Hepatitis C is the Cause of Chronic Hepatitis in This Patient
In a patient who received a blood transfusion over 12 years ago and now presents with chronic hepatitis signs, hepatitis C virus (HCV) is the causative agent, not hepatitis B. The positive hepatitis B antibodies indicate resolved past HBV infection or vaccination-induced immunity, not active chronic hepatitis B disease 1, 2.
Serologic Interpretation: Why Not Hepatitis B
Positive anti-HBs (hepatitis B surface antibody) with negative HBsAg indicates immunity to hepatitis B from either resolved past infection or vaccination—it definitively rules out chronic hepatitis B infection 1, 2.
Chronic hepatitis B requires persistent HBsAg positivity for >6 months; the absence of HBsAg excludes chronic HBV as the cause of this patient's liver disease 1, 3.
The serologic pattern described (HBsAg negative, anti-HBs positive) represents past HBV infection with recovery or vaccine immunity, not active chronic infection 2.
Why Hepatitis C is the Answer
Historical Transfusion Risk
Blood transfusions performed before 1992 carried extremely high risk for HCV transmission because routine donor screening was not yet available 1, 2.
Post-transfusion hepatitis C was the most common cause of transfusion-transmitted viral hepatitis in the pre-screening era 1.
Mandatory HCV screening of blood donations only began in 1990, meaning this patient's transfusion 12 years ago (if before 1992) occurred during the high-risk period 2.
Natural History Supporting HCV
Approximately 77% of individuals who acquire HCV after transfusion develop chronic infection, compared to only 6-10% chronicity rate for adult-acquired HBV 1.
About 50% of patients with transfusion-associated hepatitis C develop biochemical evidence of chronic liver disease within 12 months 4, 2.
Within the first 5 years after transfusion-associated HCV infection, ≥40% develop chronic active hepatitis and 10-20% have cirrhosis on biopsy, often with minimal symptoms 4, 2.
Only approximately 10% of HCV-infected persons experience acute symptomatic illness; the majority have subclinical infection that evolves to chronic hepatitis 1.
Clinical Reasoning Algorithm
Step 1: Exclude Active Hepatitis B
- Verify HBsAg is negative → rules out chronic HBV 1, 2
- Confirm anti-HBs is positive → indicates HBV immunity, not disease 1, 2
Step 2: Confirm Hepatitis C
- Perform anti-HCV antibody testing; a positive result supports chronic HCV infection in this transfusion context 1, 2
- Confirm active infection with quantitative HCV RNA PCR; detectable RNA indicates ongoing viral replication 1, 2
Step 3: Assess Disease Severity
- Measure liver transaminases (ALT/AST), which are typically elevated in chronic active HCV 1
- Determine HCV genotype (most commonly genotype 1b in transfusion-associated cases) to guide therapy 1
Critical Pitfalls to Avoid
Do not confuse anti-HBs positivity with active hepatitis B infection—this is a protective antibody, not a marker of disease 1, 2.
The majority of patients with chronic hepatitis C remain asymptomatic for years, even when cirrhosis is present, leading to frequent under-recognition 2.
Anti-HCV antibody positivity alone does not distinguish between resolved and chronic HCV infection; HCV RNA testing is mandatory to confirm active chronic infection 2.
Long-Term Prognosis
In cohorts followed for >20 years after transfusion, approximately 51% developed cirrhosis and 5% developed hepatocellular carcinoma 1.
The median interval from HCV acquisition to cirrhosis is roughly 30 years, underscoring the need for long-term surveillance 1.
Approximately 32% of those with chronic HCV progress to cirrhosis within a mean follow-up of 7.5 years 1.