Diagnostic Performance Characteristics of the Operators’ ICT
Kits Based on rRT-PCR Ct Value Categories
To determine the diagnostic performance characteristics of the test kits
in comparison with viral load, the cycle threshold (Ct) values were
classified into 19.00 – 29.99, 30.00 – 34.99 and >35.00
to determine the threshold at which the test kits would have the best
performance.
The results show that the DG Rapid and SD Rapid kits had higher
sensitivity and Cohen’s kappa coefficient than the SS Rapid kit in
detecting SARS-CoV-2 across all Ct value categories. However, all three
kits showed high specificity and PPV in all Ct value categories.
Specifically, Cohen’s kappa coefficient indicated substantial or
excellent agreement between the ICT kits and rRT-PCR results at lower Ct
values (19.00 - 29.99 and 30.00 - 34.99) for the DG Rapid and SD Rapid
kits, but only good agreement for the SS Rapid kit. However, for Ct
values >35.00, all three kits had poor agreement with
rRT-PCR.