Fluctuation of HCV viral load before seroconversion in a healthy volunteer blood donor.

Background: Newly implemented NAT has been shown to be able to effectively identify HCV-positive blood donated during the preseroconversion period.

Study Design And Methods: EDTA-plasma pools of 24 donations were tested using an HIV-1/HCV multiplex NAT under an FDA-approved IND application. Samples in a positive pool were retested individually. Positive samples were further tested by two discriminatory assays to determine specific viral reactivity. Upon obtaining informed consent, seronegative donors with positive NAT results were enrolled into a follow-up study for risk factor analysis and laboratory testing.

Results: A donation by a 29 year old female was identified as HCV NAT-positive with negative serology and an elevated ALT. Her two previous donations, 5 and 12 months earlier, were both seronegative and with normal ALT. Her husband tested positive for HCV RNA. The donor remained seronegative for at least 36 days. The index donation had a viral RNA concentration of >500,000 copies per mL while the first seropositive sample was NAT-negative. Laboratory data on serial follow-up samples showed 100- to 1,000-fold fluctuations in viral load during a period of 48 days prior to seroconversion.

Conclusions: This case suggests that, at least in some newly infected individuals, the HCV viral load can fluctuate dramatically prior to seroconversion, and that NAT, even on individual samples, will not totally prevent HCV transmission.