4.4.3 Is there need to apply confirmatory tests?

In general, the sensitivity [1] and specificity [2] of the FAT and DRIT are very high, but may be influenced by the quality of the specimen, conjugate, equipment and the skills and experience of the people involved in rabies diagnosis. Under certain limited circumstances, failure to detect viral antigens in brain tissue does not rule out an infection. In general, there is no need to confirm truly FAT- or DRIT-negative results by alternative tests in animal surveillance. However, in case of FAT- or DRIT-negative results on samples associated with a known history of human exposure, or in case of FAT-or DRIT inconclusive results such confirmatory tests may be applied (see section 4.4.5).
Truly inconclusive tests should be treated as positives as long as confirmatory tests attest or rule out infection and post-exposure prophylaxis is provided according to WHO recommendations.

[1sensitivity is the proportion of truly positive units that are correctly identified as positive by a test. It is a measure of the confidence in the ability of the surveillance applied to detect infection.

[2specificity is the the proportion of truly negative units that are correctly identified as negative by a test.

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[en]Version 1 Last updated December 2014[fr]Première version, dernière mise à jour Juin 2015