Naval Medical Research Center, Silver Spring, Maryland, United States of America.
Department of Parasitology, U.S Naval Medical Research Unit No. 6, Callao, Lima, Peru.
PLoS Negl Trop Dis. 2023 Mar 13;17(3):e0011054. doi: 10.1371/journal.pntd.0011054. eCollection 2023 Mar.
Cutaneous leishmaniasis (CL) is a neglected disease and a public health problem in Latin America. The diagnosis of CL in poor hyperendemic regions relies to large extent on the identification of amastigotes in Giemsa-stained smears. There is an urgent need for a rapid, sensitive and low cost diagnostic method for use in field conditions for CL as current modalities are not readily available. The primary objective of this study was to determine the sensitivity and specificity of the FDA-cleared CL Detect Rapid Test in Peru, using modified test procedures rather than the instructions-for-use, by 1) increasing the extraction time and 2) increasing the volume of the sample added to the test strip. CL Detect Rapid Test results were compared against microscopy and kDNA-PCR, for the diagnosis of CL in ulcerated lesions. In addition, we compared two collection methods the dental broach used and mentioned in the CL Detect insert and the standard less invasive and easier to conduct scrapping method.
Participants were patients who presented for medical consultation due to a suspected CL lesion. Four samples from the index lesion were collected using a dental broach, per package insert, and lancet scraping and tested by the modified CL Detect Rapid Test, microscopy, and PCR.
A total of 156 subjects were eligible and evaluated. The modified CL Detect sensitivity was higher in specimens obtained by scraping (83.3%) than those from dental broach (64.2%). The specificity was lower in scrapings (77.8%) with a false positive rate of 22.2% compared with dental broach samples (91.7%) with a false positive rate of 8.3%. However, molecular analysis showed that all 8 false negative microscopy scrapings (those positive by modified CL Detect and negative by microscopy) were positive by kDNA-PCR, meaning that the modified CL Detect was more sensitive than microscopy.
These modifications to the package insert that resulted in a diagnostic sensitivity (83.3%) comparable to microscopy for species found in Peru may enable earlier anti-leishmanial drug treatment decisions based on a positive result from the CL Detect Rapid Test alone until further diagnostic tests like microscopy and PCR can be performed.
NCT03762070; Clinicaltrials.gov.
皮肤利什曼病（CL）是拉丁美洲被忽视的疾病和公共卫生问题。在高流行地区的贫困地区，CL 的诊断在很大程度上依赖于对吉姆萨染色涂片中小体的识别。迫切需要一种快速、敏感和低成本的诊断方法，用于现场条件下的 CL，因为目前的方法不容易获得。本研究的主要目的是通过以下两种方式确定经 FDA 批准的 CL 检测快速检测在秘鲁的灵敏度和特异性：1）增加提取时间和 2）增加添加到检测条的样本量。使用修改后的测试程序而不是使用说明，将 CL 检测快速检测结果与显微镜和 kDNA-PCR 进行比较，用于诊断溃疡性病变的 CL。此外，我们比较了两种采集方法，一种是牙科锉，另一种是 CL 检测插页中提到的标准非侵入性且更容易进行的刮擦方法。
参与者是因疑似 CL 病变而就诊的患者。根据包装说明书，使用牙科锉从索引病变处采集 4 个样本，并使用改良 CL 检测快速检测、显微镜和 PCR 进行检测。
共有 156 名符合条件的受试者接受了评估。用刮擦法获得的标本的改良 CL 检测灵敏度（83.3%）高于牙科锉（64.2%）。刮擦法的特异性较低（77.8%），假阳性率为 22.2%，而牙科锉样本的特异性较高（91.7%），假阳性率为 8.3%。然而，分子分析显示，所有 8 个经改良 CL 检测阳性但显微镜检查为阴性的假阴性刮屑均通过 kDNA-PCR 呈阳性，这意味着改良 CL 检测比显微镜检查更敏感。
这些对包装说明书的修改使诊断灵敏度（83.3%）与秘鲁发现的物种的显微镜检查相当，这可能使基于 CL 检测快速检测的阳性结果而更早地做出抗利什曼药物治疗决策成为可能，直到可以进行进一步的诊断测试，如显微镜检查和 PCR。
NCT03762070；Clinicaltrials.gov。
