Evaluation of the Indirect Hemagglutination Assay for Diagnosis of Acute Leptospirosis in Hawaii

Abstract

Timely diagnosis of leptospirosis is important to ensure a favorable clinical outcome. The definitive serologic assay, the microscopic agglutination test (MAT), requires paired sera and is not useful for guiding early clinical management. The only screening test approved for use in the United States, the indirect hemagglutination assay (IHA), has not undergone extensive field evaluation. To assess the performance of the leptospirosis IHA in Hawaii, serum from patients evaluated for leptospirosis between 1992 and 1997 were tested with the IHA at the Hawaii State Laboratories Division and with the MAT at the Centers for Disease Control and Prevention. Leptospirosis was considered confirmed by a fourfold rise in MAT titer and/or a positive culture. A total of 92 (41%) of 226 specimens from 114 persons with confirmed leptospirosis were found positive by IHA. Only 18 (15%) of 119 specimens obtained within 14 days of onset were IHA positive, compared to 74 (69%) of 107 specimens collected more than 14 days after onset (P <0.001). Repeat testing ultimately resulted in 78 (68%) of the confirmed cases having at least one specimen found positive by IHA. Thirteen different presumptive infecting serogroups were identified among 251 specimens with an MAT titer of ≥200 and obtained from persons with confirmed or probable leptospirosis. Fifty (68%) of 73 specimens with Icterohaemorrhagiae as the presumptive infecting serogroup were found positive by IHA, compared to 44 (47%) of 93 specimens with Australis as the presumptive infecting serogroup (P, 0.01). The IHA test was positive for 3 (1%) of 236 specimens from 154 persons without leptospirosis. The sensitivity of the leptospirosis IHA in Hawaii was substantially below figures reported previously, particularly early in the course of illness, limiting its usefulness for diagnosing acute infection. Since the presumptive infecting serogroup affected IHA results and the prevalence of serovars varies with geography, the performance of the IHA should be assessed locally. More sensitive leptospirosis screening tests are needed in Hawaii.

Evaluation of the EIE-IgM-Leptospirose assay for the serodiagnosis of leptospirosis

“…The evaluation found that the EIE-IgM Leptospirose achieved similar performance characteristics as those reported for whole Leptospira-based serologic assays (Bajani et al, 2003, Effler et al, 2000, Levett and Branch, 2002, Sehgal et al, 2003, Smits et al, 2001a, Smits et al, 2001b, Vijayachari et al, 2002. This is not surprising for although the serovar source and preparation of antigen used in these assays may differ, they appear to detect an antibody response against the same immunodominant moiety, "broad reactive antigen" (Faine et al, 1999, Terpstra et al, 1985 which is expressed in the spectrum of pathogenic serovars.…”

“…However these numbers significantly underestimate the true disease burden since (i) leptospirosis often goes unrecognized because of its non-specific presentation (Johnson et al, 2004, Murdoch et al, 2004, Russell et al, 2003, Segura et al, 2005, being misdiagnosed as dengue (Flannery et al, 2001, Karande et al, 2005, LaRocque et al, 2005, malaria (Ellis et al, 2006, Wongsrichanalai et al, 2003 or other causes of acute febrile illness, and (ii) standard diagnosis is based on antiquated methods, the microscopic agglutination test (MAT) and culture isolation, which are performed in few reference laboratories worldwide (Faine et al, 1999, WHO, 2003. Whole Leptospira-based serologic tests in ELISA and rapid formats are commercially-available and have a sensitivity of 28-72% and 75-94% to detect acute and convalescent-phase illness respectively (Bajani et al, 2003, Effler et al, 2000, Levett and Branch, 2002, Sehgal et al, 2003, Smits et al, 2001a, Smits et al, 2001b, Vijayachari et al, 2002. Limited access to effective diagnosis, especially in developing countries where the disease burden is greatest, is a major cause of under-reporting, which in turn has contributed to the perception of leptospirosis as a neglected disease.…”

Latex based, rapid and easy assay for human leptospirosis in a single test format

“…In these circumstances relatively simple assays such as the haemagglutination assay (Levett & Whittington 1998) may be used, but this assay has a limited sensitivity for samples collected early in the disease (Ef¯er et al 2000). Stability of assay reagents is an important prerequisite for tests used in tropical countries, and we recently described a dipstick assay (Gussenhoven et al 1997;Smits et al 1999;2000) and a latex agglutination test (Smit et al 2000b) for the detection of Leptospira-speci®c antibodies in human sera. The latex agglutination assay is performed by mixing on an agglutination card 5 ll serum with 5 ll antigen-coated, dyed latex beads.…”

“…However, laboratory facilities to perform such complicated and time‐consuming tests are rarely available in endemic areas. In these circumstances relatively simple assays such as the haemagglutination assay ( Levett & Whittington 1998) may be used, but this assay has a limited sensitivity for samples collected early in the disease ( Effler et al . 2000 ).…”

Short communication: Comparison of serology and isolates for the identification of infecting leptospiral serogroups in Hawaii, 1979–1998

“…The wide geographic variability in infecting serogroups make interpretation of MAT results suspect without broad in‐depth knowledge of locally enzootic and endemic serogroups (Effler et al. 2000).…”