Evaluation of the Rapid Diagnostic Test OptiMAL for Diagnosis of Malaria due to

Cayetano Heredia University, Institute of Tropical Medecine Alexander von Humboldt, Lima, Peru.
Brazilian Journal of Infectious Diseases (Impact Factor: 1.3). 05/2004; 8(2):151-5. DOI: 10.1590/S1413-86702004000200005
Source: PubMed


To determine the sensitivity and specificity of the rapid diagnostic test OptiMAL for diagnosis of Plasmodium vivax malaria.
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.
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.
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.

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Available from: Daniel Mendoza, Apr 30, 2015
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    • "False-positive reactions of P. vivax samples with the HRP-2 line and the Pf-pLDH line have been described previously [24-26], but the presently observed false-positive Pv-pLDH lines in P. falciparum samples have only been reported anecdotally [2-4,22]. Among the panel of RDTs tested in the WHO and Foundation for Innovative New Diagnostics (FIND) study, there were two RDTs with a Pv-pLDH line: according to the tables, one of them generated false positive Pv-pLDH lines in 1.9% (6/316) of the P. falciparum samples tested. "
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    ABSTRACT: Most malaria rapid diagnostic tests (RDTs) detect Plasmodium falciparum and an antigen common to the four species. Plasmodium vivax-specific RDTs target P. vivax-specific parasite lactate dehydrogenase (Pv-pLDH). Previous observations of false positive Pv-pLDH test lines in P. falciparum samples incited to the present study, which assessed P. vivax-specific RDTs for the occurrence of false positive Pv-pLDH lines in P. falciparum samples. Nine P. vivax-specific RDTs were tested with 85 P. falciparum samples of high (>or=2%) parasite density. Mixed P. falciparum/P. vivax infections were ruled out by real-time PCR. The RDTs included two-band (detecting Pv-pLDH), three-band (detecting P. falciparum-antigen and Pv-pLDH) and four-band RDTs (detecting P. falciparum, Pv-pLDH and pan-pLDH). False positive Pv-pLDH lines were observed in 6/9 RDTs (including two- three- and four-band RDTs). They occurred in the individual RDT brands at frequencies ranging from 8.2% to 29.1%. For 19/85 samples, at least two RDT brands generated a false positive Pv-pLDH line. Sixteen of 85 (18.8%) false positive lines were of medium or strong line intensity. There was no significant relation between false positive results and parasite density or geographic origin of the samples. False positive Pv-pLDH lines in P. falciparum samples with high parasite density occurred in 6/9 P. vivax-specific RDTs. This is of concern as P. falciparum and P. vivax are co-circulating in many regions. The diagnosis of life-threatening P. falciparum malaria may be missed (two-band Pv-pLDH RDT), or the patient may be treated incorrectly with primaquine (three- or four-band RDTs).
    Full-text · Article · Jul 2010 · Malaria Journal
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    • "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]. "
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    ABSTRACT: The rapid diagnostic tests for malaria (RDT) constitute a fast and opportune alternative for non-complicated malaria diagnosis in areas where microscopy is not available. The objective of this study was to validate a RDT named Parascreen under field conditions in Iquitos, department of Loreto, Peru. Parascreen is a RDT that detects the histidine-rich protein 2 (HRP2) antigen from Plasmodium falciparum and lactate deshydrogenase from all Plasmodium species. Parascreen was compared with microscopy performed by experts (EM) and polymerase chain reaction (PCR) using the following indicators: sensitivity (Se), specificity (Sp), positive (PV+) and negative predictive values (PV-), positive (LR+) and negative likehood ratio (LR-). 332 patients with suspected non-complicated malaria who attended to the MOH health centres were enrolled between October and December 2006. For P. falciparum malaria, Parascreen in comparison with EM, had Se: 53.5%, Sp: 98.7%, PV+: 66.7%, PV-: 97.8%, LR+: 42.27 and LR-: 0.47; and for non-P. falciparum malaria, Se: 77.1%, Sp: 97.6%, PV+: 91.4%, PV-: 92.7%, LR+: 32.0 and LR-: 0.22. The comparison of Parascreen with PCR showed, for P. falciparum malaria, Se: 81.8%, Sp: 99.1%, PV+: 75%, PV-: 99.4, LR+: 87.27 and LR-: 0.18; and for non-P. falciparum malaria Se: 76.1%, Sp: 99.2%, PV+: 97.1%, PV-: 92.0%, LR+: 92.51 and LR-: 0.24. The study results indicate that Parascreen is not a valid and acceptable test for malaria diagnosis under the field conditions found in the Peruvian Amazon. The relative proportion of Plasmodium species, in addition to the genetic characteristics of the parasites in the area, must be considered before applying any RDT, especially after the finding of P. falciparum malaria parasites lacking pfhrp2 gene in this region.
    Full-text · Article · Jun 2010 · Malaria Journal
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    • "Although rapid diagnostic tests for malaria have been extensively field tested in Africa, little research has focused on their effectiveness in Latin America. However , recent trials of a rapid diagnostic test in Mexico and Peru have demonstrated sufficient sensitivity and specificity for diagnosis of P. vivax in rural communities (Gonzalez- Ceron et al., 2005; Soto Tarazona et al., 2004). Whilst microscopy remains the gold standard for malaria diagnosis, rapid tests can provide a quick, cheap and simple alternative in communities without direct access to a primary healthcare facility and their use requires minimal training. "
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    ABSTRACT: Inequitable access to healthcare has a profound impact on the health of marginalised groups that typically suffer an excess burden of infectious disease morbidity and mortality. The Yanomami are traditionally semi-nomadic people living in widely dispersed communities in Amazonian Venezuela and Brazil. Only communities living in the vicinity of a health post have relatively constant access to healthcare. To monitor the improvement in the development of Yanomami healthcare a cross-sectional survey of 183 individuals was conducted to investigate malaria and anaemia prevalence in communities with constant and intermittent access to healthcare. Demographic and clinical data were collected. Malaria was diagnosed by microscopy and haemoglobin concentration by HemoCue. Prevalence of malaria, anaemia, splenomegaly, fever and diarrhoea were all significantly higher in communities with intermittent access to healthcare (anaemia 80.8% vs. 53.6%, P<0.001; malaria 18.2% vs. 6.0%, P=0.013; splenomegaly 85.4% vs.12.5%, P<0.001; fever 50.5% vs. 28.6%, P=0.003; diarrhoea 30.3% vs.10.7% P=0.001). Haemoglobin level (10.0 g/dl vs. 11.5 g/dl) was significantly associated with access to healthcare when controlling for age, sex, malaria and splenomegaly (P=0.01). These findings indicate a heavy burden of anaemia in both areas and the need for interventions against anaemia and malaria, along with more frequent medical visits to remote areas.
    Full-text · Article · Aug 2008 · Transactions of the Royal Society of Tropical Medicine and Hygiene
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