Detection of fecal blood by colloidal gold agglutination using an anti-human hemoglobin monoclonal antibody.

Monoclonal antibodies to human hemoglobin were produced and a colloidal gold agglutination method has been developed for detection of fecal occult blood. Since hemoglobin is composed of the tetramer, alpha 2 beta 2, a single monoclonal antibody-labeled colloidal gold can agglutinate with hemoglobin. The lowest detectable hemoglobin concentration was 0.5 micrograms/ml. A total of 785 fecal samples were determined using colloidal gold agglutination and compared with latex agglutination. The colloidal gold agglutination detected blood in 75 samples, whereas latex agglutination detected blood in 76 samples, and among them 70 were positive in both methods. Overall agreement between the two methods was 98%.