Comparison of Immunochromatographic Test (ICT) and Filariasis Test Strip (FTS) for Detecting Lymphatic Filariasis Antigen in American Samoa, 2016

Circulating filarial antigen (Ag) prevalence, measured using rapid point-of-care tests, is the standard indicator used for monitoring and surveillance in Global Program to Eliminate Lymphatic Filariasis. In 2015, immunochromatographic test (ICT) was replaced with filariasis strip (FTS), which has higher reported sensitivity. Despite differences sensitivity, no changes recommended targets were made when FTS introduced. 2016, we conducted lymphatic surveys American Samoa FTS, found Ag prevalence than previous that ICT. To determine whether increase real, assessed concordance between ICT results by paired testing of heparinised blood from 179 individuals (63% FTS-positive). had 93.8% sensitivity 100% specificity identifying FTS-positive persons, not associated age, gender, or presence microfilariae. Based on these findings, if been 2016 surveys, interpretation would have similar those FTS. failed Transmission Assessment Survey (TAS) Grade 1 2 children either test, community significantly different (4.1%, 95% CI, 3.3–4.9% vs. predicted 3.8%, 95%, CI: 3.1–4.6% ICT).