A multiple center clinical evaluation of an ultra-fast single-tube assay for SARS-CoV-2 RNA

Wang, Ji; Cai, Kun; He, Xiaozhou; Shen, Xinxin; Wang, Jinrong; Liu, Jun; Xu, Junqiang; Qiu, Feng; Lei, Wenwen; Cui, Lunbiao; Ge, Yiyue; Wu, Tao; Zhang, Yanjun; Yan, Hao; Chen, Yin; Yu, Jiezhong; Ma, Xiaojun; Shi, Hua; Zhang, Ruiqing; Li, Xinna; Gao, Yuan; Niu, Peihua; Tan, Wenjie; Wu, Guizhen; Jiang, Yongzhong; Xu, Wenbo; Ma, Xuejun

OBJECTIVES: To evaluate the performance of an ultra-fast single-tube nucleic acid isothermal amplification detection assay for SARS-CoV-2 RNA using clinical samples from multiple centers. METHODS: A reverse transcription recombinase-aided amplification (RT-RAA) assay for SARS-CoV-2 was conducted within 15minutesat39°C with portable instruments after addition of extracted RNA. The clinical performance of RT-RAA assay was evaluated using 947 clinical samples from five institutions in four regions of China, and the approved commercial real-time fluorescent RT-PCR (qRT-PCR) kits were used for parallel detection. The sensitivity and specificity of RT-RAA were compared and analyzed. RESULTS: The RT-RAA test results of 926 samples were consistent with those of qRT-PCR (330 were positive, 596 were negative) and 21 were inconsistent. The sensitivity and specificity of RT-RAA was 97.63% [330/338, 95% confidence interval (CI): 95.21 to 98.90] and 97.87% (596/609, 95% CI: 96.28 to 98.81), respectively. The positive predictive value (PPV) and negative predictive value (NPV) were 96.21% (330/343, 95% CI: 93.45 to 97.88), and 98.68% (596/604, 95% CI: 97.30 to 99.38), respectively. The total coincidence rate was 97.78% (926/947, 95% CI: 96.80 to 98.70) and the Kappa was 0.952 (P <0.05). CONCLUSION: With comparable sensitivity and specificity to the commercial qRT-PCR kits, RT-RAA assay for SARS-CoV-2 exhibited distinctive advantages of simplicity and rapidity in terms of operation and turn-around time.