Hepatitis C Virus - HCV

Diagnosis

Indications for Testing

  • New onset of jaundice, anorexia, or dark urine
  • Known exposure to hepatitis
  • Suspicion of chronic hepatitis (elevated liver enzymes)

Laboratory Testing

  • Testing recommendations for chronic hepatitis C (CDC)
  • Initial testing – rule out hepatitis A (HAV) or B (HBV) in acute presentation
    • Perform HAV antibody IgM, HBV core antibody IgM, HBV surface antigen, and HCV antibody testing
      • Positive HCV from hepatitis panel – perform HCV RNA PCR (quantitative or qualitative; quantitative generally preferred)
        • Documents baseline level of viremia
        • Quantitative or qualitative PCR test negative – infected but recovered or false-positive screen
          • Inform patient that they do not have active infection 
        • Quantitative or qualitative PCR test positive – currently infected (chronic HCV)
      • Coinfection with HBV – predicts poorer prognosis
  • Further testing once initial HCV testing is positive
    • Consider HIV testing – coinfection associated with poorer prognosis 
    • Perform HCV genotyping – guides selection of most appropriate antiviral regimen
      • Subtyping for 1a, 1b, and 6 may be useful
    • Consider interleukin 28 B (IL28B) and/or inosine triphosphatase (ITPA) typing in patients with HCV genotype 1
      • IL28B – predicts response to peginterferon (PEG-IFNα) and ribavirin (RBV) therapy for chronic genotype 1 HCV
      • ITPA – predicts response to PEG-IFNα/RBV therapy for chronic HCV-1 infection, aid in dose planning, and predicts risk of RBV treatment-related anemia
    • Liver biopsy
      • Consider if patient is HCV genotype 1
      • More advanced disease associated with lower response to therapy

Prognosis

  • HCV RNA PCR quantitative – viral load predicts likelihood of treatment response
    • Lower viral load at therapy initiation suggests better therapeutic response

Differential Diagnosis

Screening

  • Patients from high-risk populations (eg, IV-drug use, immigrant from endemic areas)  
    • CDC (2012), IDSA (2014), USPSTF (2013)  – screen at least once for all persons born between 1945-1965
      • Other persons should be screened for risk factors for HCV infection, and one-time testing should be performed for all persons with behaviors, exposures, and conditions associated with an increased risk of HCV infection
    • American Gastroenterological Association, National Gastroenterology Society (2009), National Hepatology Society (2003) – all recommend screening
      • Initial screening for HCV antibodies by CIA, EIA, ELISA
      • Followup testing required for positive result
    • For pregnant females, routine HCV screening is not recommended
    • Annual HCV testing for drug injection and HIV seropositive men who have unprotected sex with men (IDSA 2014)

Monitoring

  • HCV RNA PCR quantitative test – monitor effectiveness of treatment and perform when treatment is complete
    • Monthly until week 12 of treatment
    • Negative result confirms treatment success

Clinical Background

Hepatitis C is a virally mediated disease of the liver with a propensity to cause chronic infection leading to cirrhosis and an increased risk of hepatocellular carcinoma.

Epidemiology

  • Prevalence – 2% of U.S. population is infected  
    • >50% of new cases are caused by IV drug use
    • ~25,000 laboratory-confirmed chronic hepatitis C cases (National Notifiable Diseases Surveillance System, 2010)
  • Age – peaks in 30s-40s
  • Sex – M:F, equal

Organism

  • Single-stranded RNA virus; member of Flaviviridae family (genus Hepacivirus)
  • Six major genotypes with multiple subtypes (1a, 1b, 1c, etc)
    • Genotype is an important predictor of virologic response to HCV treatment
      • Type 1 is predominant genotype in U.S.
      • Types 2 and 3 are less aggressive and easier to treat

Genetics

  • Interleukin 28 B (IL28B) genotype

    IL28B Genotype Interpretation

    Genotypes

    Interpretation

    rs12979860 C/C

    Favorable

    • Two- to threefold greater rate of sustained virological response (SVR) following PEG-IFNα/RBV therapy
    • Threefold increase in natural clearance of HCV

    rs8099917 T/T

    Favorable                                                             

    • Higher rate of SVR following PEG-IFNα/RBV therapy
    • Increased natural clearance of HCV
    rs12979860 C/T
    rs12979860 T/T
    rs8099917 T/G
    rs8099917 G/G

    Not Favorable

    • Less likely to respond to treatment and achieve SVR

    One favorable and one not favorable SNP identified

    Indeterminate

    • Likelihood of SVR following PEG-IFNα/RBV therapy not well-defined
    Inosine triphosphatase (ITPA) genotype

