Table 2. Intra-assay (CVi%) and inter-assay (CVo%) variation of the duplex real-time PCR assay.

Variation	Concentration of reference plasmid (copies/µl)	E. chaffeensis 120kD		A. phagocytophilumankA
		Ct	CV%	Ct	CV%
Intra-assay	1×106	17.2	0.2	18.2	0.9
(CVO%)	1×105	20.3	0.9	20.5	0.8
	1×104	23.9	1.3	24.3	0.1
	1×103	27.6	0.7	28.1	1
	1×102	31.6	0.6	31.7	1.1
Inter-assay	1×106	17.5	3.5	18.9	2.6
(CVI%)	1×105	20.4	2.9	21.9	3.1
	1×104	24.2	3.2	25.2	2.7
	1×103	27.7	3.3	28.3	3.7
	1×102	31.8	2	32.6	2