Malaria Consortium, Upper Naguru East Road, P,O, Box 8045, Kampala, Uganda.
Malar J. 2011 Oct 18;10:306. doi: 10.1186/1475-2875-10-306.
Malaria has a negative effect on the outcome of pregnancy. Pregnant women are at high risk of severe malaria and severe haemolytic anaemia, which contribute 60-70% of foetal and perinatal losses. Peripheral blood smear microscopy under-estimates sequestered placental infections, therefore malaria rapid diagnostic tests (RDTs) detecting histidine rich protein-2 antigen (HRP-2) in peripheral blood are a potential alternative.
HRP-2 RDTs accuracy in detecting malaria in pregnancy (MIP >28 weeks gestation) and placental Plasmodium falciparum malaria (after childbirth) were conducted using Giemsa microscopy and placental histopathology respectively as the reference standard. The study was conducted in Mbale Hospital, using the midwives to perform and interpret the RDT results. Discordant results samples were spot checked using PCR techniques.
Among 433 febrile women tested, RDTs had a sensitivity of 96.8% (95% CI 92-98.8), specificity of 73.5% (95% CI 67.8-78.6), a positive predictive value (PPV) of 68.0% (95% CI 61.4-73.9), and negative predictive value (NPV) of 97.5% (95% CI 94.0-99.0) in detecting peripheral P. falciparum malaria during pregnancy. At delivery, in non-symptomatic women, RDTs had a 80.9% sensitivity (95% CI 57.4-93.7) and a 87.5% specificity (95%CI 80.9-92.1), PPV of 47.2% (95% CI 30.7-64.2) and NPV of 97.1% (95% CI 92.2-99.1) in detecting placental P. falciparum infections among 173 samples. At delivery, 41% of peripheral infections were detected by microscopy without concurrent placental infection. The combination of RDTs and microscopy improved the sensitivity to 90.5% and the specificity to 98.4% for detecting placental malaria infection (McNemar's X(2)> 3.84). RDTs were not superior to microscopy in detecting placental infection (McNemar's X(2)< 3.84). Presence of malaria in pregnancy and active placental malaria infection were 38% and 12% respectively. Placental infections were associated with poor pregnancy outcome [pre-term, still birth and low birth weight] (aOR = 37.9) and late pregnancy malaria infection (aOR = 20.9). Mosquito net use (aOR 2.1) and increasing parity (aOR 2.7) were associated with lower risk for malaria in pregnancy.
Use of HRP-2 RDTs to detect malaria in pregnancy in symptomatic women was accurate when performed by midwives. A combination of RDTs and microscopy provided the best means of detecting placental malaria. RDTs were not superior to microscopy in detecting placental infection. With a high sensitivity and specificity, RDTs could be a useful tool for assessing malaria in pregnancy, with further (cost-) effectiveness studies.
疟疾对妊娠结局有负面影响。孕妇患严重疟疾和严重溶血性贫血的风险很高，这导致 60-70%的胎儿和围产期损失。外周血涂片显微镜检查低估了胎盘感染，因此检测组氨酸丰富蛋白-2 抗原（HRP-2）的疟疾快速诊断检测（RDT）是一种潜在的替代方法。
使用吉姆萨显微镜和胎盘组织病理学分别作为参考标准，对妊娠（妊娠 28 周以上）和胎盘疟原虫疟疾（分娩后）中 HRP-2 RDT 检测疟疾的准确性进行了研究。该研究在姆巴莱医院进行，由助产士进行并解释 RDT 结果。对有分歧的样本进行了点检查，使用了 PCR 技术。
在 433 名发热的妇女中，RDTs 在检测妊娠外周性疟原虫（95%CI 92-98.8）中的敏感性为 96.8%，特异性为 73.5%（95%CI 67.8-78.6），阳性预测值（PPV）为 68.0%（95%CI 61.4-73.9），阴性预测值（NPV）为 97.5%（95%CI 94.0-99.0）。在分娩时，在无症状妇女中，RDTs 的敏感性为 80.9%（95%CI 57.4-93.7），特异性为 87.5%（95%CI 80.9-92.1），PPV 为 47.2%（95%CI 30.7-64.2），NPV 为 97.1%（95%CI 92.2-99.1）。在 173 份样本中，RDTs 检测胎盘疟原虫感染的敏感性为 41%，而无同时发生的胎盘感染。RDTs 和显微镜检查的结合提高了对胎盘疟疾感染的敏感性，达到 90.5%，特异性为 98.4%（McNemar's X(2)> 3.84）。RDTs 在检测胎盘感染方面并不优于显微镜检查（McNemar's X(2)< 3.84）。妊娠疟疾和活动性胎盘疟疾感染分别为 38%和 12%。胎盘感染与不良妊娠结局[早产、死产和低出生体重]（aOR = 37.9）和晚期妊娠疟疾感染（aOR = 20.9）有关。使用蚊帐（aOR 2.1）和增加产次（aOR 2.7）与妊娠疟疾风险降低有关。
在有症状的孕妇中，由助产士进行 HRP-2 RDT 检测妊娠疟疾的结果是准确的。RDTs 和显微镜检查的结合是检测胎盘疟疾的最佳方法。RDTs 在检测胎盘感染方面并不优于显微镜检查。RDTs 具有较高的敏感性和特异性，可作为评估妊娠疟疾的有用工具，进一步进行（成本）效益研究。
