Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda
Infectious Diseases Institute, College of Health Sciences, Makerere University, Kampala, Uganda.
J Clin Microbiol. 2021 Feb 18;59(3). doi: 10.1128/JCM.02421-20.
Cryptococcal meningitis is a leading cause of meningitis in sub-Saharan Africa. Given the need for rapid point-of-care testing, we evaluated the diagnostic performance of the Dynamiker cryptococcal antigen (CrAg) lateral flow assay (LFA). We assessed the diagnostic performance of the Dynamiker CrAg LFA compared to the IMMY CrAg LFA as the reference standard. We tested 150 serum, 115 plasma, and 100 cerebrospinal fluid (CSF) samples from HIV patients with symptomatic meningitis and 113 serum samples from patients with suspected asymptomatic cryptococcal antigenemia. Compared to the IMMY CrAg LFA, sensitivity of Dynamiker CrAg LFA was 98% in serum, 100% in plasma, 100% in CSF from symptomatic patients and 96% in serum from asymptomatic patients. Specificity was 66% in serum, 61% in plasma, and 91% in CSF from symptomatic patients, and 86% in serum from asymptomatic patients. The positive predictive value was 85% in serum, 82% in plasma, and 96% in CSF from symptomatic patients, and 69% in serum from asymptomatic patients. The negative predictive value was 94% in serum, 100% in plasma, and 100% in CSF from symptomatic patients, and 99% in serum from asymptomatic patients. The interassay reproducibility was 100% across the four sample types with no observed discordant results when Dynamiker CrAg LFA was tested in duplicate. However, a high number of false positives were observed on serum of symptomatic patients (11%), serum of asymptomatic patients (11%) and plasma of symptomatic patients (14%). The Dynamiker CrAg LFA had excellent sensitivity but poor specificity, particularly when tested on serum and plasma.
隐球菌性脑膜炎是撒哈拉以南非洲地区脑膜炎的主要病因。鉴于需要快速进行床边检测，我们评估了 Dynamiker 隐球菌抗原（CrAg）侧向流动检测（LFA）的诊断性能。我们评估了 Dynamiker CrAg LFA 与 IMMY CrAg LFA 作为参考标准的诊断性能。我们检测了 150 份血清、115 份血浆和 100 份脑脊液（CSF）样本，这些样本来自有症状脑膜炎的 HIV 患者，以及 113 份来自疑似无症状隐球菌抗原血症患者的血清样本。与 IMMY CrAg LFA 相比，Dynamiker CrAg LFA 在血清中的敏感性为 98%，在血浆中的敏感性为 100%，在有症状患者的 CSF 中的敏感性为 100%，在无症状患者的血清中的敏感性为 96%。在血清中的特异性为 66%，在血浆中的特异性为 61%，在有症状患者的 CSF 中的特异性为 91%，在无症状患者的血清中的特异性为 86%。在有症状患者的血清中的阳性预测值为 85%，在血浆中的阳性预测值为 82%，在 CSF 中的阳性预测值为 96%，在无症状患者的血清中的阳性预测值为 69%。在血清中的阴性预测值为 94%，在血浆中的阴性预测值为 100%，在有症状患者的 CSF 中的阴性预测值为 100%，在无症状患者的血清中的阴性预测值为 99%。在四种样本类型中，Dynamiker CrAg LFA 的检测结果具有良好的重复性，在进行重复检测时未观察到不一致的结果。然而，在有症状患者的血清（11%）、无症状患者的血清（11%）和有症状患者的血浆（14%）中观察到大量假阳性。Dynamiker CrAg LFA 的敏感性非常好，但特异性较差，特别是在检测血清和血浆时。
