Felege Hiwot Referral Specialized Hospital, Medical Laboratory Service, Bahir Dar, Ethiopia.
Department of Medical Laboratory Sciences, School of Health Sciences, College of Medicine and Health Sciences, Bahir Dar University, Bahir Dar, Ethiopia.
PLoS One. 2018 Oct 18;13(10):e0203420. doi: 10.1371/journal.pone.0203420. eCollection 2018.
Microscopic diagnosis of Giemsa stained thick and thin blood films by skilled microscopists has remained the gold standard laboratory method for the diagnosis of malaria. However, there is a scarcity of qualified laboratory professionals for correctly diagnosing malaria using microscopy. The aim of this study was to evaluate the performance of laboratory professionals on malaria microscopy at health facilities in Bahir Dar city administration, Northwest Ethiopia.
A cross-sectional study was conducted from January to March 2017 in Bahir Dar City. A total of 87 laboratory professionals participated in the selected health facilities, with a response rate of (100%). Standardized pre-validated slide panels and questionnaire were distributed to laboratory professionals by the principal investigator. The panel slides were comprised of 5 positives and 3 negative blood films. The laboratory professionals were requested to report the parasite density using semi-quantitative (+) and per micro-liter methods. Their performances of slide readings were compared with the experts' readings. Agreement in detecting malaria parasites between laboratory professionals and expert was estimated using the kappa score.
The overall sensitivity and specificity of the laboratory professionals in detecting malaria parasites were 83% and 97%, respectively. Similarly, positive predictive values of 98.1% and negative predictive values of 77.7% were reported. The percent agreement between laboratory professionals and expert microscopist in the detection of malaria parasites was 88.5% with a Kappa index of 0.78. Percent agreement in species identification and reporting of Pf/Pv mixed infections were 27.2% and 22.4%, respectively. About 62.2% of the laboratory professionals reported parasite density using semi-quantitative method. While none of them reported per micro-liter method.
The current study showed that laboratory professionals had good performance in parasite detection. However, poor performance was seen in both species identification and reporting of Pf/Pv mixed infections.
熟练的显微镜检查人员对吉姆萨染色的厚、薄血膜进行显微镜检查，一直是疟疾诊断的金标准实验室方法。然而，能够正确使用显微镜诊断疟疾的合格实验室专业人员却十分匮乏。本研究旨在评估巴希尔达市（埃塞俄比亚西北部）卫生机构的实验室专业人员在疟疾显微镜检查方面的表现。
2017 年 1 月至 3 月在巴希尔达市进行了一项横断面研究。共有 87 名实验室专业人员参加了在选定的卫生机构进行的研究，应答率为（100%）。由主要研究者向实验室专业人员分发了标准化的预验证载玻片和问卷。载玻片面板由 5 个阳性和 3 个阴性血片组成。实验室专业人员被要求使用半定量（+）和每微升方法报告寄生虫密度。他们的玻片阅读表现与专家的阅读结果进行了比较。使用 Kappa 评分估计实验室专业人员和专家检测疟原虫的一致性。
实验室专业人员检测疟原虫的总体灵敏度和特异性分别为 83%和 97%。同样，报告的阳性预测值为 98.1%，阴性预测值为 77.7%。实验室专业人员与专家显微镜检查师在检测疟原虫方面的百分比一致性为 88.5%，Kappa 指数为 0.78。在鉴定和报告 Pf/Pv 混合感染方面的百分比一致性分别为 27.2%和 22.4%。约 62.2%的实验室专业人员使用半定量方法报告寄生虫密度。而他们中没有人报告每微升的方法。
本研究表明，实验室专业人员在寄生虫检测方面表现良好。然而，在鉴定和报告 Pf/Pv 混合感染方面表现不佳。
