BACKGROUND PCR tests now outnumber antigen tests for the diagnosis of respiratory syncytial virus (RSV) infection in the US. Recent analyses have shown that the traditional 10% positivity threshold to define an RSV season by rapid antigen testing was inappropriate for real-time PCR testing, for which 3% positivity appeared more appropriate. OBJECTIVE To respectively model antigen (10%) and PCR (3%) positivity thresholds at national and regional levels using a large dataset of RSV testing results from US hospital-affiliated laboratories. STUDY DESIGN From 2011-2016, 599 laboratories participated in a national RSV surveillance program (RSVAlert®). For laboratories with ≥10 tests for ≥30 weeks of a season, national and regional test numbers and positivity were summarized by test type overall, by season, and weekly within each season. Test type positivity thresholds were used to calculate season onset and offset. RESULTS A seasonal average of 543,387 RSV tests was reported. PCR testing increased from 26% in 2011-2012 to 72% in 2015-2016. Overall, national positivity was 15.6% for antigen and 8.3% for PCR testing. National RSV season onsets and offsets were comparable using the 10% antigen and 3% PCR thresholds, but PCR-defined seasons generally started and ended later than antigen-defined seasons. Regionally, there were fewer outlier estimates of RSV season length when the predominant regional test type was used to define the season. CONCLUSION RSV positivity rates differed by test type, likely due to differential clinical use of the tests. These findings support the use of distinct positivity thresholds by test type.

中文翻译：

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在美国进行抗原和PCR检测的不同RSV季节性阈值的国家和地区建模。

背景技术现在，在美国，PCR检测的数量超过了用于诊断呼吸道合胞病毒（RSV）感染的抗原检测的数量。最近的分析表明，通过快速抗原检测来定义RSV季节的传统10％阳性阈值不适用于实时PCR检测，对于3％阳性看来更合适。目的使用来自美国医院附属实验室的大量RSV检测结果，分别在国家和地区级别对抗原（10％）和PCR（3％）阳性阈值进行建模。研究设计从2011年至2016年，有599个实验室参加了国家RSV监视计划（RSVAlert®）。对于一个季节中≥30周进行了≥10次检测的实验室，按总体检测类型，季节和每个季节中的每周总结国家和地区的检测数和阳性率。测试类型阳性阈值用于计算季节开始和偏移。结果报告了543,387例RSV检测的季节性平均值。PCR测试从2011-2012年的26％增加到2015-2016年的72％。总体而言，抗原的国家阳性率为15.6％，PCR检测的国家阳性率为8.3％。使用10％抗原和3％PCR阈值，全国RSV季节的发作和抵消是可比的，但是PCR定义的季节通常比抗原定义的季节开始和结束的时间晚。在区域上，当使用主要的区域测试类型来定义季节时，对RSV季节长度的异常估计更少。结论RSV阳性率因测试类型而异，这可能是由于测试的临床用途不同所致。这些发现支持按测试类型使用不同的阳性阈值。