TABLE 3.

HCV RNA quantitative lower limit detection rates using the COBAS HCV TM-ASR assay^a

Expected virus level (HCV RNA IU/ml)b	Observed avg HCV RNA IU/mlc	SDd	% CV	% Observed vs Expected	No. of quantitative resultse	No. of valid resultsf	% Results quantitative
100	38.9	22.1	57	38.9	65	80	81.3
50	23.0	17.1	74	45.9	35	80	43.8
35	20.9	10.6	51	59.7	26	79	32.9
25	17.9	7.0	39	71.6	9	79	11.4
10	13.0	3.7	28	130.0	2	80	2.5
0	0.0				0	75	0.0

^aA panel consisting of a diluted HCV specimen of genotype 1a and an HCV RNA-negative member containing predefined concentration levels at 0, 10, 25, 35, 50, and 100 IU/ml was processed in replicate across multiple runs. Five runs were performed using the Qiagen BioRobot 9604 and QiaAmp virus kit for HCV RNA extraction and COBAS HCV TaqMan ASR reagents and the COBAS TaqMan Analyzer for RNA amplification and detection. HCV RNA-positive members were processed in replicates of 16 on each run, and the HCV RNA-negative member was processed in replicates of 15 on each run.

^bVirus level was predefined by Roche Molecular Systems.

^cAverage HCV RNA level was calculated from any quantitative result for a given virus level.

^dStandard deviation.

^eQuantitative results were defined as any result with an HCV RNA concentration calculated. Results were not included if they were “<10 IU/ml,” “invalid,” or “target not detected.”

^fA valid result was defined as any result with a valid quantitation standard elbow value result and not called “invalid” by the COBAS TaqMan Analyzer and TaqLink software.