title: Comparative evaluation of four techniques for the diagnosis of Plasmodium falciparum infections.
abstract: Four diagnostic techniques for Plasmodium falciparum infection were evaluated against serial parasite dilutions and on identical field samples. These were (i) Giemsa-stained thick blood films (GTF), (ii) acridine orange-stained thick (AOTF) and thin (AOTnF) blood films, (iii) the quantitative buffy coat technique (QBC); and (iv) the ParaSight-F dipstick test (PS). PS had a consistently higher sensitivity and speed, was easiest to learn, and required no laboratory facility. The 100% sensitivity cut-off points against known parasite densities (per mm3) were: PS, 30; GTF, 84; QBC, 84; AOTnF, 84; AOTF, 149. In the field study, test sensitivities compared with examination of 800 microscope fields of a Giemsa-stained thin blood film were PS, 96.6%; AOTF, 93.1%; GTF, 91.4%; QBC, 89.7%; AOTnF, 82.8%. In the dilution study, one false positive result was recorded with QBC; in the field study there was one false positive each with PS, AOTnF and AOTF. When a newly trained microscopist examined samples of the parasite dilutions, the 100% sensitivity cut-off points were AOTF, 84; GTF, 140; QBC, 390. Total handling time was shortest with PS regardless of whether samples were processed individually or in batches of 10 or 100. The ParaSight-F test is recommended as the diagnostic tool for the future.
authors.affiliation: South African Medical Research Council, Durban, South Africa.
authors.forename: M H
authors.initials: MH
authors.lastname: Craig
authors.forename: B L
authors.initials: BL
authors.lastname: Sharp
mesh_terms: D004797:Enzyme-Linked Immunosorbent Assay; D005069:Evaluation Studies as Topic; D006801:Humans; D016778:Malaria, Falciparum / Q000175:diagnosis*; D008856:Microscopy, Fluorescence; D010274:Parasitology / Q000379:methods*; D011934:Reagent Strips; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D011934:Reagent Strips