Table 2.

Agreement between the 200 and 500 µL protocols of the Cobas 5800 system^*

Variable		Roche 500 µL protocol
		HBV†			HBV‡			HCV†			HCV‡
		Positive	Negative		Positive	Negative		Positive	Negative		Positive	Negative
Roche 200 µL protocol	Positive	88	2		78	0		100	1		99	0
	Negative	13	57		6	76		0	75		1	76
Positive agreement (%)		87.1 (79.0–93.0)			92.9 (85.1–97.3)			100.0 (96.4–100.0)			99.0 (94.6–100.0)
Negative agreement (%)		96.6 (88.3–99.6)			100.0 (95.3–100.0)			98.7 (92.9–100.0)			100.0 (95.3–100.0)
Total agreement (%)		90.6 (85.0–94.7)			96.3 (92.0–98.6)			99.4 (96.88–99.99)			99.4 (96.9–100.0)
Kappa value		0.8 (0.7–0.9)			0.9 (0.9–1.0)			1.0 (1.0–1.0)			1.0 (1.0–1.0)

*Agreement rates are expressed as the 95% confidence interval.

^†The ‘<titer min’ results of both the 200 and 500 µL protocols were designated as positive.

^‡The ‘<titer min’ results of both the 200 and 500 µL protocols were designated as negative. The results of HBV and HCV tests are displayed in three formats: numerical value (IU/mL) (positive), ‘<titer min’ (less than titer minimum), and ‘target not detected’ (negative). According to the manufacturer’s instructions, the titer minimum was 25 IU/mL for the 200 µL protocol and 10 IU/mL for the 500 µL protocol for the HBV assay. For the HCV assay, the titer minimum was 40 IU/mL for the 200 µL protocol and 15 IU/mL for the 500 µL protocol.

Abbreviations: HBV, hepatitis B virus; HCV, hepatitis C virus.