TABLE 4.

Results of multicenter reproducibility study

Sample no.	RMS			UNM			JHU			Combined resultsa
	Calculated RNA concn (no. of copies/ml)		CV (%)	Calculated RNA concn (no. of copies/ml)		CV (%)	Calculated RNA concn (no. of copies/ml)		CV (%)	Calculated RNA concn (no. of copies/ml)		CV (%)
	Day 1	Day 2		Day 1	Day 2		Day 1	Day 2		Mean	SD
1	66	28	57	55	50	7	79	14	99	49	31	64
2	9,182	4,924	43	5,052	5,243	3	6,034	3,994	29	5,738	1,929	34
3	111	47	57	67	126	43	87	67	18	84	36	43
4	12,010	7,647	31	9,785	9,000	6	10,097	6,535	30	9,179	2,322	25
5	588	823	24	686	608	9	1,114	882	16	784	212	27
6	18,522	14,584	17	8,190	8,886	6	12,237	9,921	15	12,057	4,308	36
7	4,492	3,384	20	3,241	3,652	8	4,792	2,484	45	3,674	1,059	29
8	15,189	10,763	24	9,513	12,600	20	8,637	5,295	34	10,333	3,575	35
9	923	651	24	654	525	15	1,059	451	57	711	277	39
Median CV			24			8			30			35

^aThe mean was calculated by averaging the six individual determinations for each test sample. The standard deviations and CVs among laboratories were determined by performing a nested analysis of variance similar to that described in guideline EP5T of the National Committee for Clinical Laboratory Standards (19).