Latex agglutination test: a simple, rapid and practical method for bovine serum CRP determination

A semi-quantitative latex agglutination test for bovine serum CRP levels has been established by mixing diluted serum (or diluted standard serum) with a 1% latex suspension containing 0.489 micron latex particles coated with affinity-purified antibody at a ratio of 20 micrograms/mg latex. The agglutination was performed on a glass slide in a moist chamber at room temperature with 45 min. incubation. This test is reliable, reproducible and the results correlate with those of the single radial immunodiffusion (SRID) test. The effect of low temperature storage on CRP concentration revealed a 30% degradation of CRP during 2 years storage at 4 degrees C. The possible role of EDTA addition to prevent a decrease in serum CRP concentration by freezing and thawing is also discussed.