Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA.
Center for Individualized Medicine, Bangalore, Mayo Clinic, Rochester, MN, USA.
Clin Chem. 2021 Nov 1;67(11):1545-1553. doi: 10.1093/clinchem/hvab138.
We evaluated the analytical sensitivity and specificity of 4 rapid antigen diagnostic tests (Ag RDTs) for severe acute respiratory syndrome coronavirus 2, using reverse transcription quantitative PCR (RT-qPCR) as the reference method and further characterizing samples using droplet digital quantitative PCR (ddPCR) and a mass spectrometric antigen test.
Three hundred fifty (150 negative and 200 RT-qPCR positive) residual PBS samples were tested for antigen using the BD Veritor lateral flow (LF), ACON LF, ACON fluorescence immunoassay (FIA), and LumiraDx FIA. ddPCR was performed on RT-qPCR-positive samples to quantitate the viral load in copies/mL applied to each Ag RDT. Mass spectrometric antigen testing was performed on PBS samples to obtain a set of RT-qPCR-positive, antigen-positive samples for further analysis.
All Ag RDTs had nearly 100% specificity compared to RT-qPCR. Overall analytical sensitivity varied from 66.5% to 88.3%. All methods detected antigen in samples with viral load >1 500 000 copies/mL RNA, and detected ≥75% of samples with viral load of 500 000 to 1 500 000 copies/mL. The BD Veritor LF detected only 25% of samples with viral load between 50 000 to 500 000 copies/mL, compared to 75% for the ACON LF device and >80% for LumiraDx and ACON FIA. The ACON FIA detected significantly more samples with viral load <50 000 copies/mL compared to the BD Veritor. Among samples with detectable antigen and viral load <50 000 copies/mL, sensitivity of the Ag RDT varied between 13.0% (BD Veritor) and 78.3% (ACON FIA).
Ag RDTs differ significantly in analytical sensitivity, particularly at viral load <500 000 copies/mL.
我们使用逆转录定量 PCR（RT-qPCR）作为参考方法，对 4 种快速抗原诊断检测（Ag RDT）针对严重急性呼吸综合征冠状病毒 2 的分析灵敏度和特异性进行了评估，并进一步使用液滴数字定量 PCR（ddPCR）和质谱抗原检测对样本进行了特征分析。
用 BD Veritor 侧向流动（LF）、ACON LF、ACON 荧光免疫分析（FIA）和 LumiraDx FIA 对 350 个（150 个阴性和 200 个 RT-qPCR 阳性）残留 PBS 样本进行抗原检测。对 RT-qPCR 阳性样本进行 ddPCR，以定量应用于每个 Ag RDT 的拷贝/mL 的病毒载量。对 PBS 样本进行质谱抗原检测，获得一组 RT-qPCR 阳性、抗原阳性的样本进行进一步分析。
与 RT-qPCR 相比，所有 Ag RDT 的特异性均接近 100%。总体分析灵敏度从 66.5%到 88.3%不等。所有方法均在病毒载量>150 万拷贝/mL RNA 的样本中检测到抗原，并检测到 50 万至 150 万拷贝/mL 病毒载量的样本中≥75%。BD Veritor LF 仅检测到 50 万至 500 万拷贝/mL 病毒载量的样本的 25%，而 ACON LF 设备检测到 75%，LumiraDx 和 ACON FIA 检测到>80%。ACON FIA 检测到的病毒载量<50 000 拷贝/mL 的样本明显多于 BD Veritor。在可检测抗原和病毒载量<50 000 拷贝/mL 的样本中，Ag RDT 的灵敏度在 13.0%（BD Veritor）至 78.3%（ACON FIA）之间变化。
Ag RDT 在分析灵敏度方面存在显著差异，尤其是在病毒载量<500 000 拷贝/mL 时。
