Bentonite, Latex, and Cholesterol Flocculation Tests for the Diagnosis of Trichinosis

AT THE Communicable Disease Center of the Public Health Service the bentonite flocculation test (BFT) is used routinely for the diagnosis of trichinosis. This test has been under continual evaluation for sensitivity and specificity since 1952. As part of this evaluation and to keep abreast of new developments, we have attempted, whenever possible, to compare the BFT with new tests and reagents as they have become commercially available. The trichinalatex antigen sold by Hyland Laboratories has been tested intensively. The antigen for the Suessenguth and Kline flocculation test marketed by the LaMotte Company and the reagents for a bentonite flocculation test and a latex test prepared by the Difco Laboratories have received limited evaluations. The accumulated results of our studies may be of help to local laboratories in interpreting their tests. They do not constitute an endorsement or rejection of the proiducts examined. Several particle agglutination tests have been used for the diagnosis of trichinosis. Suessenguth and Kline (1) adapted the Kline test for syphilis to a test for trichinosis and used cholesterol particles Icoated with various trichina antigens. They reported high sensitivity for both human and animal trichinosis (2-4). Campbell (5) and Coudert and Coly (6) used coated collodion particles, and Leikina and Poliakova (7), carmin particles in their tests. Vogel and co-workers (8) employed cholesterollecithin particles. Bozicevich and associates (9) introduced the use of bentonite particles. A series of papers from the CDC. laboratory has reported evaluations of the bentonite test for detection of infection in pigs (10) and in humans (11). The efficacy of Melcher's antigen (13) and of metabolic antigen (12) has been reported as well as that of lyophilized reagents (14). Innella and Redner (15) were the first to describe the use of latex particles coated with trichina antigen. Their test was essentially a modification of the latex test for rheumatoid arthritis developed by Singer and Plotz (16). Muraschi and co-workers have been using the latex test since 1957 and recently published their evaluation of a slide latex-particle agglutination test for trichinosis (17).