Department of Health Services, Policy, and Practice, Brown University School of Public Health, Providence, RI, USA.
Department of Health Services, Policy, and Practice, Brown University School of Public Health, Providence, RI, USA.
J Am Med Dir Assoc. 2022 Aug;23(8):1279-1282. doi: 10.1016/j.jamda.2022.06.006. Epub 2022 Jun 20.
Reverse transcription polymerase chain reaction (PCR) and antigen tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are sometimes discordant. We evaluated the discordance between antigen and PCR tests sampled in skilled nursing facilities (SNFs) to assess the relationship of symptom presence, timing between tests, and the presence of a facility outbreak.
Observational study using electronic health record data.
Residents of 306 SNFs in 23 states, operated by 1 company.
We identified all rapid antigen and PCR tests conducted in study SNFs as of January 10, 2021, and classified whether symptoms were present and whether the facility was in outbreak at time of testing. We calculated the proportions of antigen tests with discordant follow-up PCR results conducted no more than 2 days after the antigen test.
Of the 171,280 antigen tests in 34,437 SNF residents, 20,991 (12.3%) were followed by a PCR test within 2 days. A total of 1324 negative antigen tests were followed by a positive PCR result, representing 0.8% of all antigen tests and 6.3% of repeated antigen tests; while 337 positive antigen tests were followed by a negative PCR result, representing 0.2% of all antigen tests and 1.6% of repeated antigen tests. Discordance more often occurred when residents were symptomatic at time of antigen testing, during known facility outbreaks, and when the antigen test was compared with a PCR test done within 2 days vs 1 day.
Overall, discordance between SARS-CoV-2 antigen and PCR tests was low. Discordance was more common when the individual was symptomatic at time of antigen testing and during facility outbreaks. This suggests that a testing strategy which couples widespread use of antigen tests with clinical thresholds to conduct follow-up confirmatory PCR testing appears to perform well in SNFs, where timely and accurate SARS-CoV-2 case identification are critical.
逆转录聚合酶链反应（PCR）和严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）抗原检测有时不一致。我们评估了在熟练护理机构（SNF）中采样的抗原和 PCR 检测之间的不一致性，以评估症状存在、检测之间的时间以及设施暴发的存在之间的关系。
使用电子健康记录数据的观察性研究。
来自 23 个州的 306 个 SNF 的居民，由 1 家公司运营。
我们确定了截至 2021 年 1 月 10 日在研究 SNF 中进行的所有快速抗原和 PCR 检测，并对检测时是否存在症状以及设施是否发生暴发进行了分类。我们计算了在抗原检测后不超过 2 天进行的具有不一致后续 PCR 结果的抗原检测的比例。
在 34437 名 SNF 居民的 171280 次抗原检测中，有 20991 次（12.3%）在 2 天内进行了 PCR 检测。共有 1324 次阴性抗原检测后出现阳性 PCR 结果，占所有抗原检测的 0.8%和重复抗原检测的 6.3%；而 337 次阳性抗原检测后出现阴性 PCR 结果，占所有抗原检测的 0.2%和重复抗原检测的 1.6%。当居民在抗原检测时出现症状、在已知的设施暴发期间以及当抗原检测与 2 天内 vs 1 天内进行的 PCR 检测进行比较时，抗原和 PCR 检测之间的不一致更为常见。
总体而言，SARS-CoV-2 抗原和 PCR 检测之间的不一致性较低。当个体在抗原检测时出现症状和设施暴发期间，不一致性更为常见。这表明，在熟练护理机构中，广泛使用抗原检测并结合临床阈值来进行后续确认性 PCR 检测的检测策略似乎表现良好，在熟练护理机构中，及时准确地识别 SARS-CoV-2 病例至关重要。
