TABLE 3.

LumiraDx SARS-CoV-2 Ag Test Performance in Cycle Threshold Subsets as Determined by the cobas 6800 SARS-CoV-2 Test (Roche Diagnostics), TaqPath COVID-19 Combo Kit (Thermo Fisher Scientific), and Either Reverse Transcription–Polymerase Chain Reaction Method

RT-PCR Test	Roche Diagnostics + Thermo Fisher Scientific		Roche Diagnostics		Thermo Fisher Scientific
Ct Value	No.	PPA (95% CI), %	No.	PPA (95% CI), %	No.	PPA (95% CI), %
<33	24	95.8 (79.8-99.3)	8	100 (67.6-100)	16	93.8 (71.7-98.9)
<30	22	100 (85.1-100)	7	100 (64.6-100)	15	100 (79.6-100)
<25	18	100 (82.4-100)	6	100 (61.0-100)	12	100 (75.8-100)

CI, confidence interval; COVID-19, coronavirus disease 2019; Ct, cycle threshold; PPA; positive percent agreement; RT-PCR, reverse transcription–polymerase chain reaction; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.