Skip to main content
. 2020 Nov 23;70(1):7–20. doi: 10.2144/btn-2020-0133

Figure 5. . End point dPCR assay results on contrived clinical sample consisting of independent donor samples.

Figure 5. 

(A) End point dPCR system detection result of negative samples (30 replicates), 1.5 × LoD samples (4.5 copies per reaction, 20 replicates) and 4 × LoD samples (12 copies per reaction, 10 replicates). Expected sample types were plotted on the X-axis versus measured values of FAM positive signals on the Y-axis, targeting the N gene of SARS-CoV-2. All the negative samples were called as negative; the positive rates of 1.5 × LoD and 4 × LoD samples were 95 and 100%, respectively. (B) FAM positive signals distribution of these samples by end point dPCR. Expected sample types were plotted on the X-axis versus measured values of FAM positive signals on the Y-axis, targeting the N gene of SARS-CoV-2. All 30 negative samples were true negative but contain 1–2 false-positive FAM signals; the 1.5 × LoD samples (20 samples) produced 19 (95%) true positives with 1 false negative. All samples at the 4 × LoD concentration were called as positive. Mean and coefficient of variation values for negative, 1–2 × LoD and 3–5 × LoD samples were 0.90 (82.90%), 6.20 (30.86%) and 17.50 (14.06%), respectively.

LoD: Limit of detection.