Chiron RIBA HCV 3.0 SIA

CHIRON^® RIBA 3.0, SIA

HCV Genome and Recombinant Proteins

CHIRON^® RIBA^® 3.0 SIA

Prevalence: Reactivity in Volunteer Random Blood Donors (Low Risk)

A total of 3004 sequential, previously unscreened, random blood donations were collected prospectively and tested at three blood centers participating as clinical sites. Table 3 summarizes the results. Of these 3004 donors, 5 were positive by both assays and 2955 were negative by both assays. Twenty-nine specimens were indeterminate by CHIRON RIBA HCV 3.0 SIA only and 9 were indeterminate by CHIRON RIBA HCV 2.0 SIA only. Assuming that those indeterminate results represent uninfected individuals, the specificity of CHIRON RIBA HCV 2.0 SIA is 99.5% (2984/2999) and the specificity of CHIRON RIBA HCV 3.0 SIA is 98.8% (2964/2999). (Specificity was calculated as follows: TN/TN + FP, where TN = true negatives, that is, the number of specimens negative by CHIRON RIBA SIA; and FP = false positives, that is, the number of specimens indeterminate by CHIRON RIBA SIA.)

Table: CHIRON RIBA HCV 2.0 SIA and CHIRON RIBA HCV 3.0 SIA Testing Results for Volunteer Blood Donors at Three Blood Centers (Low Risk)

CHIRON^® RIBA^® 3.0 SIA

Sensitivity in Seroconversion Panels

A total of 86 seroconversion panels from individuals with documented seroconversion to antibodies to HCV and clinical documentation of NANBH were tested. Subjects were categorized as acute if two sequential serum specimens had SGPT/ALT levels greater than 44 IU/L and 90 IU/L, respectively, and the SGPT/ALT level returned to normal within six months. Subjects whose SGPT/ALT level remained greater than two times the upper limit of normal for longer than six months were categorized as having chronic NANBH. All subjects diagnosed as having NANBH were serologically negative for hepatitis A and hepatitis B. The table below summarizes the CHIRON RIBA HCV 2.0 SIA and CHIRON RIBA HCV 3.0 SIA results from these panels.

* The term "sensitivity" refers to any reactivity (indeterminate or positive).

In 52 of the 86 panels (60%), CHIRON RIBA HCV 3.0 SIA showed greater sensitivity or earlier positivity than CHIRON RIBA HCV 2.0 SIA. In 21 panels (24%), both assays detected anti-HCV (i.e., indeterminate or positive) on the same blood draw, but CHIRON RIBA HCV 3.0 SIA became positive earlier than CHIRON RIBA HCV 2.0 SIA. In 31 panels (36%), CHIRON RIBA HCV 3.0 SIA detected anti-HCV (i.e., indeterminate or positive) earlier than CHIRON RIBA HCV 2.0 SIA, with a mean difference of 50 days (range 9 to 282 days) between detection by CHIRON RIBA HCV 2.0 SIA and CHIRON RIBA HCV 3.0 SIA. In no case was CHIRON RIBA HCV 3.0 SIA less sensitive than CHIRON RIBA HCV 2.0 SIA.