Institut de Recherche en Science de la Santé-Unité de Recherche Clinique de Nanoro, Nanoro, Burkina Faso.
Amsterdam University Medical Centers, Academic Medical Centre, University of Amsterdam, Department of Medical Microbiology, Parasitology Unit, Amsterdam, The Netherlands.
PLoS One. 2019 Feb 13;14(2):e0211801. doi: 10.1371/journal.pone.0211801. eCollection 2019.
Malaria rapid diagnostic tests (RDT) have limitations due to the persistence of histidine-rich protein 2 (HRP2) antigen after treatment and low sensitivity of Plasmodium lactate dehydrogenase (pLDH) based RDTs. To improve the diagnosis of malaria in febrile children, two diagnostic algorithms, based on sequential interpretation of a malaria rapid diagnostic test detecting two different targets of Plasmodium species and followed by expert microscopy, were evaluated.
Two diagnostic algorithms were evaluated using 407 blood samples collected between April and October 2016 from febrile children and the diagnostic accuracy of both algorithms was determined. Algorithm 1: The result of line T1-HRP2 were read first; if negative, malaria infection was considered to be absent. If positive, confirmation was done with the line T2-pLDH. If T2-pLDH test was negative, the malaria diagnosis was considered as "inconclusive" and microscopy was performed; Algorithm 2: The result of line T2-pLDH were read first; if positive, malaria infection was considered to be present. If negative, confirmation was done with the line T1-HRP2. If T1-HRP2 was positive the malaria diagnosis was considered as "inconclusive" and microscopy was performed. In absence of malaria microscopy, a malaria infection was ruled out in children with an inconclusive diagnostic test result when previous antimalarial treatment was reported.
For single interpretation, the sensitivity of PfHRP2 was 98.4% and the specificity was 74.2%, and for the pLDH test the sensitivity was 89.3% and the specificity was 98.8%. Malaria was accurately diagnosed using both algorithms in 84.5% children. The algorithms with the two-line malaria RDT classified the test results into two groups: conclusive and inconclusive results. The diagnostic accuracy for conclusive results was 98.3% using diagnostic algorithm 1 and 98.6% using algorithm 2. The sensitivity and specificity for the conclusive results were 98.2% and 98.4% for algorithm 1, and 98.6% and 98.4% for algorithm 2, respectively. There were 63 (15.5%) children who had an "inconclusive" result for whom expert microscopy was needed. In children with inconclusive results (PfHRP2+/pLDH- only) previous antimalarial treatment was reported in 16 children with malaria negative microscopy (16/40; 40%) and 1 child with malaria positive microscopy (1/23; 4.3%).
The strategy of sequential interpretation of two-line malaria RDT can improve the diagnosis of malaria. However, some cases will still require confirmative testing with microscopy or additional investigations on previous antimalarial treatment.
由于治疗后组织蛋白酶 B（HRP2）抗原持续存在以及基于疟原乳酸脱氢酶（pLDH）的 RDT 敏感性低，疟疾快速诊断检测（RDT）存在局限性。为了提高发热儿童疟疾的诊断准确性，评估了两种基于疟原虫两种不同靶标检测的疟疾快速诊断检测的顺序解释，然后结合专家镜检的两种诊断算法。
2016 年 4 月至 10 月期间，从发热儿童中采集了 407 份血液样本，使用两种诊断算法进行评估，并确定了两种算法的诊断准确性。算法 1：首先读取线 T1-HRP2 的结果；如果为阴性，则认为不存在疟疾感染。如果为阳性，则用线 T2-pLDH 进行确认。如果 T2-pLDH 检测为阴性，则将疟疾诊断视为“不确定”，并进行显微镜检查；算法 2：首先读取线 T2-pLDH 的结果；如果为阳性，则认为存在疟疾感染。如果为阴性，则用线 T1-HRP2 进行确认。如果 T1-HRP2 为阳性，则将疟疾诊断视为“不确定”，并进行显微镜检查。如果没有疟疾显微镜检查，当报告有先前的抗疟治疗时，对于不确定诊断检测结果的儿童，排除疟疾感染。
对于单一解释，PfHRP2 的灵敏度为 98.4%，特异性为 74.2%，而 pLDH 检测的灵敏度为 89.3%，特异性为 98.8%。使用两种算法在 84.5%的儿童中准确诊断了疟疾。使用两线疟疾 RDT 的算法将检测结果分为两组：确定和不确定结果。使用诊断算法 1 时，确定结果的诊断准确性为 98.3%，使用算法 2 时为 98.6%。对于确定结果，算法 1 的灵敏度和特异性分别为 98.2%和 98.4%，算法 2 的灵敏度和特异性分别为 98.6%和 98.4%。有 63 名（15.5%）儿童的检测结果为“不确定”，需要进行专家显微镜检查。在不确定结果的儿童中（仅 PfHRP2+/pLDH-），有 16 名疟疾阴性显微镜检查的儿童（16/40；40%）和 1 名疟疾阳性显微镜检查的儿童（1/23；4.3%）报告了先前有抗疟治疗。
两线疟疾 RDT 顺序解释策略可以提高疟疾的诊断准确性。然而，仍有一些病例需要通过显微镜检查或对先前抗疟治疗进行额外调查来确认。
