Table 2.

Summary of diagnostic accuracy studies

Country	Type of test	Source of assay	Total cases	Antigenic strain	Positivity cutoff titer	Antibody target	Positivity criteria	Cutoff justification	Reference
Israel	IFA	NA	23	NA	≥ 1:100	Whole	Single titer	NA	74
Lao PDR	IFA	Australian Rickettsial Reference Laboratory, Victoria, Australia	1030	Wilmington	≥ 1:400	IgM	Single titer	17	75
					≥ 4-fold increase	IgM and IgG	Only 4-fold
	IFA	NA	50	Wilmington	≥ 1:400	Whole	Both	17	76
					≥ 4-fold increase	Whole
Peru, United States, Somalia, and Indonesia	IFA	NA	60	Wilmington	≥ 1:128	IgG	Single titer	NA	8
Russia, Peru, and Burundi	IFA	Dynatech Laboratories Ltd, UK	308	Wilmington	≥ 1:128	IgG	Single titer	25,26	13

IFA = immunofluorescence assay.