Rapid enzyme immunoassay for quantification of C-reactive protein (CRP).

A simple, rapid enzyme immunoassay (EMIT CRP assay) for C-reactive protein (CRP) was assessed using human acute phase sera and purified human CRP. The calibration curve was established from 10 micrograms/mL to 150 micrograms/mL. The precision evaluations of the assay, carried out under optimal conditions of the test, (CRP levels: 20-100 micrograms/mL) showed coefficients of variation less than 7%, both for within-run and day-to-day precision. The limit of sensitivity was 10 micrograms/mL. The coefficients of correlation with radial immunodiffusion and immunonephelometry were respectively 0.988 and 0.956. The dilution assay showed a linear response. No significant changes in the CRP level were observed after sample storage either at 4 degrees C or -20 degrees C for 3 to 10 days, or after removing lipoproteins from sera. The EMIT CRP assay is characterized by its short assay time, its excellent precision, and its sensitivity is sufficient to detect an ongoing inflammatory process.