Case report: Initial positive measles IgM tests in two Samoan children were false positivesWhen a measles test says yes, could it really mean no?

An outbreak report from American Samoa describes two pediatric cases of rash illness with initial positive measles IgM test results. The specific intervention or exposure was not reported. The population consisted of two children, though the exact ages and clinical details were not provided. The setting was an outbreak investigation in American Samoa, but the comparator group and primary outcome measures were not specified.

Both children initially tested positive for measles IgM. However, subsequent investigation determined the final confirmed etiology was alternative viral infections, not measles. The report states that 2 children had initial positive tests, and 2 children were ultimately found to have alternative viral etiologies. No effect sizes, p-values, or confidence intervals were reported for these findings.

Safety and tolerability data were not reported. The report did not mention adverse events, serious adverse events, or treatment discontinuations. Key limitations include the very small sample size of only 2 cases, the observational case report design, and multiple unreported details including study phase, follow-up duration, and funding sources. The practice relevance is limited but suggests clinicians should interpret positive measles IgM tests cautiously during rash illness outbreaks, as they may represent false positives when alternative viral etiologies are circulating.