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 perferred)
        • Quantitative or qualitative PCR test negative – infected but recovered or false-positive screen  
        • Quantitative or qualitative PCR test positive – currently infected (chronic HCV)
  • Further testing once initial HCV testing is positive 
    • Perform HCV genotyping – genotype affects rate of treatment success
      • 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 to predict therapeutic response and aid in dose planning, respectively
    • Liver biopsy if patient is HCV genotype 1 – may be considered by gastroenterologist

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)
    • U.S. Preventative Services Task Force found insufficient evidence to recommend screening
    • CDC, 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
      • CDC additional recommendations (2012) – one time testing for persons born between 1945-1965
        • Population has disproportionately high rate of HCV infection and related disease
    • For pregnant females, routine HCV screening is not recommended

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
  • Transmission – parenteral (only 50% have one of these known routes)

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 – strong pretreatment predictor of treatment response in HCV genotype 1
    • SNPs located in IL28B gene region impact probability of spontaneous clearance, rate of progression to chronic infections, and sustained virologic response to PEG-IFN/RBV treatment and triple therapy in patients infected with HCV genotype 1
    • SNPs rs12979860 C/C and rs8099917 T/T genotypes – associated with favorable response
  • Inosine triphosphatase (ITPA) genotype – strong predictor of treatment-related anemia (common side effect of HCV combination treatment)
    • SNPs rs1127354 A/A and A/C and rs7270101 C/C and C/A genotypes – associated with decreased hemolytic side effects from RBV therapy

Risk Factors

  • Transfusion with blood or blood products prior to 1990
    • Risk is 1/400,000 units transfused
  • Infected with another blood-borne pathogen (eg, HBV, HIV)
  • History of IV drug or intranasal cocaine use
  • HCV-positive sexual partner
  • Organ transplant recipient

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

  • Moderately effective
  • 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

Screen individuals at risk for HCV infection

  

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 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

  
Hepatitis C Virus Genotyping 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

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

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

May be used for prognosis and treatment selection requiring a higher level of subtype resolution such as non 6a/b versus type 1 and type 1a versus 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

Detect genetic variants associated with interleukin 28 B (IL28B) that may aid in predicting probability of therapeutic response (IL28B)

SNPs other than those targeted will not be detected

For HCV genotypes other than type 1, the usefulness of these SNPs for predicting response to therapy is not well established

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

Detect genetic variants associated with interleukin 28 B (IL28B) and inosine triphosphatase (ITPA) that may aid in predicting probability of therapeutic response (IL28B) and dose planning (ITPA)

    
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 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