A Rapid Enzyme-Linked Immunosorbent Assay for Serum Amyloid a Using Sequence-Specific Antibodies

A microtitre plate based enzyme-linked immunosorbent assay for determining the concentration of serum amyloid A (SAA) is described. The method employs easily produced sequence-specific rabbit antibodies and the preferential absorption of SAA to polystyrene, which obviates the use of capture antibodies and allows an assay time of only 3 · 5 h, so that the diagnostic potential of the SAA level as a rapid and reliable marker for inflammation can be fully exploited. The assay has a working concentration range of 0·1–2500 mg/L, which embraces the known biological variation of the SAA concentration. The intra-assay coefficient of variation (CV) for SAA concentrations above 10 mg/L is between 1 · 6 and 3·3% and the inter-assay CV between 3·0 and 4·2%. Recovery of SAA added to serum is from 96 to 102%.