[ParaSight F in the diagnosis of Plasmodium falciparum malaria]. / Apport du ParaSight F dans le diagnostic du paludisme à Plasmodium falciparum.

ABSTRACT

The ParaSight F is a new diagnostic test for Plasmodium falciparum infections and is based on the detection of a trophozoite-derived antigen, the histidine rich protein II (HRP-II). To assess the usefulness of this test, we conducted a prospective study and analyzed 62 blood specimens from 38 patients, using thin blood films, thick blood films and the ParaSight F test. Compared to thick blood film, on samples taken before and during treatment, the ParaSight F test had 86.4% sensitivity and 100% specificity. In 31.5% of P. falciparum infected patients, parasitemia was lower than 1 parasite/1000 red blood cells, with all specimens being positive by the ParaSight F test. In 15 cases, specimens were negative by thin blood film, but were positive by thick blood film and by the ParaSight F test. Two patients had, after their treatment was started, positive results by ParaSight F and negative results by thick blood film. Cross-reactivity occurred neither with other Plasmodium species, nor in cases of severe inflammatory syndrome. Persistence of antigenemia was monitored in 14 patients receiving quinine. At day five of treatment, antigenemia persisted in seven patients. In conclusion, the ParaSight F test does not allow following up the efficacy of treatment, identifying other Plasmodium species, or assessing parasitemia. However, because this test is easy to perform and has good sensitivity and specificity, it is a useful tool in emergent context, in cases of parasitemia lower than the thin blood film threshold, and in cases morphologically difficult to decipher.