National case definition: Hepatitis C

Date of last revision/review: September 2024

Effective date: January 2025

National notification

Only confirmed cases of disease should be notified

Type of surveillance

Routine case-by-case notification to the federal level

Case classification

For adults, adolescents and children >36 months of age AND for children ≤36 months of age whose suspected mode of exposure is not perinatal^{Footnote 1}

Confirmed case: Acute or recent infection

• Detection of hepatitis C virus RNA (HCV RNA) or detection of hepatitis C virus antigen (HCV Ag)

  and

• Clinical hepatitis (jaundice or peak elevated total bilirubin levels in serum ≥ 50.0 µmol/L or peak elevated serum alanine aminotransferase [ALT] >200 IU/L) and no other known cause for clinical hepatitis

  and

• Negative anti-hepatitis A virus IgM (anti-HAV IgM) and negative anti-hepatitis B core IgM (anti-HBc IgM)

or

• Detection of HCV RNA or HCV Ag in a person with a documented negative test within the preceding 12 months for hepatitis C virus antibodies (anti-HCV) or HCV RNA

or

• Detection of anti-HCV in a person with documented negative anti-HCV within the preceding 12 months

Confirmed case: Chronic infection

Does not meet criteria for "Confirmed case - Acute or recent infection"

and

• Detection of HCV RNA

  or

• Detection of HCV Ag

Confirmed case: Resolved infection^{Footnote 2}

• Does not meet criteria for "Confirmed case - Acute or recent infection" or "Confirmed case – Chronic infection"
• and
• Negative HCV RNA test result
• and
• Detection of anti-HCV

Confirmed case: Unspecified hepatitis C^{Footnote 3}

• Does not meet criteria for "Confirmed case - Acute or recent infection" or "Confirmed case - Chronic infection" or "Confirmed case - Resolved infection"
• and
• Detection of anti-HCV

For children ≤36 months of age whose suspected mode of exposure is perinatal^{Footnote 1}

Confirmed case: Perinatal infection

• Detection of HCV RNA
• or
• Detection of anti-HCV at ≥ 18 months of age

Laboratory comments

Hepatitis C infection is characterized by the appearance of HCV RNA, HCV Ag and anti-HCV. It may take 6-10 weeks for anti-HCV to be detected in the blood following exposure. HCV RNA is detectable within 1-2 weeks and HCV Ag within about 2 weeks of infection. HCV RNA and HCV Ag can identify acute HCV infection even in the absence of anti-HCV test positivity. HCV Ag tests are generally less sensitive than HCV RNA tests. HCV RNA levels can fluctuate over the course of infection. Positive anti-HCV results should be confirmed with follow-up testing as per provincial/territorial protocol. Immunocompromised individuals may not develop anti-HCV and may require HCV RNA testing to confirm and diagnose infection.

Between 15% and 30% of adults with acute HCV will have spontaneous clearance within 6 months of infection. Those who spontaneously clear an HCV infection will typically demonstrate anti-HCV without detectable HCV RNA or HCV Ag. For a minority of cases and typically after a prolonged time period, anti-HCV may become negative after spontaneous resolution or cure of hepatitis C. Individuals with resolved or successfully treated infections generally require HCV RNA testing to confirm and diagnose a new infection.

Between 20% and 30% of infants with perinatally-acquired hepatitis C infections (i.e. not acquired via healthcare) experience spontaneous clearance by 2-3 years of age. Umbilical cord blood should not be used for infant testing. Positive anti-HCV results in infants younger than 18 months may represent placental transfer of antibodies. HCV RNA testing of infants should be delayed until 8 weeks of age to avoid false negative results.

Follow provincial or territorial recommendations for reporting hepatitis C cases detected by emerging testing technologies e.g. dried blood spot (DBS) and point of care tests (POCT).

ICD code(s)

ICD-11 code(s)

1E50.2, 1E51.1

ICD-10 code(s)

B17.1, B18.2

Comments

Cases should be reported in the context of their initial identification and not be reclassified with longitudinal change in status.

Individuals who have achieved sustained virologic response (SVR) after treatment through documented undetectable HCV RNA at least 12 weeks post-end-of-treatment (SVR-12), then have a subsequent detectable HCV RNA result within 12 months of SVR-12 date should be considered as newly infected for surveillance purposes, even though these cases may rarely represent late post-treatment relapses.

References

Aebi-Popp K. et al. The Swiss HIV Cohort Study. Rapid decline of anti-hepatitis C virus (HCV) antibodies following early treatment of incident HCV infections in HIV-infected men who have sex with men. HIV Med. 2018 Jul;19(6):420-425. https://onlinelibrary.wiley.com/doi/10.1111/hiv.12602

Barreiro P et al. Longitudinal changes in viral RNA concentration in patients with chronic hepatitis C and/or HIV infection in the absence of antiviral therapy. J Clin Virol. 2013 Oct;58(2):391-5. https://pubmed.ncbi.nlm.nih.gov/23910933/

Bitnum A; Canadian Paediatric Society, Infectious Diseases and Immunization Committee. The management of infants, children, and youth at risk for hepatitis C virus infection. Paediatr Child Health. 2021 Nov 11;26(7):440-441. doi: 10.1093/pch/pxab073. Full text retrieved 2023 Feb 1 from: https://cps.ca/en/documents/position/the-management-of-hepatitis-c-virus

Centers for Disease Control and Prevention (CDC). Testing for HCV infection: an update of guidance for clinicians and laboratorians. MMWR Morb Mortal Wkly Rep. 2013 May 10;62(18):362-5.

Hajarizadeh B et al. Patterns of hepatitis C virus RNA levels during acute infection: the InC3 study. PLoS One. 2015 Apr 2;10(4):e0122232. Patterns of hepatitis C virus RNA levels during acute infection: the InC3 study - PubMed (nih.gov)

Kee KM. et al. Decreased anti-hepatitis C virus titer and associated factors in chronic hepatitis C patients after sustained virological response: a prospective study. J Gastroenterol Hepatol. 2012 Jun;27(6):1106-11. https://onlinelibrary.wiley.com/doi/10.1111/j.1440-1746.2011.06946.x

Micallef JM, Kaldor JM, Dore GJ. Spontaneous viral clearance following acute hepatitis C infection: a systematic review of longitudinal studies. J Viral Hepat. 2006 Jan;13(1):34-41. doi: 10.1111/j.1365-2893.2005.00651.x.

Public Health agency of Canada. Case Definitions for Communicable Diseases Under National Surveillance - 2009. Canada Communicable Disease Report; November 2009, 35S2. Retrieved March 30 2023, from http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/09vol35/35s2/index-eng.php

Shah H, Bilodeau M, Burak KW, Cooper C, Klein M, Ramji A, Smyth D, Feld JJ; Canadian Association for the Study of the Liver. The management of chronic hepatitis C: 2018 guideline update from the Canadian Association for the Study of the Liver. CMAJ. 2018 Jun 4;190(22):E677-E687. doi: 10.1503/cmaj.170453.

Tang et al. 2017. Diagnostic accuracy of tests to detect Hepatitis C antibody: a meta-analysis and review of the literature. BMC Infect Dis. 17(Suppl 1):695. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5688422/pdf/12879_2017_Article_2773.pdf

World Health Organization. WHO guidelines on hepatitis B and C testing. 2017. Retrieved 2023 Mar 30 from: https://www.who.int/publications/i/item/9789241549981

Related links

• Hepatitis C
• Notifiable diseases online