Table 3. .

Percentage of Single-Positive Specimens With Ct Values Within the Shifted Range^a

Prevalence Groupb	No.	Shifted Range (N1)	Shifted Totals (N1)	% Shifted (N1)c	Shifted Range (N3)	Shifted Totals (N3)	% Shifted (N3)c
1	820	37.0–40	22	2.7 [1.8–4.0]	37.5–40	0	0.0 [0.0–0.69]
2	1113	38.3–40	7	0.63 [0.3–1.3]	38.7–40	0	0.0 [0.0–0.51]
3	1158	37.6–40	17	1.5 [0.9–2.3]	38.1–40	0	0.0 [0.0–0.49]
All groups combined	3091		46	1.5 [1.1–2.0]		0	0.0 [0.0–0.18]

Abbreviation: Ct, cycle threshold.

^aThe shift in N1 and N3 Ct values for pooled testing was calculated from Passing-Bablok regression analysis of pooled and singlicate positive specimens. Shift = (40 – intercept)/slope. The number of single-positive specimens with Ct values in the range of 40 – shift_N1 and 40 – shift_N3 was then tabulated.

^bSpecimens were drawn from 3 geographic prevalence groups, as described in the “Methods” section.

^cShown as value [95% CI].