Evaluation of the rapid diagnostic test OptiMAL for diagnosis of malaria due to Plasmodium vivax

Abstract

OBJECTIVE: To determine the sensitivity and specificity of the rapid diagnostic test OptiMAL® for diagnosis of Plasmodium vivax malaria. MATERIAL AND METHODS: We included all the patients who sought medical attention in the San Martin Pangoa Hospital, Junin, an area endemic for vivax malaria in Peru, between October and December 1998, who had fever during the previous 72 hours and who were older than 12 months. The gold standard for diagnosis was thick blood film microscopy. We determined the parasitemia rate for each of the positive slides. We calculated sensitivity, specificity, positive predictive value and negative predictive value of the test. RESULTS: We included 72 patients; 39 of them were positive for P. vivax by microscopic examination. The sensitivity of the Optimal test was 92.3%, the specificity 100%, the positive predictive value 100% and the negative predictive value 91.6%. The accuracy of the test was 95.8%. The sensitivity of the OptiMAL® test progressively decreased when parasitemia was lower than 1,000 parasites/microliter. CONCLUSIONS: the OptiMAL® test has a high sensitivity and specificity for diagnosis of P. vivax malaria. However, its sensitivity decreased when parasitemia levels were lower. It is a very simple technique, which makes it a good alternative for malaria diagnosis in remote places, although its elevated cost is still a problem

Field evaluation of a rapid diagnostic test (Parascreen™) for malaria diagnosis in the Peruvian Amazon

“…HRP2-based RDTs such as Parascreen™ have also been evaluated in various studies in South American countries [25-28]. The sensitivity and specificity for P. falciparum and P. vivax infections observed in this study were better than those reported with AMRAD fast test ICT P.f/P v in Peru [6], and similar to those obtained with Binax NOW™ fast test ICT P.f/P.v in Colombia, but lower than those observed with NOW-Malaria-ICT RDT in an evaluation study in Colombia [18] and in various other studies of OptiMAL IT [6,10,11,13,26]. …”

Evaluation of Three Rapid Tests for Diagnosis of P. Falciparum and P. Vivax Malaria in Colombia

“…Optimal was evaluated positively by most researchers but not all: in Latin America, sensitivities for P. falciparum averaged 82% (range 42-100%) and for P. vivax 88% (65-100), including studies from Colombia, [15][16][17] Honduras, 4,18 Mexico, 19 Peru, 20 and Brazil; 21 in Asia it showed about 87% (79-94) sensitivity for P. falciparum and 80% (65-95) for P. vivax (Afghanistan, 22 Thailand, 23 Pakistan, 24 Kuwait 8 ). The NOW test and its predecessor ICT Pf/Pv were reported to be very sensitive for P. falciparum, about 96% (range 89-100) and a bit lower but acceptably sensitive for non-P. falciparum infections, about 87% (range 75-100, Colombia [Mendoza and others, unpublished data], Indonesia, 5 Thailand 25,26 ).…”

Malaria rapid diagnostic tests in endemic settings

“…The lower specificity of PfHRP2‐detecting RDTs can partly be explained by the slow clearance of PfHRP2: in patients with recently treated or self‐cleared infections PfHRP2 may persist in the blood for several weeks and still be present during a new episode of fever. For P. vivax diagnosis, reported sensitivities for pan‐pLDH, Pv‐pLDH and aldolase‐detecting RDTs are, respectively, 76.1–100.0% , 76.9–100.0% and 80.0–81.4% . A prospective field study in Peru, comparing side‐to‐side 11 RDT products, revealed high sensitivity (>99.0%) for 9/11 products with no difference between pan‐pLDH vs. Pv‐pLDH detection .…”