Measurement of Circulating Filarial Antigen Levels in Human Blood with a Point-of-Care Test Strip and a Portable Spectrodensitometer.
The Alere Filariasis Test Strip (FTS) is a qualitative, point-of-care diagnostic tool that detects Wuchereria bancrofti circulating filarial antigen (CFA) in human blood, serum, or plasma. The Global Program to Eliminate Lymphatic Filariasis employs the FTS for mapping filariasis-endemic areas and assessing the success of elimination efforts. The objective of this study was to explore the relationship between the intensity of positive test lines obtained by FTS with CFA levels as determined by enzyme-linked immunosorbent assay (ELISA) with blood and plasma samples from 188 individuals who live in a filariasis-endemic area. The intensity of the FTS test line was assessed visually to provide a semiquantitative score (visual Filariasis Test Strip [vFTS]), and line intensity was measured with a portable spectrodensitometer (quantitative Filariasis Test Strip [qFTS]). These results were compared with antigen levels measured by ELISA in plasma from the same subjects. qFTS measurements were highly correlated with vFTS scores (ρ = 0.94; P < 0.001) and with plasma CFA levels (ρ = 0.91; P < 0.001). Thus, qFTS assessment is a convenient method for quantifying W. bancrofti CFA levels in human blood, which are correlated with adult worm burdens. This tool may be useful for assessing the impact of treatment on adult filarial worms in individuals and communities.
Cédric B
CB
Chesnais
Johnny
J
Vlaminck
Billy
B
Kunyu-Shako
Sébastien D
SD
Pion
Naomi-Pitchouna
NP
Awaca-Uvon
Gary J
GJ
Weil
Dieudonné
D
Mumba
Michel
M
Boussinesq
D000818:Animals; D000947:Antigens, Helminth / Q000097:blood*; D004605:Elephantiasis, Filarial / Q000175:diagnosis*; D006801:Humans; D000067716:Point-of-Care Testing; D011934:Reagent Strips; D012680:Sensitivity and Specificity; D014958:Wuchereria bancrofti / Q000276:immunology* / Q000378:metabolism
D000947:Antigens, Helminth; D011934:Reagent Strips