Table 2 Clinical sample evaluation of the colorimetric RT-LAMP assay developed for Delta variant (B.1.617.2) of SARS-CoV-2.

From: A colorimetric reverse-transcription loop-mediated isothermal amplification method targeting the L452R mutation to detect the Delta variant of SARS-CoV-2

 

Real-time RT-PCR

Total

Positive samples

Negative samples

Colorimetric RT-LAMP positive

66

0

66

Colorimetric RT-LAMP negative

2

58

60

Total

68

58

126

  1. True Positive (TP) = 66 (the colorimetric RT-LAMP assay showed positive results that were similarly positive in real-time RT-PCR). False Positive (FP) = 0 (the colorimetric RT-LAMP assay showed positive results but was negative for real-time RT-PCR). True Negative (TN) = 58 (the colorimetric RT-LAMP assay showed negative results that were similarly negative in real-time RT-PCR). False Negative (FN) = 2 (the colorimetric RT-LAMP assay showed negative results but was positive for real-time RT-PCR). Positive Predictive Value (PPV) = TP/(TP + FP) = 66/(66 + 0) = 1.000 = 100.00%. Negative Predictive Value (NPV) = TN/(TN + FN) = 58/(58 + 2) = 0.9667 = 96.67%. Sensitivity = TP/(TP + FN) = 66/(66 + 2) = 0.9706 = 97.06%. Specificity = TN/(TN + FP) = 58/(58 + 0) = 1.000 = 100.00%. Accuracy = (TP + TN)/(TP + TN + FP + FN) = (66 + 58)/(66 + 58 + 0 + 2) = 0.9841 = 98.41%.
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