Reverse passive hemoagglutination for detection of clostridium difficile toxin B

A toxin-producing strain of clostridium difficile was anaerobically cultured in dialysis flasks. The culture supernatant was applied to filtrate chromatography and ion exchange chromatography sequentially. The toxin B was purified and was then used to immunize rabbits for antiserum. A reverse passive hemoagglutination （RPHA） was established, using the sheep red blood cells sensitized by the antibody. After 137 samples were tested, the RPHA assay showed the specificity and sensitivity of 88.9% and 87.2% respectively, as compared with tissue culture assay results. The detecting limit for purified toxin B was 78ng/ml. The test can be used as a screening test for a clinical lab.