ddPCR: a more accurate tool for SARS-CoV-2 detection in low viral load specimens
ddPCR: a more accurate tool for SARS-CoV-2 detection in low viral load specimens
复制标题
ddPCR：一种在低病毒载量样本中检测 SARS-CoV-2 的更准确工具。
DOI：
10.1080/22221751.2020.1772678
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发表时间：
2020-01-01
影响因子：
13.2
通讯作者：
Chen, Yu
中科院分区：
文献类型：
--
作者：
Suo, Tao;Liu, Xinjin;Chen, Yu
实时定量PCR （RT-PCR）被广泛用作临床检测SARS-CoV-2的金标准。然而，由于病毒载量较低的标本和RT-PCR的局限性，不可避免地出现大量假阴性报告，导致无法及时诊断，切断传播，评估出院标准。为改善这一情况，采用优化后的液滴数字PCR （ddPCR）检测SARS-CoV-2，结果表明，ddPCR的检出限明显低于RT-PCR。我们进一步探讨了ddPCR检测77例患者SARS-CoV-2 RNA的可行性，并根据随访调查结果与RT-PCR进行诊断准确性比较。26例RT-PCR阴性患者经ddPCR检测为阳性。RT-PCR的灵敏度、特异性、PPV、NPV、阴性似然比（NLR）和准确性分别从40% （95% CI: 27-55%）、100% （95% CI: 54-100%）、100%、16% （95% CI: 13-19%）、0.6 （95% CI: 0.48-0.75）和47% （95% CI: 33-60%）提高到94% （95% CI: 83-99%）、100% （95% CI: 48-100%）、100%、63% （95% CI: 36-83%）、0.06 （95% CI: 0.02-0.18）和95% （95% CI: 84-99%）。出院后5-12天，6/14（42.9%）患者的ddPCR检测呈阳性。综上所述，ddPCR在临床诊断SARS-CoV-2方面具有优势，可减少假阴性报告，可作为RT-PCR的有力补充。
Quantitative real time PCR (RT-PCR) is widely used as the gold standard for clinical detection of SARS-CoV-2. However, due to the low viral load specimens and the limitations of RT-PCR, significant numbers of false negative reports are inevitable, which results in failure to timely diagnose, cut off transmission, and assess discharge criteria. To improve this situation, an optimized droplet digital PCR (ddPCR) was used for detection of SARS-CoV-2, which showed that the limit of detection of ddPCR is significantly lower than that of RT-PCR. We further explored the feasibility of ddPCR to detect SARS-CoV-2 RNA from 77 patients, and compared with RT-PCR in terms of the diagnostic accuracy based on the results of follow-up survey. 26 patients of COVID-19 with negative RT-PCR reports were reported as positive by ddPCR. The sensitivity, specificity, PPV, NPV, negative likelihood ratio (NLR) and accuracy were improved from 40% (95% CI: 27-55%), 100% (95% CI: 54-100%), 100%, 16% (95% CI: 13-19%), 0.6 (95% CI: 0.48-0.75) and 47% (95% CI: 33-60%) for RT-PCR to 94% (95% CI: 83-99%), 100% (95% CI: 48-100%), 100%, 63% (95% CI: 36-83%), 0.06 (95% CI: 0.02-0.18), and 95% (95% CI: 84-99%) for ddPCR, respectively. Moreover, 6/14 (42.9%) convalescents were detected as positive by ddPCR at 5-12 days post discharge. Overall, ddPCR shows superiority for clinical diagnosis of SARS-CoV-2 to reduce the false negative reports, which could be a powerful complement to the RT-PCR.