Virology and Immunology Department, LabPLUS, Auckland City Hospital, Auckland, New Zealand.
Labtests, Auckland, New Zealand.
N Z Med J. 2021 Nov 26;134(1546):28-37.
To assess the sensitivity and potential utility of five RATs and the IDNow, Liat and Oxsed nucleic acid amplification tests (NAATs) in our population.
39 retrospective and contrived SARS-CoV-2 positive samples were tested in parallel by standard RT-PCR and RAT. A second group of 44 samples was tested by standard RT-PCR, rapid RT-PCR and two isothermal NAAT assays. Limit of detection was compared at RT-PCR cycle thresholds for all assays.
We found that the Cobas Liat RT-PCR had 100% concordance with conventional RT-PCR, whereas the sensitivity of other rapid NAAT assays was less at lower viral loads indicated by Cts >30 (p=0.042) and the RATs at Cts >25 (p<0.001). When applied to New Zealand testing scenarios, IDNow or Oxsed NAAT could miss up to 12% and RATs up to 44.3% of COVID-19 cases compared with the RT-PCR currently used at our laboratory.
We found that the POC Cobas Liat, a platform that delivers a sample answer in 20 minutes, demonstrated equivalent performance to standard RT-PCR. However, the RATs and isothermal NAAT assays demonstrated reduced sensitivity, limiting their utility in New Zealand's currently very low prevalence setting.
评估五种 RAT 和 IDNow、Liat 和 Oxsed 核酸扩增检测（NAAT）在本人群中的敏感性和潜在应用价值。
39 份回顾性和人工 SARS-CoV-2 阳性样本同时用标准 RT-PCR 和 RAT 进行平行检测。第二组 44 个样本同时用标准 RT-PCR、快速 RT-PCR 和两种等温 NAAT 检测进行检测。对所有检测的 RT-PCR 循环阈值进行了检测限比较。
我们发现 Cobas Liat RT-PCR 与常规 RT-PCR 具有 100%的一致性，而其他快速 NAAT 检测的敏感性在较低的病毒载量下较低，Ct 值>30（p=0.042），RAT 的 Ct 值>25（p<0.001）。当应用于新西兰检测场景时，IDNow 或 Oxsed NAAT 与我们实验室目前使用的 RT-PCR 相比，可能会漏检多达 12%的 COVID-19 病例，而 RAT 会漏检多达 44.3%的 COVID-19 病例。
我们发现 POCT Cobas Liat 在 20 分钟内提供样本答案，其性能与标准 RT-PCR 相当。然而，RAT 和等温 NAAT 检测的敏感性降低，限制了它们在新西兰目前极低流行率环境下的应用价值。
