Positive (+) and Negative (–) Viral Hepatitis B and Viral Hepatitis C Profiles: Practical Interpretation with WHO & CDC 2024–25 Updates (Viral Hepatitis Profiles)

Below is a self-contained, exam-ready deep dive on reading positive (+) and negative (–) viral-hepatitis profiles. I keep the practical “what you do at the bedside” front-and-center while weaving in the newest WHO (2024 HBV, 2024 HCV), CDC (2025 HBV) and AASLD recommendations.

1 Why the marker is positive or negative matters

Marker class	“Positive” means …	“Negative” means …	Caveats you must always rule out
Presence of virus (HBsAg, HCV RNA/Ag)	Detectable virions or viral proteins in blood	None detected at the assay’s limit	• Window periods (HBV “core-window”, very early acute HCV) • Low-level occult infection (HBsAg–/HBV-DNA+)
Immune memory (anti-HBc, anti-HBs, anti-HCV)	B-cell response has occurred	No measurable antibodies	• Profound immunosuppression (chemo, anti-CD20) • Age < 18 mo (maternal antibody interference)
Phase/infectivity (HBeAg, HBV-DNA titer)	Active transcription / high infectivity	“Pre-core mutant” or inactive carrier if negative	• Pre-core/ basal-core-promoter mutants generate high DNA but are HBeAg-negative

2 Hepatitis B: interpretation grid

HBsAg	total anti-HBc	IgM anti-HBc	anti-HBs	Typical interpretation	Key follow-ups
–	–	–	–	Susceptible	Vaccinate
–	–	–	+	Immune – vaccine	None
–	+	–	+	Immune – past infection	Check fibrosis only if past ALT peaks
+	+	+	–	Acute infection	HBV-DNA, ALT q4 wk; treat if fulminant
+	+	–	–	Chronic infection	Stage (ALT, elastography), treat per WHO 2024 simplified criteria who.int
–	+	–	–	Isolated anti-HBc – four possibilities	Reflex HBV-DNA ± repeat anti-HBs in 6 wk

2024 WHO shift: Treat earlier (HBV-DNA ≥ 2 000 IU/mL or ALT > 2×ULN) even when fibrosis is mild to cut lifelong HCC risk. who.int

Pitfalls of “negative” HBV markers

False-negative HBsAg in the core window (just after HBsAg disappears, before anti-HBs appears) – total anti-HBc plugs the gap.
Occult HBV (HBsAg– / HBV-DNA+) in HIV, dialysis, solid-organ transplant → screen with HBV-DNA when risk is high.
Vaccination failure: anti-HBs < 10 mIU/mL after full series warrants revaccination or high-dose schedules (CDC 2025) cdc.gov.

3 Hepatitis C: two-step reflex algorithm (WHO 2024)

Screen – anti-HCV EIA or rapid test.
If (+) – reflex HCV RNA (or core-Ag) on the same sample. Skipping the reflex step leaves up to 30 % of patients lost to follow-up. iris.who.int

Anti-HCV	HCV RNA	Interpretation	Action
–	–	Never exposed (or < 3 wk incubation)	No further testing unless new exposure
+	–	Cleared (spontaneous or treated) or false-positive	If high suspicion, repeat RNA in 3 mo
+	+	Current infection (acute or chronic)	Stage liver (APRI/FIB-4); start pangenotypic DAA
–	+	Early acute infection or severe immunosuppression	Repeat Ab in 4–6 wk; treat now if acute icteric

Key nuance: Acute vs chronic HCV no longer changes the decision to start DAA—the earlier you treat, the higher the sustained virologic response.

When a “negative” test misleads

Anti-HCV-negative, RNA-positive – up to 30 % in bone-marrow transplant or rituximab recipients.
RNA false-negative on ultralow-viremia < 15 IU/mL – repeat in 4 wks if suspicion persists or use core-Ag assay (LOD ~ 500 IU/mL). who.int

4 Applying positives & negatives at the bedside

Patient with unexplained transaminase flare: order viral-hepatitis panel (HBsAg, anti-HBs, total anti-HBc, IgM anti-HBc, anti-HCV) + ALT/AST.
HBsAg+ → add HBeAg, HBV-DNA, platelets, and elastography.
Anti-HCV+ → reflex RNA; if (+) stage liver and treat.
Any chronic infection → test HIV, screen family/sexual partners, vaccinate against HAV/HBV as appropriate.

5 Cheat-sheet of “must-remember” positives and negatives

Scenario	Why it’s high-stakes	Don’t forget
HBeAg+ & HBV-DNA > 2 000 IU/mL	Highly infectious – test household; consider early therapy in pregnancy to cut MTCT risk	Tenofovir 3rd-trimester prophylaxis per WHO 2024
Isolated anti-HBc before rituximab	5–10 % risk of HBV reactivation	Pre-emptive antiviral (entecavir/ tenofovir)
Anti-HCV+, RNA–	Up to one-third are already cured – avoid unnecessary DAA	Check for previous DAA, document SVR
Anti-HCV–, ALT spike, risk factors	Could be very early acute HCV	Repeat anti-HCV + RNA in 3 wk
HBsAg–, anti-HBs > 10 mIU/mL	Immune – can donate blood, no HBV prophylaxis needed	Re-check titer only in dialysis, immunocomp.

Key take-home

Positive and negative are never absolute—they are snapshots in time limited by assay sensitivity, host immunity, and the natural history of the virus. Use the combination pattern, not single markers, chase every discordance, and lean on updated WHO/CDC algorithms to decide who needs vaccination, surveillance, or immediate antiviral therapy.