SAT, DRI -DOT, I GM-ELISA AND MAT FOR LEPTOSPIROSIS DIAGNOSIS Vol 38 No. 6 November 2007 1111 Correspondence: Chintana Chirathaworn, Depart- ment of Microbiology, Faculty of Medicine, Chulalongkorn University, Rama IV, Bangkok 10330, Thailand. Tel: 66 (0) 2256-4132 E-mail: chintana_chula@yahoo.co.th RESEARCH NOTE COMPARISON OF A SLIDE AGGLUTINATION TEST, LEPTOTEK DRI-DOT, AND I GM-ELISA WITH MICROSCOPIC AGGLUTINATION TEST FOR LEPTOSPIRA ANTIBODY DETECTION Chintana Chirathaworn 1 , Yada Kaewopas 1 , Yong Poovorawan 2 and Duangjai Suwancharoen 3 1 Department of Microbiology, 2 Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok; 3 National Institute of Animal Health, Department of Livestock Development, Bangkok, Thailand Abstract. A slide agglutination test (SAT), LeptoTek Dri-Dot and IgM-ELISA were compared with a microscopic agglutination test (MAT) for the detection of Leptospira antibodies. Paired sera from 10 patients whose leptospirosis was clinically suspected and diagnosed by MAT, were evaluated in this study. Our data, especially from acute samples, demonstrate the SAT and Dri-Dot were more sensitive as initial screening tests than MAT. IgM-ELISA has an advan- tage over MAT, SAT, and Dri-Dot since the results can be interpreted from a single serum testing if the results of the test are positive. Eight of the ten cases could be diagnosed by IgM- ELISA. Our data suggest that IgM-ELISA may be used for the diagnosis of leptospirosis. How- ever, the agglutination test is useful for screening and for secondary infection cases for which IgM antibodies may be undetectable. MAT can be performed as a reference test and when information regarding the causative serovar is required. when MAT is often not available. Various sero- logical diagnostic assays, sush as macroscopic agglutination, indirect hemagglutination, ELISA, dot-ELISA and dipstick assays, have been de- veloped (Brandão et al, 1998; Tirawatnapong et al , 1999; Chirathaworn et al , 2001; Vijayachari et al, 2002; Bajani et al, 2003; Vitale et al, 2004 ; Boonyod et al, 2005; Ooteman et al, 2006). ELISA is a technique known for its sensitivity and specificity. The subclasses of im- munoglobulin can be identified by this tech- nique. Detection of IgM antibody specific to an organism suggests acute infection. Assays that cannot identify subclasses of immunoglobulin, such as the MAT and slide agglutination test (SAT), require paired sera to demonstrate in- fection is caused by the suspected organism. However, assays based on the agglutination technique have been widely used since they INTRODUCTION Leptospirosis is a zoonosis in which the symptoms vary from subclinical infection to severe or fatal illness. Conventional laboratory diagnosis is based on serological assays since the successful Leptospira culture rate is very low. The microscopic agglutination test (MAT) is the reference serological assay. However, MAT is a laborious and time consuming tech- nique (Ahmad et al, 2005; McBride et al, 2005). A highly specific, rapid, easy to perform test is needed since leptospirosis occurs in areas