Serodiagnosis of human leptospirosis by counterimmunoelectrophoresis.

The counterimmunoelectrophoresis (CIE) technique employing a soluble extract antigen was found useful in screening human sera for antileptospiral antibodies to multiple leptospiral serovars. The CIE test results with sera from patients with suspected cases of leptospirosis and sera from a control group compared favorably (97.9%) with those obtained by the microscopic agglutination test using a battery of live leptospiral antigens. CIE is easy to perform, is highly sensitive, uses an antigen which is very stable at room temperature, and permits the screening of many sera in a short period of time. The CIE technique appears to be ideally suited to a small laboratory where facilities may be too limited for examining sera by the microscopic agglutination test.