Comparative evaluation of selected diagnostic assays for the detection of IgG and IgM antibody to Orientia tsutsugamushi in Thailand.

Russell E ColemanDepartment of Entomology, U.S. Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand. Russell.coleman@det.amedd.army.mil

Search for other papers by Russell E Coleman in
Current site
Google Scholar
PubMed
Close
,
Vichai SangkasuwanDepartment of Entomology, U.S. Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand. Russell.coleman@det.amedd.army.mil

Search for other papers by Vichai Sangkasuwan in
Current site
Google Scholar
PubMed
Close
,
Nantavadee SuwanabunDepartment of Entomology, U.S. Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand. Russell.coleman@det.amedd.army.mil

Search for other papers by Nantavadee Suwanabun in
Current site
Google Scholar
PubMed
Close
,
Chirapa EamsilaDepartment of Entomology, U.S. Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand. Russell.coleman@det.amedd.army.mil

Search for other papers by Chirapa Eamsila in
Current site
Google Scholar
PubMed
Close
,
Siriporn MungviriyaDepartment of Entomology, U.S. Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand. Russell.coleman@det.amedd.army.mil

Search for other papers by Siriporn Mungviriya in
Current site
Google Scholar
PubMed
Close
,
Peter DevineDepartment of Entomology, U.S. Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand. Russell.coleman@det.amedd.army.mil

Search for other papers by Peter Devine in
Current site
Google Scholar
PubMed
Close
,
Allen L RichardsDepartment of Entomology, U.S. Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand. Russell.coleman@det.amedd.army.mil

Search for other papers by Allen L Richards in
Current site
Google Scholar
PubMed
Close
,
Denise RowlandDepartment of Entomology, U.S. Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand. Russell.coleman@det.amedd.army.mil

Search for other papers by Denise Rowland in
Current site
Google Scholar
PubMed
Close
,
Wei-Mei ChingDepartment of Entomology, U.S. Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand. Russell.coleman@det.amedd.army.mil

Search for other papers by Wei-Mei Ching in
Current site
Google Scholar
PubMed
Close
,
Jetsumon SattabongkotDepartment of Entomology, U.S. Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand. Russell.coleman@det.amedd.army.mil

Search for other papers by Jetsumon Sattabongkot in
Current site
Google Scholar
PubMed
Close
, and
Kriangkrai LerdthusneeDepartment of Entomology, U.S. Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand. Russell.coleman@det.amedd.army.mil

Search for other papers by Kriangkrai Lerdthusnee in
Current site
Google Scholar
PubMed
Close

We compared the performance of 2 commercially available dipstick assays, 2 enzyme-linked immunosorbent assays (ELISAs), and an indirect immunofluorescent antibody (IFA) assay for the diagnosis of scrub typhus, using the indirect immunoperoxidase (IIP) test as the reference standard. The dipstick assays were the Integrated Diagnostics (Baltimore, MD) Dip-S-Ticks Scrub Recombinant (r56) dipstick test (INDX assay) and the PanBio (Brisbane, Australia) Scrub Typhus IgM and IgG Rapid Immunochromatographic test (PanBio assay). One of the ELISAs used pooled cell lysates of Karp, Kato, and Gilliam strain Orientia tsutsugamushi as antigen (pooled-antigen ELISA), and the other used a recombinant r56 protein as the antigen (recombinant ELISA). With a panel of 123 positive and 227 negative sera, sensitivity and specificity of the assays were as follows: INDX assay, IgG, 60% and 95%, IgM, 60% and 97%; PanBio assay, IgG, 94% and 96%, IgM, 83% and 93%; IFA (1:400 cutoff), IgG, 91% and 96%, IgM, 85% and 98%; pooled-antigen ELISA, IgG (1:1600 cutoff), 97% and 89%, IgM (1:400 cutoff), 94% and 91%; recombinant ELISA, IgG (1:1600 cutoff), 97% and 92%, IgM (1:400 cutoff), 93% and 94%. Because of its excellent performance and use of a standardized, commercially available antigen, the recombinant ELISA is suitable for use in a diagnostic laboratory, where it may be able to replace the IFA and IIP assays. In contrast, the PanBio dipstick assay was easy to perform and did not require sophisticated equipment, making it suitable for use in rural areas where more sophisticated diagnostic tests such as the ELISA and IFA may not be available.

Save