Table 2.

Estimated LoD for detection of influenza A subtype or influenza B lineages

Virus	LoD in copies/reaction* (95 % CI)
	RV15	Real-time RT-PCR influenza A/B detection	Real-time RT-PCR influenza A H1/H3 subtyping	Real-time RT-PCR influenza B Yamagata/Victoria lineage
FluA H1N1	4.0 (3.2–6.8)	1.5 (1.2–2.5)	9.5 (7.0–12.2)	na
FluA H3N2	4.2 (2.2–5.6)	0.9 (0.7–1.3)	0.9 (0.7–1.3)	na
FluB Yamagata	5.2 (4.0–6.4)	0.4 (0.1–0.6)	na	25.0 (22.6–26.6)
FluB Victoria	3.2 (3.0–3.4)	1.5 (1.1–1.4)	na	3.2 (2.6–3.9)

*The concentration that could reproducibly (at 95 % confidence) be detected by the test method is described as the LoD. The LoD was determined by Probit analysis by testing replicate aliquots of virus dilutions (see Table S3). For each virus aliquot, the C _t values obtained by the WHO real-time RT-PCR were used to infer viral load. Concentrations of virus dilutions were estimated using standard curves generated with plasmids pFluA and pFluB from this study (see Supplementary Material).

CI, confidence intervals; FluA, influenza A; FluB, influenza B; LoD, limit of detection; na, not applicable.