate antigen 19-9 (CA19-9), and cytokeratin 19 fragment (CYFRA 21-1). For the determination of CEA, AFP, and PSA, an automatic analyzer based on chemiluminescence was applied as reference method. To assess CYFRA 21-1, CA125, CA19-9, and CA15-3, an immunoradiometric manual system was employed. Method comparison by Passing-Bablok analysis resulted in slopes ranging from 0.9728 to 1.9089 and correlation coefficients from 0.9977 to 0.9335. The precision of each assay was assessed by testing six serum samples. Each sample was analyzed for all tumor biomarkers in duplicate and in three different runs. The coefficients of variation were less than 6.3 and 6.2 % for within-run and between-run variation, respectively. Our data suggest an overall good interassay agreement for all markers. The comparison with our reference methods showed good precision and reliability, highlighting its usefulness in clinical laboratory's routine.

Evaluation of an Automated CLIA System for the Determination of Carbohydrate Antigen 19-9.

AIM: To compare analytical characteristics between two different methods, a automated chemiluminescent immunoassay (CLIA) versus a radioimmunometric assay (RIA), for the determination of carbohydrate antigen 19-9 (CA19-9). MATERIALS AND METHODS: One hundred and eighty-five blood samples from consecutively enrolled individuals (87 males and 98 females, aged 22-89 and 29-89 years, respectively) were evaluated. For both assays, a cut-off of 37 U/ml was used. RESULTS: Comparison between assays was analyzed using Passing-Bablok regression, which showed a high inter-assay correlation (r=0.926). The mean intra-assay coefficient of variation was 17.6% (range=6.1-50.7%) for the RIA (n=10 samples) and 5.2% (range=0.4-17.0%) for the CLIA assay (n=26 samples). CONCLUSION: This study showed that CLIA for CA19-9 has a good reliability on all samples analyzed and should be preferred to RIA with the aim of reducing costs, greater standardization and more harmonized results.