. 2021 May 31;93(9):5650–5654. doi: 10.1002/jmv.27089

Table 1.

Diagnostic performance of the evaluated Ag‐RDTs according to viral load

Type of sample	C _t values	Panbio		SD‐Biosensor		p value
PCR negative	N/A	Positive samples	0/186	Positive samples	5/186	0.063
PCR negative		Specificity	100.0	Specificity	97.3
(n = 186)					97.3
					(93.8–99.1)
			(98.0 – 100.0)		(93.8–99.1)
PCR positive	25.2 (20.2– 29.7)	Positive samples	102/170	Positive samples	113/170	0.003
PCR positive		Sensitivity	60.0	Sensitivity	66.5
(n = 170)		Sensitivity	(52.2 – 67.4)	Sensitivity	(58.8–73.5)
High viral load samples
C _t $\leq$ 20	17.8 (16.8– 18.5)	Positive samples	41/41	Positive samples	41/41	1.000
C _t $\leq$ 20		Sensitivity	100.0	Sensitivity	100.0
(n = 41)			(91.4 – 100.0)		100.0
(n = 41)			(91.4 – 100.0)		(91.4–100.0)
C _t = 20–25	22.1 (20.8– 23.6)	Positive samples	40/43	Positive samples	41/43	1.000
C _t = 20–25		Sensitivity	93.0	Sensitivity	95.3
(n = 43)	(80.9 – 98.5)	Sensitivity	(84.2–99.4)	Sensitivity	95.3
Low viral load samples
C _t = 25–30	27.2 (26.0– 28.7)	Positive samples	19/46	Positive samples	24/46	0.125
C _t = 25–30		Sensitivity	41.3	Sensitivity	52.2
(n = 46)		Sensitivity	(27.0 – 56.8)	Sensitivity	(36.9–67.1)
C _t > 30	31.3 (30.6 – 33.3)	Positive samples	2/40	Positive samples	7/40	0.063
(n = 40)		Sensitivity	5.0	Sensitivity	17.5
			5.0		(7.3–32.8)
			(0.6 – 16.9)		(7.3–32.8)

Note: Statistics: values are expressed as absolute count (percentage) and median (interquartile range). Sensitivity and specificity results are expressed as percentage with 95% CI. P‐values were calculated by the McNemar's test. Significant differences are shown in bold.

Abbreviations: Ag‐RDT, antigen rapid diagnostic test; C _t, cycle threshold; N/A, not applicable; 95% CI, 95% confidence interval; p‐value, level of significance.