Quantitation of hyaluronic acid in serum with automated microparticle photometric agglutination assay

A microparticle photometric agglutination assay to quantitate hyaluronic acid (HA) in serum has been developed. The principle of the method is that hyaluronic acid binding protein covalently sensitized on microparticle surface initiates the particles to agglutinate in the presence of HA. By measuring the time-course of transmittance changes at 800 nm, due to the particles' agglutination, HA concentration is estimated as a function of the magnitude of agglutination in a fully automated immunochemistry analyzer. The analytical range for HA was found to be between 10 and 1200 ng/mL. The precision (CV) was between 3.0 and 8.4% in the intra-assay (n = 10), and 4.8 and 8.9% in the inter-assay (n = 3). The lower limit of detection was 10 ng/mL. The deviation of the linearity study indicated within 8% of expected values, and the analytical recovery was between 96.5 and 106.3%. The correlation coefficient against HA plate ELISA was 0.989 with a slope of 1.01 (n = 31).