New One-Step Algorithm for Hepatitis C Diagnosis

November 2024
Ampath | ampath.co.za

Background

• Hepatitis C virus (HCV) becomes chronic in up to 80% of infected individuals
• Chronic infection increases the risk of:
  • Decompensated cirrhosis
  • Hepatocellular carcinoma

✅ Good News: Treatment Works

• New direct-acting antivirals (DAAs) are highly effective
• Up to 99% cure rate with a 12-week course
• Pan-genotypic DAAs eliminate the need for genotype testing before starting treatment

Why Change the Diagnostic Approach?

• Only 20% of infected individuals are aware of their status
• Just 15% have received treatment
• WHO targets by 2030:
  • Treat 80% of eligible HCV cases
  • Reduce HCV incidence by 90%
  • Reduce HCV-related deaths by 65%

High-Risk Groups to Screen

• People who inject drugs (PWID)
• Men who have sex with men (MSM)
• Individuals who received blood products before 1992
• Patients exposed to unsafe injections or poor infection control

Lab Tests for HCV Diagnosis

✅ 1. HCV Antibody Test

• Mnemonic: HEPC
• Detects exposure to HCV
• A negative result excludes HCV (unless very recent exposure)
• A positive result requires confirmation with a viral detection test
• Not suitable for detecting reinfection after treatment

✅ 2. HCV Immunoblot (Western Blot)

• Mnemonic: HEPCWB
• Used in low prevalence settings where false positives are more likely
• Helps confirm or exclude low-level positive antibody results

✅ 3. HCV PCR / Viral Load

• Mnemonic: HEPCPCR or HCVVL
• Gold standard for confirming active infection
• Also used to confirm sustained virological response (SVR) after treatment
• Performed in centralised molecular labs

✅ 4. HCV Core Antigen Test (New!)

• Mnemonic: HEPCAG
• Surrogate marker for active HCV infection
• Detects viral replication at >3000 IU/mL
• More cost-effective and accessible than PCR
• Uses same specimen as the antibody test
• Suitable for high-throughput, decentralised testing

✅ 5. HCV Genotyping

• Mnemonic: HCVGEN
• No longer routinely required before treatment, thanks to pan-genotypic DAA therapy
• May still be helpful in select cases

New Ampath Diagnostic Algorithm for HCV

Ampath has introduced a simplified, one-step algorithm to confirm HCV infection and guide treatment:

🔄 Diagnostic Workflow:

1. HCV Antibody EIA Positive?
   • ✅ Yes → Proceed with HCV Core Antigen Test
     • Positive?
       → HCV infection confirmed → Assess for DAA treatment
     • Negative?
       → Likely past/resolved infection or false positive
       → Consider HCV PCR if clinical suspicion remains
2. HCV Antibody EIA Low Positive?
   • Perform HCV Immunoblot
     • If confirmed positive → Add HCV Core Antigen or PCR to check viraemia

❗ Note: Supplemental tests are not automatically performed for cash-paying patients.

📌 Need assistance or more info?
Contact your Ampath virology or hepatology specialist.