Multiple rapid antigen (Ag) tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have recently received emergency-use authorization (EUA) from the U.S. Food and Drug Administration (FDA). Although less sensitive than molecular detection methods, rapid antigen testing offers the potential for inexpensive, quick, decentralized testing. Robust analytical sensitivity data in comparison to reverse transcription-quantitative PCR (qRT-PCR) are currently lacking for many rapid antigen tests. Here, we evaluated the analytical sensitivity of the Abbott BinaxNOW COVID-19 Ag card using SARS-CoV-2-positive clinical specimens quantified by reverse transcription-droplet digital PCR (RT-ddPCR) and multiple FDA EUA qRT-PCR platforms using RNA standards. Initial and confirmatory limits of detection for the BinaxNOW COVID-19 Ag card were determined to be equivalent to 4.04 × 10⁴ to 8.06 × 10⁴ copies/swab. We further confirmed this limit of detection with 72 additional clinical samples positive for SARS-CoV-2 in either phosphate-buffered saline or viral transport medium. One hundred percent of samples with viral loads of >40,000 copies/swab were detected by rapid antigen testing. These data indicate that the BinaxNOW COVID-19 Ag card has an analytical sensitivity approximately equivalent to a generic qRT-PCR cycle threshold (C_T) value of 29 to 30.

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雅培BinaxNOW COVID-19 Ag卡的分析灵敏度

严重急性呼吸系统综合症冠状病毒2（SARS-CoV-2）的多项快速抗原（Ag）测试最近已获得美国食品和药物管理局（FDA）的紧急使用授权（EUA）。尽管不如分子检测方法灵敏，但是快速抗原检测为廉价，快速，分散的检测提供了潜力。与许多快速抗原测试相比，与逆转录定量PCR（qRT-PCR）相比，目前缺乏可靠的分析灵敏度数据。在这里，我们使用SARS-CoV-2阳性临床标本（通过逆转录液滴数字PCR（RT-ddPCR）定量）和多个FDA EUA qRT-PCR平台（使用RNA标准）对Abbott BinaxNOW COVID-19 Ag卡的分析灵敏度进行了评估。⁴至8.06×10 ⁴份/拭子。我们用磷酸盐缓冲液或病毒运输培养基中的SARS-CoV-2阳性的72个其他临床样品进一步证实了这种检测限。通过快速抗原测试检测到病毒载量> 40,000拷贝/拭子的样本中有100％。这些数据表明BinaxNOW COVID-19 Ag卡的分析灵敏度大约等于29至30的通用qRT-PCR循环阈值（C _T）值。