TABLE 3.

Analytical sensitivity (50% and 95% detection limits) of NAT systems on (dilutions of) the Eurohep HBV DNA genotype A2 standard, Ultrio HBV NAT–yield samples, and HBsAg-positive and Ultrio initially nonreactive samples as determined by parallel line probit analysis

				LOD (copies/mL)
	Number of			Ultrio		Ultrio Plus		TaqScreen
	Samples	Dilutions	Replicates	50% (CI)	95% (CI)	50% (CI)	95% (CI)	50% (CI)	95% (CI)
Eurohep standard	1	10	24	9.3 (6.4–13.7)	90.2 (55.9–165)	4.5 (3.0–6.6)	43.1 (26.8–77.9)	2.2 (1.3–3.9)	21.4 (11.7–43.8)
HBV NAT yields	107	3	6	10.6 (9.2–12.3)	120 (94.8–157)	4.3 (3.7–5.0)	48.7 (39.3–62.2)	4.6 (3.6–5.9)	51.7 (38.3–71.7)
HBsAg yields	32	1*	12	375 (156–1267)	1248 (564–3974)	4.0 (2.8–5.6)	34.8 (26.8–139)	2.5 (1.4–4.1)	37.9 (20.6–89.2)

^*Eight samples that were 100% reactive in Ultrio Plus and TaqScreen were tested in 1:8 dilution to compare percentage response in these assays with that on the undiluted samples in the Ultrio assay.