This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Setiyono, A. Articles by Kurane, I. Search for Related Content PubMed PubMed Citation Articles by Setiyono, A. Articles by Kurane, I.

New Criteria for Immunofluorescence Assay for Q Fever Diagnosis in Japan

Laboratory of Rickettsia and Chlamydia,¹ Department of Virology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-Ku, Tokyo 162-8640, Japan,² Laboratory of Pathology, Department of Parasitology and Pathology, Faculty of Veterinary Medicine, Bogor Agricultural University, Jl. Agatis, Kampus IPB Darmaga Bogor 16680, Indonesia³

Received 26 October 2004/ Returned for modification 24 January 2005/ Accepted 9 August 2005

A study was made to evaluate the cutoff value of indirect immunofluorescent-antibody (IFA) test for Q fever diagnosis in Japan. We used 346 sera, including 16 from confirmed Q fever cases, 304 from Japanese pneumonia patients, and 26 from negative cases. Thirteen sera from the confirmed Q fever cases with an immunoglobulin M (IgM) titer of 1:128 and/or IgG titer of 1:256 by the IFA test were positive by both enzyme-linked immunosorbent assay (ELISA) and Western blotting assay (WBA), whereas 298 sera from pneumonia patients and 26 negative sera with an IgM titer of 1:16 and an IgG titer of 1:32 by the IFA test were negative by both ELISA and WBA. In the proposed "equivocal area," with an IgM titer of 1:32 and 1:64 and/or an IgG titer of 1:64 and 1:128, we found 9 sera, 3 from confirmed Q fever cases and 6 from Japanese pneumonia patients, by the IFA test. Three sera from the confirmed Q fever cases and one of the sera from pneumonia patients were IgM and/or IgG positive by both ELISA and WBA. These results suggest that a single cutoff value for the IFA test may cause false-positive and false-negative results. In conclusion, this study showed that an "equivocal area" should be used for the IFA test rather than a single cutoff value and that sera in the equivocal area should be tested by additional serological assays for confirmation.

This article has been cited by other articles:

• Vaidya, V. M., Malik, S. V. S., Kaur, S., Kumar, S., Barbuddhe, S. B. (2008). Comparison of PCR, Immunofluorescence Assay, and Pathogen Isolation for Diagnosis of Q Fever in Humans with Spontaneous Abortions. J. Clin. Microbiol. 46: 2038-2044 [Abstract] [Full Text]