A 28-year-old blood donor tests negative for anti-HCV antibody but the blood bank's HCV RNA NAT is positive. The most accurate interpretation is:

• A False-positive NAT result; antibody test is definitive
• B Resolved HCV infection with persistent HCV RNA
• C Occult HCV infection in an immunocompromised host
• D Window-period HCV infection with viremia preceding seroconversion ✓

Explanation

Anti-HCV antibody typically becomes detectable 8–12 weeks after infection (serological window period), while HCV RNA appears within 1–2 weeks of infection. An NAT-positive, antibody-negative result in a healthy donor is most consistent with acute window-period infection where viremia precedes seroconversion. This is why HCV NAT screening was introduced for blood banking — it effectively shortens the window period from ~70 days to approximately 7–10 days. Resolved infection would typically not have detectable RNA; occult HCV refers to low-level hepatic HCV RNA without serum RNA.

Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.

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Written and medically reviewed by the StethoPrep medical team.