Abstract
The indirect hemagglutination test using tanned formalinized sheep erythrocytes was investigated for serodiagnosis of leptospirosis. The leptospiral antigens for the hemagglutination test were extracted with sodium deoxycholate. Sera obtained about the 2nd week of leptospirosis had positive hemagglutination titers of 1:12, 800 or higher against five leptospiral types, and most sera from healthy individuals and syphilitic sera did not agglutinate at 1:100. The antigens extracted with sodium deoxycholate remained serologically reactive for at least one year when kept in aqueous suspensions at 4°C. The test was observed to be a useful diagnostic procedure.
