The ParaSight®-F rapid dipstick antigen capture assay for monitoring parasite clearance after drug treatment of Plasmodium falciparum malaria

Three methods for the detection of Plasmodium falciparum infection in peripheral blood were compared during antimalarial treatment and follow-up in 32 Burundian patients: dipstick antigen capture assay, standard (TBF) and prolonged thick blood film examination (PTBF) (3 x 5 min and 3 x 20 min examination respectively). Parasitaemia was determined daily by comparison with total white blood cell counts (determined by Coulter counter) until no parasite was detected on 2 consecutive days by PTBF. Cumulatively, 231 observations were made with each assay: 64 were negative and 167 positive by PTBF (59 had parasite counts ≤ 100/μL). Compared to PTBF, the sensitivities of TBF and the dipstick assay were 1.0 for parasite counts > 100/μL and 0.458 and 0.966 respectively for counts ≤ 100/μL. Overall, the dipstick assay was significantly more sensitive (0.988 vs. 0.808; P < 0.001) but less specific (P = 0.013) than TBF. The dipstick assay is of potential use for monitoring response to drug treatment and for detecting low parasitaemias.