How do I interpret hepatitis B virus (HBV) and hepatitis C virus (HCV) serology panels?

How to Read Hepatitis Titer Results

Interpreting hepatitis serology requires systematic analysis of specific viral markers to determine infection status—whether never infected, acutely infected, chronically infected, resolved with natural immunity, or vaccinated—with each pattern having distinct clinical implications for management and prognosis.

Hepatitis B Serology: Core Markers and Their Meaning

HBsAg (Hepatitis B Surface Antigen)

• HBsAg positive indicates active HBV infection (acute or chronic) and confirms the person is infectious 1
• HBsAg appears approximately 30 days after exposure (range: 6-60 days) and is the first serological marker detectable in acute infection 1
• Persistence of HBsAg for >6 months defines chronic HBV infection 1, 2
• HBsAg negative rules out active infection (except rare occult HBV) 2

Anti-HBs (Antibody to HBsAg)

• Anti-HBs ≥10 mIU/mL indicates protective immunity against HBV 2, 3
• Anti-HBs appears after HBsAg clearance in resolved infection or after successful vaccination 1, 2
• Critical distinction: Anti-HBs alone (without anti-HBc) indicates vaccine-induced immunity, while anti-HBs plus anti-HBc indicates natural immunity from resolved infection 2, 3

Anti-HBc (Antibody to Hepatitis B Core Antigen)

• Total anti-HBc appears at symptom onset in acute infection and persists for life in the majority of persons 1
• Anti-HBc is never produced by vaccination—its presence always indicates natural infection (past or current) 2, 3
• IgM anti-HBc indicates acute or recently acquired infection, persisting up to 6 months after acute infection 1, 2
• Use IgM anti-HBc testing only in patients with clinical evidence of acute hepatitis or epidemiologic link to HBV, as false positives occur in asymptomatic persons 1

HBeAg and Anti-HBe

• HBeAg positive correlates with high viral replication (HBV DNA 10⁶-10¹⁰ IU/mL) and increased infectivity 1
• Anti-HBe positive generally indicates decreased viral replication (HBV DNA 0-10⁵ IU/mL) 1
• These markers are essential for determining the phase of chronic HBV infection and guiding treatment decisions 2

HBV DNA

• HBV DNA provides direct quantitative measurement of viral replication and is essential for diagnosis, treatment decisions, and monitoring 2
• Highly sensitive nucleic acid tests can detect HBV DNA 10-20 days before HBsAg appears 1, 2

Hepatitis B: Common Serological Patterns

Never Infected / Susceptible

• HBsAg: Negative
• Anti-HBs: Negative
• Anti-HBc: Negative 2

Vaccine-Induced Immunity

• HBsAg: Negative
• Anti-HBs: Positive (≥10 mIU/mL)
• Anti-HBc: Negative 2, 3
• This is the only pattern where anti-HBs is positive without anti-HBc 3

Acute HBV Infection

• HBsAg: Positive
• Anti-HBs: Negative
• IgM anti-HBc: Positive (key marker)
• HBV DNA: Positive 2

Chronic HBV Infection

• HBsAg: Positive (>6 months)
• Anti-HBs: Negative
• Total anti-HBc: Positive
• IgM anti-HBc: Negative (or low-level positive during flares)
• HBV DNA: Typically positive 1, 2

Resolved Infection (Natural Immunity)

• HBsAg: Negative
• Anti-HBs: Positive (≥10 mIU/mL)
• Total anti-HBc: Positive
• HBV DNA: Negative 2
• This pattern distinguishes natural immunity from vaccine-induced immunity 2, 3

Isolated Anti-HBc Positive

• HBsAg: Negative
• Anti-HBs: Negative
• Total anti-HBc: Positive only 1, 2
• This pattern represents: (1) resolved infection with waning anti-HBs (most common in high-prevalence populations), (2) occult chronic infection with undetectable HBsAg (HBV DNA detectable in <5%), or (3) false-positive result 1, 2
• Consider HBV DNA testing in immunocompromised patients or those from high-prevalence regions to detect occult hepatitis B 2

Phases of Chronic Hepatitis B Infection

Understanding the phase is critical because management differs dramatically:

Phase 1: HBeAg-Positive Chronic HBV Infection (formerly "Immune Tolerant")

• HBeAg: Positive
• Anti-HBe: Negative
• HBV DNA: Very high (≥10,000 IU/mL)
• ALT: Persistently normal
• Liver inflammation: Minimal or absent 2
• Typically seen in perinatal infection; low risk of progression (1% cirrhosis, 1.7% HCC over 10 years) 2

Phase 2: HBeAg-Positive Chronic Hepatitis B

• HBeAg: Positive
• Anti-HBe: Negative
• HBV DNA: High (≥20,000 IU/mL)
• ALT: Elevated
• Liver inflammation: Moderate to severe 2
• Treatment consideration required 2

