Hepatitis C Diagnosis | MIMS Malaysia

Hepatitis%20c Diagnosis

Diagnosis

Important Points in the Clinical History of Patients with Suspected Viral Hepatitis

Serological Tests

Anti-hepatitis C virus (anti-HCV) antibodies are the first-line diagnostic test and are determined via enzyme immunoassay in plasma or serum
- HCV RNA (or HCV core antigen) should be determined to identify viremia or current HCV infection in patients with detected anti-HCV antibodies
Acute hepatitis C can be reliably diagnosed if recent seroconversion to anti-HCV antibodies (ie a prior negative HCV antibody test becomes positive) can be documented; however, antibody tests often do not become positive until 3 months after infection
- If the clinical suspicion is high, the patient should be tested for HCV RNA (or HCV core antigen) to establish the diagnosis
Chronic hepatitis C is continued HCV infection of ≥6 months after acquiring the disease and is diagnosed based on the presence of both anti-HCV antibodies and HCV RNA (or HCV core antigen)
HCV RNA quantitative testing to determine baseline viral load is recommended before starting antiviral therapy
- End of therapy is indicated by undetectable HCV RNA on a sensitive assay (≤15 IU/mL) 12 and 24 weeks after therapy
- Recommended test for assessment of HCV recurrence
Undetectable HCV core antigen can be an alternative endpoint of therapy in patients with detectable HCV core antigen before therapy

HCV genotype, including subtyping of genotype 1a/1b, should be determined, if possible (if a non-pangenotypic regimen will be prescribed), in all HCV-infected persons prior to treatment to determine type and duration of therapy and chances of response; predominant genotypes in Asia are:
- Genotypes 1b and 2: East Asia (China, Taiwan, South Korea, Japan)
- Genotype 3: South Asia (India and Pakistan)
  - Genotype 3 is considered difficult to treat and is associated with a poor prognosis
- Genotypes 1 and 6: Southeast Asia (Vietnam, Cambodia, Laos, Indonesia, Myanmar, Malaysia, Philippines, Thailand)

Liver biopsy may be done if it is thought that the results will influence clinical decision, but biopsy is not mandatory to start therapy
- Liver biopsy may be obtained to provide prognostic information

Depending on local health services, the following groups should be tested for chronic HCV infection:
- Persons who have in the recent or remote past used illicit IV/intranasal drugs, men who have sex with men (MSM)
- Persons with conditions associated with high prevalence of HCV infection:
  - Positive human immunodeficiency virus (HIV), sexually active individuals taking pre-exposure prophylaxis for HIV, hemophiliacs who received clotting factor prior to 1987, history of hemodialysis, persons who received blood/blood products or organ transplants prior to July 1992, children born to HCV-infected mothers, healthcare workers after needle stick injury or mucosal exposure to HCV-positive blood, current sexual partners of HCV-infected persons, incarcerated individuals

Tests to Rule Out Other Viral Hepatitis

Hepatitis A: Anti-hepatitis A virus (anti-HAV) IgM; nucleic acid amplification test (NAAT) for HAV RNA may be considered
Hepatitis B: Hepatitis B surface antigen (HBsAg), hepatitis B core antibody (anti-HBc), hepatitis B e antigen (HBeAg)
Hepatitis D: Anti-hepatitis D virus (anti-HDV) antibody, HDV RNA test
Hepatitis E: IgM anti-HEV, IgG anti-HEV in combination with HEV RNA; NAAT for HEV RNA may be considered
Please see Hepatitis A & E and Hepatitis B disease management charts for further information

Other Recommended Lab Tests in Patients Suspected of Viral Hepatitis

Liver function tests (LFTs)
- Aspartate aminotransferase (AST) and alanine aminotransferase (ALT)
- Serum bilirubin, alkaline phosphatase (ALP)
Prothrombin time (PT), international normalized ratio (INR), renal function tests, complete blood count (CBC) with platelets
Noninvasive tests such as the aminotransferase/platelet ratio index (APRI) or fibrosis-4 (FIB-4) must be used to assess the degree of hepatic fibrosis when resources are limited prior to initiating HCV therapy
- Transient elastography may be an option for patients with contraindications to or refusing liver biopsy
Ultrasound of the liver helps identify hepatocellular carcinoma (HCC) and subclinical ascites

Consequences of HCV Infection

55-85% of patients who acquire acute hepatitis C will remain HCV infected
- 5-20% of these patients may develop cirrhosis over the next 20-25 years
- HCV-related cirrhosis is associated with risk of developing end-stage liver disease (30% risk over 10 years) as well as HCC
In patients with persistent infection, the evolution to cirrhosis is the primary concern
- Usually occurs ≥20 years after initial infection and occurs more often in patients at older ages (especially men), those who drink >50 g of alcohol/day, those who are obese or have substantial hepatic steatosis and in those with HIV infection

Antiviral therapy is currently widely accepted for the following hepatitis C patient groups:

≥18 years of age
Elevated serum ALT levels
Liver biopsy showing chronic hepatitis with significant fibrosis or cirrhosis (stage F1 or above)
HCV genotype 2 or 3 regardless of stage
Compensated liver disease
Acceptable hematological and biochemical indices
Willing to be treated and conform to patient requirements

Therapy should be individualized in patients with any of the following:

Failed prior treatment of either Interferon given alone or in combination with Ribavirin or Peginterferon given alone
Current PWID or alcoholic but willing to participate in substance abuse program or alcohol support program
Acute hepatitis C
Coinfected with HIV
<18 years of age
Chronic renal disease
Known hypersensitivity to drugs used to treat HCV
Decompensated cirrhosis
Liver transplant recipient

Therapy is contraindicated in patients with any of the following¹:

¹Patients have detectable HCV RNA

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