Sensitivity of the immunochromatographic card test relative to detection of adult Wuchereria bancrofti worms by ultrasound.

The diagnosis of active infection in bancroftian filariasis continues to pose an important and continuously evolving challenge to filariasis-endemic countries and to health personnel. Sensitivity of the immunochromatographic card test (ICT) relative to detection of adult Wuchereria bancrofti worms by ultrasound was evaluated in a retrospective study conducted in the Center for Teaching, Research and Tertiary Referral Hospital for bancroftian filariasis (Federal University of Pernambuco) in Recife, Brazil. The results showed that among 408 persons tested, the overall sensitivity of the ICT was 84.5% and varied from 52% to 100% when patients were grouped by different criteria (age, sex, presence or absence of living adult worms by ultrasound, microfilaremia status/density). The present study provides evidence that a negative antigen result should be interpreted cautiously and may help to explain the different sensitivities of the antigen test found by different investigators in settings with different transmission intensities.