Phase 3: HBeAg-Negative Chronic HBV Infection (Inactive Carrier)

• HBeAg: Negative
• Anti-HBe: Positive
• HBV DNA: Low (<2,000 IU/mL)
• ALT: Persistently normal
• Liver inflammation: Minimal 2
• Favorable long-term prognosis with very low risk of cirrhosis or HCC, but approximately 20% may reactivate 2
• Requires lifelong monitoring with ALT every 6 months and periodic HBV DNA measurement 2

Phase 4: HBeAg-Negative Chronic Hepatitis B

• HBeAg: Negative
• Anti-HBe: Positive
• HBV DNA: ≥2,000 IU/mL (moderate to high)
• ALT: Elevated or fluctuating
• Liver inflammation: Moderate to severe 2
• High risk of cirrhosis and HCC; associated with viral mutants (basal-core-promoter or precore mutations) 2
• Treatment recommended if HBV DNA ≥2,000 IU/mL with elevated ALT 2

Phase 5: HBsAg-Negative Resolved Infection

• HBsAg: Negative
• Anti-HBc: Positive (± anti-HBs)
• HBV DNA: Undetectable
• ALT: Normal 2
• Represents functional cure, though cccDNA may persist in liver allowing reactivation under immunosuppression 2

Hepatitis C Serology

Anti-HCV (Antibody to HCV)

• Anti-HCV positive indicates past or current HCV infection 1
• Anti-HCV antibodies appear weeks to months after infection and do not indicate immunity or viral clearance 4
• Critical limitation: 10% of chronic HCV infections with liver disease remain seronegative despite circulating HCV RNA 5

HCV RNA

• HCV RNA positive indicates active, current HCV infection 1
• HCV RNA is the definitive test to distinguish active infection from resolved infection 1
• Interpretation algorithm: If anti-HCV positive, order HCV RNA to determine if infection is active (RNA positive) or resolved (RNA negative) 4, 6

Hepatitis A Serology

Total Anti-HAV (IgG Anti-HAV)

• Total anti-HAV positive indicates past HAV infection or vaccination and confers lifelong immunity 1, 2
• This is the definitive test to confirm immunity to hepatitis A 2

IgM Anti-HAV

• IgM anti-HAV positive indicates acute HAV infection 1, 4
• IgM anti-HAV is the diagnostic marker for acute hepatitis A 7

Critical Pitfalls to Avoid

Hepatitis B Pitfalls

• Never rely on a single ALT or HBV DNA measurement to determine treatment, especially in HBeAg-negative disease where levels fluctuate 2
• Do not assume HBeAg-negative/anti-HBe-positive patients are inactive carriers without confirming HBV DNA <2,000 IU/mL and persistently normal ALT over time 2
• Transient HBsAg positivity can occur up to 18 days after hepatitis B vaccination and is clinically insignificant 1, 2, 3
• IgM anti-HBc can persist at low levels in chronic infection and can be positive during exacerbations, potentially leading to misdiagnosis as acute infection 1, 2
• Isolated anti-HBc requires further workup: Consider HBV DNA testing, especially in immunocompromised patients, to rule out occult hepatitis B 1, 2
• Serial monitoring is essential: A single set of results is insufficient to assign a phase of chronic HBV infection reliably 2

Hepatitis C Pitfalls

• Anti-HCV positive does not distinguish active from resolved infection—always order HCV RNA for confirmation 4, 6, 5
• Delayed antibody appearance: Anti-HCV may not be detectable for weeks to months after acute infection 5
• Seronegative chronic HCV exists: Up to 10% of chronic HCV infections remain anti-HCV negative despite active viral replication 5

Practical Testing Algorithm

For Suspected Acute Hepatitis B

1. Order: HBsAg, total anti-HBc, IgM anti-HBc, anti-HBs 1, 2
2. If HBsAg positive and IgM anti-HBc positive → Acute HBV infection 2
3. Repeat HBsAg, anti-HBs, and total anti-HBc at 6 months to confirm resolution 2

For Chronic HBV Infection Evaluation

1. Confirm HBsAg positive >6 months 1, 2
2. Order: HBeAg, anti-HBe, HBV DNA quantitative, ALT 2
3. Use these results to determine phase (see above) and guide treatment decisions 2
4. Never skip HBeAg/anti-HBe testing—these are essential for phase determination and prognosis 2

For HBV Immunity Assessment

1. Order: HBsAg, anti-HBs, total anti-HBc 2, 3
2. If anti-HBs ≥10 mIU/mL and anti-HBc negative → Vaccine-induced immunity 3
3. If anti-HBs ≥10 mIU/mL and anti-HBc positive → Natural immunity from resolved infection 2, 3

For Hepatitis C Evaluation

1. Order: Anti-HCV 1
2. If anti-HCV positive → Order HCV RNA to distinguish active (RNA positive) from resolved (RNA negative) infection 4, 6