Department of Gynecology/Obstetrics, Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Yaoundé, Cameroon.
Gynecology and Obstetrics Unit, Central Hospital of Yaoundé, Yaoundé, Cameroon.
Malar J. 2022 Mar 9;21(1):78. doi: 10.1186/s12936-022-04109-6.
The need to start treatment early for pregnant women who present with clinical features of malaria usually conflicts with the need to confirm diagnosis by microscopy (MP) before treatment, due to delays in obtaining results. Parasite sequestration in the placenta is also a problem. Rapid diagnostic tests (RDT), which detect soluble antigens, are a valuable alternative. The objective of this study was to evaluate pretreatment parasite prevalence by microscopy and by RDT and to assess the accuracy of RDT with MP as reference.
A prospective cross-sectional study was carried out at the obstetrical unit of the Central Hospital in Yaoundé, during the period January-August 2015. Consenting patients with symptoms of suspected malaria in pregnancy were recruited and a blood sample taken for MP and RDT before treatment was started. The estimates of diagnostic performance (with 95% confidence interval) were calculated in OpenEpi online software using the Wilson's score. The agreement, as reflected by the Cohen's kappa, was calculated and interpreted using known intervals.
The results showed that, out of the 104 patients recruited, 69.2% (95%CI: 59.1-77.5) were MP positive while 77.94% (95%CI: 63.1-80.9) were RDT positive. The sensitivity of the malaria RDT was 91.67% (95%CI: 83.69-96.77) while the specificity was 53.13% (95%CI: 31.39-65.57). The diagnostic accuracy of the RDT with MP as reference was 79.81% (95%CI: 70.0-86.1). All cases were due to Plasmodium falciparum. A Cohen's kappa of 0.45 (95%CI: 0.26-0.64) was obtained, consistent with a moderate agreement between the tests.
The diagnostic accuracy of the CareStart™ malaria Pf/PAN compared to microscopy was high, but not as desirable, with a false negative RDT at very high parasitaemia. In tertiary facilities, RDTs appear to provide a better diagnostic solution compared to microscopy. However, future studies with larger sample sizes should make this observation more generalizable; as missing a case could have serious consequences on pregnancy outcome.
对于出现疟疾临床症状的孕妇，通常需要尽早开始治疗，但由于检测结果耗时较长，因此需要通过显微镜检查（MP）确认诊断。胎盘内寄生虫的寄生也是一个问题。快速诊断检测（RDT）可检测可溶性抗原，是一种有价值的替代方法。本研究的目的是评估 MP 预处理寄生虫流行率和 RDT，并评估 RDT 与 MP 作为参考标准的准确性。
2015 年 1 月至 8 月期间，在雅温得中央医院产科进行了一项前瞻性横断面研究。招募有疑似疟疾妊娠症状且同意的患者，并在开始治疗前采集血样进行 MP 和 RDT。在 OpenEpi 在线软件中使用 Wilson 评分计算诊断性能（95%置信区间）的估计值。使用已知区间计算并解释一致性，反映为 Cohen's kappa。
结果显示，在招募的 104 名患者中，69.2%（95%CI：59.1-77.5）为 MP 阳性，77.94%（95%CI：63.1-80.9）为 RDT 阳性。疟疾 RDT 的敏感性为 91.67%（95%CI：83.69-96.77），特异性为 53.13%（95%CI：31.39-65.57）。以 MP 为参考的 RDT 诊断准确性为 79.81%（95%CI：70.0-86.1）。所有病例均由恶性疟原虫引起。获得了 Cohen's kappa 值为 0.45（95%CI：0.26-0.64），表明两种检测方法之间存在中度一致性。
与显微镜相比，CareStart™ 疟疾 Pf/PAN 的诊断准确性较高，但在高寄生虫血症时，RDT 出现假阴性，结果并不理想。在三级医疗机构中，RDT 似乎比显微镜提供了更好的诊断解决方案。然而，未来应进行更大样本量的研究，使这一观察结果更具普遍性；因为漏诊可能会对妊娠结局产生严重后果。
