Department of Clinical Virology, Institute of Liver and Biliary Sciences, New Delhi, India.
Department of Clinical Virology, Institute of Liver and Biliary Sciences, New Delhi, India.
Indian J Med Microbiol. 2021 Apr;39(2):231-234. doi: 10.1016/j.ijmmb.2020.11.002. Epub 2021 Jan 27.
Pool testing is one of the strategy to expedite testing capacities while simultaneously conserving various diagnostic kits, reagents and consumables and time. In the present study, we investigated potential role of combined specimen collection technique for the diagnosis of SARS-CoV-2 virus infection where five nasopharyngeal swabs were collected from different individuals and pooled together in a single viral transport medium (VTM).
This pilot study was conducted on different cohorts of Delhi state. Two nasopharyngeal swabs were collected from each enrolled individual. One swab was put into VTM vial to be further used for individual swab testing (ID). The other swab was put into a fresh VTM for pool swab collection. Each pool comprised five swabs collected from five different patients in one VTM vial. Both IDs and pools were tested in parallel for the detection of SARS-CoV-2 using real time PCR.
A total of 46 pools were collected from 230 enrolled individuals.Among 230 ID tested, 60 were found to be positive for both E and RdRp gene. Among 46 pools, 25 pools included all negatives samples and remaining 21 pools included one or more positives. Comparing ID with pool results, overall concordance was seen in 42 pools (91.3%). Four pools showed false positive results as all included samples on ID testing were found to be negative. Considering ID results as reference, swab pool showed 100% sensitivity, 84% specificity, 84% positive predictive value and 100% negative predictive value.
The pooling of swab strategy could be beneficial only among asymptomatic in low prevalence areas.
池检测是一种加快检测能力的策略，同时可以节约各种诊断试剂盒、试剂和耗材，以及时间。在本研究中，我们研究了联合标本采集技术在 SARS-CoV-2 病毒感染诊断中的潜在作用，其中从五个不同个体采集五个鼻咽拭子并合并在一个单一的病毒运输介质（VTM）中。
这项初步研究是在德里邦的不同队列中进行的。从每个入组个体中采集两个鼻咽拭子。一个拭子放入 VTM 小瓶中，用于个体拭子检测（ID）。另一个拭子放入新的 VTM 中用于池拭子采集。每个池由五个不同患者的五个拭子组成，放置在一个 VTM 小瓶中。ID 和池平行进行实时 PCR 检测，以检测 SARS-CoV-2 的存在。
从 230 名入组个体中采集了 46 个池。在 230 个 ID 测试中，有 60 个同时对 E 和 RdRp 基因呈阳性。在 46 个池中，25 个池均包含阴性样本，其余 21 个池包含一个或多个阳性样本。将 ID 与池结果进行比较，在 42 个池中观察到总体一致性（91.3%）。四个池显示出假阳性结果，因为在 ID 测试中所有包含的样本均为阴性。以 ID 结果为参考，拭子池显示出 100%的敏感性、84%的特异性、84%的阳性预测值和 100%的阴性预测值。
在低流行地区，仅在无症状个体中，拭子池策略可能有益。
