TABLE 4.
Agreement between the GeneXpert Ebola assay and the L gene qRT-PCR on the LightCycler Nano and the SmartCycler at different CT value ranges, using clinical samples collected from suspected EVD cases in Freetown, Sierra Leone from 2014 to 2015
| SmartCycler L gene qRT-PCR CT value range (no. of samples) | GeneXpertEbola assaya |
LightCycler Nano L gene qRT-PCRa |
||||||
|---|---|---|---|---|---|---|---|---|
| GP target |
NP target |
One or both targets (GP and NP) |
||||||
| + | − | + | − | + | − | + | − | |
| CT < 30 (n = 81) | 81 | 0 | 81 | 0 | 81 | 0 | 81 | 0 |
| 100%b | 100% | 100% | 100% | |||||
| CT 30–34.99 (n = 15) | 15 | 0 | 15 | 0 | 15 | 0 | 15 | 0 |
| 100% | 100% | 100% | 100% | |||||
| CT 35–39.99 (n = 16) | 9 | 7 | 15 | 1 | 15 | 1 | 15 | 1 |
| 56.25% | 93.75% | 93.75% | 93.75% | |||||
| CT 40–45 (n = 10) | 2 | 8 | 9 | 1 | 10 | 0 | 9 | 1 |
| 20.0% | 90.0% | 100% | 90.0% | |||||
| No fluorescence signal above the threshold (n = 159) | 2 | 157 | 3 | 156 | 4 | 155 | 1 | 158 |
| 98.74% | 98.11% | 97.48% | 99.37% | |||||
a
+, Positive; −, negative.
b
Percentage agreement between applicable assay and SmartCycler L gene qRT-PCR using a cutoff CT of 45.