Table 2.

Serological and travel history characteristics of serum samples used for Euroimmun IgM ELISA kit evaluation at the NML (N = 247)

	CHIKV IgM+*	CHIKV IgM−†
Number of samples tested	100	147
Serology
Confirmed by PRNT only	54	0
Confirmed by real-time RT-PCR only	10	0
Confirmed by HAI only	13	0
Confirmed by both PRNT and HAI	17	0
Confirmed by both real-time RT-PCR and HAI	3	0
Confirmed by both PRNT and real-time RT-PCR	2	0
Confirmed by PRNT, real-time RT-PCR, and HAI	1	0
Travel history
Travel to Americas‡	63	31
Travel to Asia	2	4
Travel to Africa	2	1
Travel to Oceania	2	0
No travel history provided	31	111

CHIKV = chikungunya virus; ELISA = enzyme-linked immunosorbent assay; HAI = hemagglutination inhibition assay; PRNT = plaque reduction neutralization assay; NML = the Public Health Agency of Canada National Microbiology Laboratory; RT-PCR = reverse transcription polymerase chain reaction.

^*Serum samples were classified as originating from confirmed cases of CHIKV infection if CHIK IgM+ and either PRNT and/or real-time RT-PCR and/or HAI positive. Samples were identified as either CHIKV IgM+ or IgM− using an in-house CDC-based IgM ELISA.

^†See Table 3 for description of sample panel with no detectable CHIK IgM antibodies.

^‡South America, Central America, or the Caribbean; two CHIKV IgM samples with travel history to Mexico were also included.