Establishment of a Microcapsule Agglutination Test for Serodiagnosis of Leptospirosis

A passive microcapsule agglutination test (MCA-LS) for serodiagnosis of leptospirosis, utilizing chemically stable microcapsules instead of sheep erythrocytes, was developed by the author. In the test, sonically disrupted antigens of leptospira cells were sensitized to microcapsules treated with glutaraldehyde. In comparison with the microscopic agglutination test, the MCA-LS showed a relatively group-specific tendency and a 2- to 32-fold-higher sensitivity. This new test, conducted on IgM and IgG gel-filtered fractions of leptospirosis patient sera, proved that the sensitized microcapsule antigen reacted sharply with the IgM antibodies. The microcapsules coupled with mixed antigens can be used as a serodiagnostic screening test for diseases caused by various serovars of leptospira. The test, which is very simple and reproducible and requiring no specific training, can be employed easily as a routine test in diagnostic laboratories. The sensitized microcapsule antigens were stable for at least 1 year when stored at 6℃±2℃