Lassa fever is a viral haemorrhagic fever with few options for diagnosis and treatment; it is also under-researched with knowledge gaps on its epidemiology. A point-of-care bedside test diagnosing Lassa fever, adhering to REASSURED criteria, is not currently available but is urgently needed in west African regions with high Lassa fever burden. We aimed to assess the validity and feasibility of a rapid diagnostic test (RDT) to confirm Lassa fever in people in Nigeria. We estimated the diagnostic performance of the ReLASV Pan-Lassa RDT (Zalgen Labs, Frederick, MD, USA) as a research-use-only test, compared to RT-PCR as a reference standard, in 217 participants at a federal tertiary hospital in Abakaliki, Nigeria. We recruited participants between Feb 17, 2022, and April 17, 2023. The RDT was performed using capillary blood at the patient bedside and using plasma at the laboratory. The performance of the test, based on REASSURED criteria, was assessed for user friendliness, rapidity and robustness, sensitivity, and specificity. Participants were aged between 0 and 85 years, with a median age of 33·0 years (IQR 22·0–44·3), and 24 participants were younger than 18 years. 107 (50%) participants were women and 109 (50%) were men; one participant had missing sex data. Although the specificity of the Pan-Lassa RDT was high (>90%), sensitivity at bedside using capillary blood was estimated as 4% (95% CI 1–14) at 15 min and 10% (3–22) at 25 min, far below the target of 90%. The laboratory-based RDT using plasma showed better sensitivity (46% [32–61] at 15 min and 50% [36–64] at 25 min) but did not reach the target sensitivity. Among the 52 PCR-positive participants with Lassa fever, positive RDT results were associated with lower cycle threshold values (glycoprotein precursor [GPC] gene mean 30·3 [SD 4·3], Large [L] gene mean 32·3 [3·7] GPC gene mean 24·5 [3·9], L gene mean 28·0 [3·6]). Personnel conducting the bedside test procedure reported being hindered by the inconvenient use of full personal protective equipment and long waiting procedures before a result could be read. The Pan-Lassa RDT is not currently recommended as a diagnostic or screening tool for suspected Lassa fever cases. Marked improvement in sensitivity and user friendliness is needed for the RDT to be adopted clinically. There remains an urgent need for better Lassa fever diagnostics to promote safety of in-hospital care and better disease outcomes in low-resource settings. Médecins Sans Frontières.

中文翻译：

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尼日利亚阿巴卡利基拉沙热泛拉沙快速诊断检测有效性和可行性的现场评估：一项前瞻性诊断准确性研究


拉沙热是一种病毒性出血热，诊断和治疗的选择很少；由于流行病学方面的知识差距，对该病的研究也不足。目前尚无符合 REASSURED 标准的诊断拉沙热的床边床边检测，但拉沙热负担较高的西非地区迫切需要这种检测。我们的目的是评估快速诊断测试（RDT）的有效性和可行性，以确认尼日利亚人的拉沙热。我们评估了 ReLASV Pan-Lassa RDT（Zalgen Labs，弗雷德里克，马里兰州，美国）作为仅供研究使用的测试的诊断性能，与作为参考标准的 RT-PCR 相比，在美国一家联邦三级医院的 217 名参与者中进行了评估。尼日利亚阿巴卡利基。我们在 2022 年 2 月 17 日至 2023 年 4 月 17 日期间招募了参与者。RDT 在患者床边使用毛细血管血并在实验室使用血浆进行。根据 REASSURED 标准，对测试的性能进行了用户友好性、快速性和鲁棒性、敏感性和特异性的评估。参与者年龄在0至85岁之间，中位年龄为33·0岁（IQR 22·0–44·3），其中24名参与者年龄小于18岁。 107 名（50%）参与者为女性，109 名（50%）为男性；一名参与者缺少性别数据。尽管 Pan-Lassa RDT 的特异性很高 (>90%)，但床边使用毛细血管血的敏感性在 15 分钟时估计为 4% (95% CI 1-14)，在 25 分钟时为 10% (3-22) ，远低于90%的目标。使用血浆的实验室 RDT 显示出更好的灵敏度（15 分钟时为 46% [32–61]，25 分钟时为 50% [36–64]），但未达到目标灵敏度。 在 52 名患有拉沙热的 PCR 阳性参与者中，阳性 RDT 结果与较低的循环阈值相关（糖蛋白前体 [GPC] 基因平均值 30·3 [SD 4·3]，大 [L] 基因平均值 32·3 [3 ·7] GPC 基因平均值 24·5 [3·9]，L 基因平均值 28·0 [3·6]）。据报告，进行床边测试程序的人员因使用全套个人防护设备不方便以及在读取结果之前需要漫长的等待程序而受到阻碍。目前不建议将泛拉沙 RDT 作为疑似拉沙热病例的诊断或筛查工具。 RDT 的临床应用需要显着提高灵敏度和用户友好性。仍然迫切需要更好的拉沙热诊断，以促进院内护理的安全性和资源匮乏地区更好的疾病结果。无国界医生组织。