Buhalata Simon N, Massaga Julius J
National Institute for Medical Research, Mwanza Medical Research Centre, PO. Box 1462, Mwanza, Tanzania.
National Institute for Medical Research, PO. Box 9653, Dar es Salaam, Tanzania.
Tanzan J Health Res. 2011 Jan;13(1):48-53. doi: 10.4314/thrb.v13i1.60681.
Malaria rapid diagnostic tests (RDTs) are non microscopic tests that provide a rapid detection of malaria infections in infected individuals. The objective of this study was to evaluate the performance of ParaHit and OptiMAL tests for detection of malaria infections as compared with routine microscopy. This facility-based study was carried out in Mwanza, north-western Tanzania and involved outpatients attending Igoma Health Centre. Blood samples were tested for malaria infection using the two RDTs and compared with Giemsa stained blood films examined using microscope. A total of 243 individuals (median age= 22 years) were involved in the study. Microscopy had a higher detection rate of 19.7% (48/243) as compared to ParaHit (4.5%) and OptiMAL (3.7%). Low sensitivity of 21.2% and 17%, but high specificity of 99.4% for ParaHit and OptiMAL, respectively was observed. Of all positive blood slides for Plasmodium falciparum, 78.7% had low parasite density (80 -720 parasite/microl of blood). These slides were negative for malaria parasite for both RDTs. Over 80% of study participants who reported fever had negative blood slides for malaria parasites by microscopy. On the other hand, 44.7% of those who reported no fever had positive blood slides for P. falciparum. Study participants who reported to have fever and high parasite density above 720 parasite/ microl were likely to be positive by both RDTs (OR= 6.8; P= 0.031529). In conclusion, the overall performance of both RDTs in detecting asexual P. falciparum was low as compared to microscopy and their performance were highly affected by parasite density. This calls for further evaluation studies before RDTs are widely used in peripheral health facilities in order to minimize potential severe consequences.
疟疾快速诊断检测（RDTs）是一种非显微镜检测方法，可快速检测出受感染个体是否感染疟疾。本研究的目的是评估与常规显微镜检查相比，ParaHit和OptiMAL检测在检测疟疾感染方面的性能。这项基于机构的研究在坦桑尼亚西北部的姆万扎进行，涉及到伊戈马健康中心的门诊患者。使用这两种RDTs对血样进行疟疾感染检测，并与用显微镜检查的吉姆萨染色血涂片进行比较。共有243人（中位年龄 = 22岁）参与了该研究。与ParaHit（4.5%）和OptiMAL（3.7%）相比，显微镜检查的检测率更高，为19.7%（48/243）。观察到ParaHit和OptiMAL的敏感性分别较低，为21.2%和17%，但特异性较高，分别为99.4%。在所有恶性疟原虫阳性血涂片样本中，78.7%的样本寄生虫密度较低（每微升血液中有80 - 720个寄生虫）。这两种RDTs对这些样本的疟疾寄生虫检测结果均为阴性。超过80%报告有发热症状的研究参与者，其疟疾寄生虫血涂片经显微镜检查为阴性。另一方面，44.7%报告无发热症状的参与者，其恶性疟原虫血涂片呈阳性。报告有发热症状且寄生虫密度高于每微升720个寄生虫的研究参与者，两种RDTs检测结果更有可能呈阳性（比值比 = 6.8；P = 0.031529）。总之，与显微镜检查相比，这两种RDTs在检测无性疟原虫方面的总体性能较低，且其性能受寄生虫密度的影响很大。这就要求在RDTs广泛应用于基层医疗机构之前进行进一步的评估研究，以尽量减少潜在的严重后果。
