TABLE 1.

Intra-assay precision of testing with 20 replicates of calibrators, controls, and human sera

Sample	HBsAg concn (IU/ml)a	Chemilumi-nescence signal (counts)	Mean s/co ratio	SD	CV (%)
Negative calibrator	0	236		14	6.1
Positive calibrator	0.5	3,471		43	1.2
Negative control	0	257	0.56	0.04	6.3
Positive control	0.2	1,318	2.88	0.04	1.2
HBsAg-negative serum		263	0.49	0.03	6.9
HBsAg-negative serum spiked with HBsAg	0.05	592	1.1	0.03	2.9
HBsAg-positive serum	ND	5,089	9.44	0.16	1.7

^aND, not determined.