    ITPA Genotype Interpretation

    Genotypes

    Interpretation

    rs1127354 A/A
    rs1127354 A/C
    rs7270101 C/C
    rs7270101 C/A

    Protective

    • Decreased ITPase activity
    • Protection against RBV treatment-related anemia in individuals with HCV
    rs1127354 C/C
    rs7270101 A/A

    Not Protective

    • Susceptible to RBV-induced hemolytic anemia

    One protective and one not protective SNP identified

    Indeterminate

    • Moderate decrease in ITPase activity
    • Decreased hemolytic side effects from RBV therapy

Risk Factors (from IDSA guidelines, 2014)

  • Risk behaviors
    • Injection-drug use (current or ever, including those who injected once)
    • Intranasal illicit drug use
  • Risk exposures
    • Long-term hemodialysis (ever)
    • Getting a tattoo in an unregulated setting
    • Healthcare, emergency medical, and public safety workers after needle sticks, sharps, or mucosal exposures to HCV-infected blood
    • Children born to HCV-infected women
    • Prior recipients of transfusions or organ transplants, including persons who
      • Were notified that they received blood from a donor who later tested positive for HCV infection
      • Received a transfusion of blood or blood components, or underwent an organ transplant before July 1992
      • Received clotting factor concentrates produced before 1987
      • Were ever incarcerated
  • Other medical conditions
    • HIV infection
    • Unexplained chronic liver disease and chronic hepatitis, including elevated alanine aminotransferase levels

Clinical Presentation

  • HCV typically asymptomatic in acute infection
    • Infection may be identified when patient has positive anti-HCV in a blood donor screen or has high alanine aminotransferase in blood chemistry testing for flu-like symptoms (10-20 times the upper limit of normal)
  • Chronic asymptomatic hepatitis may manifest with other systemic symptoms
    • Mixed cryoglobulinemia – systemic vasculitis involving skin, kidneys, nervous system
    • Sjögren syndrome – anti-SSA and SSB antibodies are usually absent or present in low levels
    • Lichen planus – violaceous papules on any skin site; oral most common
    • Porphyria cutanea tarda
    • Non-Hodgkin lymphoma – B-cell type most common
  • Chronic disease states occur in ~10-20% of patients
    • Cirrhosis (20%) and hepatocellular carcinoma (1-5%)
  • Pregnant females
    • Not transmitted to infant via breast feeding 
    • Pregnancy not contraindicated

Treatment

  • Genotypes 2 and 3 have more favorable prognosis and treatment response

Indications for Laboratory Testing

  • Tests generally appear in the order most useful for common clinical situations
  • Click on number for test-specific information in the ARUP Laboratory Test Directory
Test Name and Number Recommended Use Limitations Follow Up
Hepatitis Panel, Acute with Reflex to HBsAg Confirmation 0020457
Method: Qualitative Chemiluminescent Immunoassay

Order to evaluate viral etiology in patients with acute hepatitis

Not recommended for screening asymptomatic patients

Panel includes HAV IgM, HBV core antibody IgM, HBV surface antigen with reflex to confirmation, HCV antibody

   
Hepatitis B Virus Surface Antigen with Reflex to Confirmation 0020089
Method: Qualitative Chemiluminescent Immunoassay 

Initial testing for suspected chronic HBV infection

   
Hepatitis C Virus Antibody by CIA 2002483
Method: Qualitative Chemiluminescent Immunoassay

Initial testing for individuals at risk for HCV infection

One time screening for population born between 1945-1965

 

For positive results, order HCV RNA PCR (quantitative or qualitative)

Order genotyping once diagnosis is established

Hepatitis C Virus RNA Quantitative, Real-Time PCR 0098268
Method: Quantitative Real-Time Polymerase Chain Reaction

Preferred test to confirm active HCV infection following HCV high-positive screen

Establish baseline viral load prior to initiation of therapy

Monitor therapy

Evaluate prognosis and disease progression

Assess transmission of HCV in newborns from HCV-positive mothers

If the assay DID NOT DETECT the virus, the result will be reported as “<1.6 log IU/mL (<43 IU/mL)”; if the assay DETECTED the presence of the virus but was not able to accurately quantify the number of copies, the test result will be reported as “Not Quantified"  
Hepatitis C Virus RNA Quantitative Real-Time PCR with Reflex to Genotype 2002685
Method: Quantitative Real-Time Polymerase Chain Reaction/Sequencing

Preferred reflex test to confirm active HCV infection following HCV high-positive screen

   
Hepatitis C Virus RNA Qualitative PCR 0098264
Method: Qualitative Polymerase Chain Reaction

