Enzyme immunoassay for the measurement of human tenascin-C on the Bayer Immune 1 (TM) analyzer

Objectives: To evaluate a new tenascin-C assay performed on the Payer Immun e 1(TM) system. Design and methods: The precision was measured using three levels of serum pools. Linearity was tested by diluting patient serum samples containing hi gh tenascin-C concentrations, and the minimal detectable concentration dete rmined by repetitive analysis of the zero calibrator. Preliminary reference intervals were determined by testing serum samples from 220 healthy indivi duals. Biovariability was estimated in a cohort of 20 apparently healthy su bjects over 18 days. The levels of tenascin-C in patients with different li ver diseases was tested. Results: The detection limit was 2 ng/mL. At concentrations ranging from 32 5 to 1957 ng/mL the assay demonstrated within-run and between-run CVs rangi ng from 4% to 3.6% and 8.4% to 6.7%, respectively. Dilutions of sera were l inear and parallel to the standard curve with recoveries ranging from 97% t o 100%. The reference interval (central 95% interval) for tenascin-C in ser um of healthy adults was 199-906 ng/mL. The variability study yielded an an alytical variability, CVA, of 1.8%; a within-subject variability, CVI, of 1 1.7%; and a between-subject variability, CVG, of 39.3%. Tenascin-C concentr ations in sera of liver disease patients were significantly increased. Conclusions: The novel assay provides a rapid and reliable procedure for th e determination of tenascin-C levels in human sera. Copyright (C) 2000 The Canadian Society of Clinical Chemists.