Accurate laboratory measurement of serum C-reactive protein levels

Estimations of serum levels of the acute-phase reactant C-reactive protein (CRP) were performed by three different techniques, viz. the latex indirect agglutination (LIA) test, rocket immuno-electrophoresis (RIE) and laser nephelometry (LN), on 50 consecutive serum specimens referred to the routine serology laboratory. Of the specimens 27, 18 and 13 were positive using the LIA, RIE and LN techniques respectively. The best correlation coefficient was obtained for RIE and LN (0,9113) and the poorest for LIA and LN (0,7712). We conclude that for determination of CRP the LIA test may be useful as a screening test but must be considered poorly quantitative and prone to produce false-positive results. The most accurate techniques with regard to quantitation or RIE and LN. A combination of LIA as a screening test with subsequent quantitation with either RIE or LN is recommended.