Quantitative test generally preferred 

Assess transmission of HCV in newborns from HCV-positive mothers

Negative result does not rule out the presence of PCR inhibitors in the patient sample or the presence of HCV RNA concentrations below the level of detection by the assay  
Hepatitis C Virus Genotype by Sequencing 0055593
Method: Polymerase Chain Reaction/Sequencing

Order before initiating HCV therapy to aid in determining therapy of choice, likelihood of response, and probable therapeutic duration

Do not order prior to molecular confirmation of positive HCV screen

Assay does not subtype

Test may be unsuccessful if HCV RNA viral load is <log 2.8 or 600 IU/mL

 
Hepatitis C Virus High-Resolution Genotype by Sequencing 2006898
Method: Polymerase Chain Reaction/Sequencing

Order before initiating HCV therapy to aid in determining therapy of choice, likelihood of response, and probable therapeutic duration

Use for prognosis and treatment selection when a higher level of subtype resolution is required (ie, non 6a/b vs. type 1 and type 1a vs. 1b)

Do not order prior to molecular confirmation of positive HCV screen

   
Hepatitis C Virus (HCV) Genotype with Reflex to HCV High-Resolution Genotype by Sequencing 2009255
Method: Polymerase Chain Reaction/Sequencing

Acceptable reflex panel to use for prognosis and treatment selection when a higher level of subtype resolution is required (ie, non 6a/b vs. type 1 and type 1a vs. 1b)

Do not order prior to molecular confirmation of positive HCV screen

   
Interleukin 28 B (IL28B)-Associated Variants, 2 SNPs 2004680
Method: Qualitative Polymerase Chain Reaction/Qualitative Fluorescence Monitoring

Predict response to PEG-IFNα and RBV therapy for chronic HCV-1 infection

Clinical sensitivity/specificity – unknown

SNPs other than those targeted will not be detected

Usefulness of IL28B-associated SNPs for predicting therapy response for HCV genotypes other than HCV-1 is unknown; lack of favorable genetic factors should not be used to deny therapy

Mutations in genes and nongenetic factors that may affect response to HCV therapy are not detected

Diagnostic errors can occur due to rare sequence variations

 
Inosine Triphosphatase (ITPA) and Interleukin 28 B (IL28B)-Associated Variants, 4 SNPs 2006344
Method: Polymerase Chain Reaction/Single Nucleotide Extensions

Predict response to PEG-IFNα/RBV therapy for chronic HCV-1

Aid in dose planning for chronic HCV-1 infection

Predict risk of RBV treatment-related anemia

Clinical sensitivity/specificity – unknown

Usefulness of IL28B-associated SNPs for predicting therapy response for HCV genotypes other than HCV-1 is unknown; lack of favorable genetic factors should not be used to deny therapy

Mutations in genes and nongenetic factors that may affect response to HCV therapy are not detected

Diagnostic errors can occur due to rare sequence variations

 
Hepatitis C Virus RNA Quantitative bDNA 0051811
Method: Quantitative Branched Chain DNA

Not recommended to confirm active HCV infection; quantitative PCR generally preferred

If used, provide a baseline viral load for monitoring treatment efficacy

Negative result does not rule out the presence of PCR inhibitors in the patient sample or the presence of HCV RNA concentrations below the level of detection by the assay

Low-positive values may occasionally be seen in specimens from patients who are not infected

 
Additional Tests Available
 
Click the plus sign to expand the table of additional tests.
Test Name and NumberComments
Hepatitis A Virus Antibody, IgM 0020093
Method: Qualitative Chemiluminescent Immunoassay

Rule out acute HAV

Hepatitis B Virus Core Antibody, IgM 0020092
Method: Qualitative Chemiluminescent Immunoassay

Rule out HBV

Hepatitis B Virus Surface Antibody 0020090
Method: Quantitative Chemiluminescent Immunoassay

Determine immunity to HBV

Hepatitis C Virus RNA Quantitative bDNA with Reflex to Hepatitis C Virus RNA Quantitative, Real-Time PCR 2002682
Method: Quantitative Branched Chain DNA/Polymerase Chain Reaction

Limited use; Hepatitis C Virus RNA Quantitative, Real-Time PCR preferred

Hepatitis C Virus RNA Quantitative bDNA with Reflex to Genotype 2002681
Method: Quantitative Branched Chain DNA/Sequencing

Preferred test is quantitative PCR following a high-positive HCV screen

FibroSURE, Serum 2004745
Method: Semi-Quantitative Immunologic/Colorimetry/Kinetic/Nephelometry

Provide assessment of liver status following diagnosis of HCV as well as baseline determination of liver status before initiating HCV therapy

Also use for post-treatment assessment of liver status six months after completion of therapy and noninvasive assessment of liver status in patients who are at increased risk of complications from a liver biopsy