Hepatitis C – Diagnostic Serology

This page provides serology testing information for Hepatitis C Virus at Public Health Ontario (PHO).

Updates

Specimen minimum volume and handling instructions have been updated.
Hepatitis C diagnostic testing algorithm has been updated to facilitate better test utilization.

*Uncontrolled print copy. Valid only on day of print: 28 May 2023.

Testing Indications

Testing for Hepatitis C Virus (HCV) antibodies is indicated for the work-up of patients with suspected chronic or acute viral hepatitis, or those with unexplained elevation in their liver function tests (e.g. ALT, AST), for screening those at high risk of infection (e.g. intravenous drug users, individuals for correctional facilities, etc.), for determining past exposure, needle stick or occupational exposure, and as part of an epidemiologic investigation (e.g. infection control breach or outbreak situation).

Specimen Collection and Handling

Specimen Requirements

Test Requested	Required Requisition(s)	Specimen Type	Minimum Volume	Collection Kit
Hepatitis C	General Test Requisition	Serum	1.5 mL	Serum Separator Tube (SST)

Submission and Collection Notes

Complete all fields of the requisition form, including:

Test(s) requests and indications for testing
Patient setting/population/source
Relevant clinical information

Label the specimen container(s) with the patient’s first and last name, date of collection, and one other unique identifier such as the patient’s date of birth or Health Card Number. For additional information see: Criteria for Acceptance of Patient Specimens. Failure to provide this information may result in rejection or testing delay.

Refer to instructions for ordering Hepatitis C testing for how to complete the “Hepatitis Serology” section of the general test requisition.

Submit centrifuged serum separator tubes (SST) for serological assays.

One FULL 5 mL SST is required for testing a combination of Hepatitis virus, HTLV, syphilis and rubella. If a full tube cannot be drawn, submit two tubes.

Do not submit glass tubes.

Limitations

Haemolysed, icteric, lipemic or microbially contaminated serum is not recommended for testing.

Storage and Transport

Centrifuge the specimen tube as per the recommended laboratory protocol.

Place specimen tube in biohazard bag and seal. Place completed General Test Requisition in the pouch at the front of the biohazard bag.

Specimen tubes should be stored at 2-8°C following collection and centrifugation, and should be shipped to PHO’s laboratory on ice packs within 3 days of collection. Specimen tubes received more than 6 days post-collection will not be tested. If delayed shipping is anticipated, remove serum from clot and store frozen at -20°C or colder, and ship on dry ice.

All clinical specimens must be shipped in accordance to the Transportation of Dangerous Good Act.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

HCV serology testing is performed daily Monday to Friday.

Turnaround time may be up to 3 business days from receipt of the specimen at PHO’s Laboratory for non-reactive specimens and up to 6 business days for reactive and indeterminate specimens.

STAT and Critical Specimens Testing
If warranted, testing of ‘Source Patient’ for needle stick/occupational exposure is expedited.

STAT specimens must be shipped separately from routine specimens in a clearly marked package indicating ‘STAT’ and handled in accordance with the Canadian Biosafety Standards and shipped in accordance with the Transportation of Dangerous Goods Regulations. Failure to ship separately will delay testing.

Please notify PHO’s Laboratorys Customer Service Centre at 416-235-6556/1-877-604-4567 immediately when a STAT sample is sent. Contact the After-Hours Emergency Duty Officer at 416-605-3113 outside of PHO’s laboratory operating hours.

Test Methods

PHO follows an orthogonal algorithm for HCV antibody testing:

HCV antibody screening: chemiluminescent microparticle immunoassay (CMIA) for the qualitative detection of HCV antibody in human serum. This test does not distinguish between IgG and IgM.
HCV antibody supplemental: chemiluminescent immunoassay (CLIA) for qualitative detection of HCV antibody in human serum. This test only detects IgG.

Algorithm

Serum specimens submitted for HCV antibody testing are screened by CMIA. Non-reactive CMIA specimens are reported as non-reactive and no supplemental testing will be performed.

Reactive CMIA specimens:

within PHO’s internally established threshold will be tested for HCV antibody supplemental testing.
above PHO’s internally established threshold will not be tested for HCV antibody supplemental testing, and will be reported right away.

All first-time HCV antibody reactive specimens will automatically be tested for HEPC RNA Viral Load.

Interpretation

Results should be interpreted in the context of the clinical history, signs and symptoms of the patient. The table below provides a general overview of possible interpretations. A PHO Microbiologist is available for questions about Hepatitis C serology results and interpretations.

Table 1. HCV antibody serology results interpretation table for patients >18 months

HCV Antibody Screening Result	HCV antibody Supplemental Result	Possible Interpretations/Recommendations
Non-reactive	Not tested	No evidence of HCV antibody. Acute HCV infection window period. HCV RNA testing is recommended for patients who have had recent exposure or are suspected to be in a window period.
Indeterminate	Not tested	Inconclusive result for HCV antibody. HCV RNA testing is recommended. No further testing is recommended for patients that have two inconclusive HCV antibody and not detected HCV RNA viral load results that are 6-8 weeks apart.
Reactive	Non-reactive	Inconclusive result for HCV antibody. HCV RNA testing is recommended. No further testing is recommended for patients that have two inconclusive HCV antibody and not detected HCV RNA viral load results that are 6-8 weeks apart.
Reactive	Indeterminate	Inconclusive result for HCV antibody. HCV RNA testing is recommended. No further testing is recommended for patients that have two inconclusive HCV antibody and not detected HCV RNA viral load results that are 6-8 weeks apart.
Reactive	Reactive	Evidence of HCV antibody. The presence of HCV antibody does not indicate immunity but suggests prior exposure to the Hepatitis C virus. Patients with first-time HCV antibody reactive will be automatically tested for HCV RNA Viral load.
Reactive	Not tested*	Evidence of HCV antibody. The presence of HCV antibody does not indicate immunity but suggests prior exposure to the Hepatitis C virus. Patients with first-time HCV antibody reactive will be automatically tested for HCV RNA Viral load.

*HCV antibody supplemental test will not be performed for screening positive patients with previous positive history.

Table 2. HCV antibody serology results interpretation table for patients ≤18 months

HCV Antibody Screening	HCV antibody Supplemental	Possible Interpretations/Recommendations
Non-reactive	Not tested	No evidence of HCV antibody. HCV RNA testing, collected at >6 weeks of age, is recommended for patients who have had recent exposure.
Indeterminate	Not tested	Inconclusive result for HCV antibody. The HCV IgG antibody detected may represent maternal transfer of antibodies which may persist for up to 18 months. HCV RNA testing, collected at >6 weeks of age, is recommended.
Reactive	Non-reactive	Inconclusive result for HCV antibody. The HCV IgG antibody detected may represent maternal transfer of antibodies which may persist for up to 18 months. HCV RNA testing, collected at >6 weeks of age, is recommended.
Reactive	Indeterminate	Inconclusive result for HCV antibody. The HCV IgG antibody detected may represent maternal transfer of antibodies which may persist for up to 18 months. HCV RNA testing, collected at >6 weeks of age, is recommended.
Reactive	Reactive	Evidence of HCV antibody. The HCV IgG antibody detected may represent maternal transfer of antibodies which may persist for up to 18 months. Patients with first-time HCV antibody reactive will be automatically tested for HCV RNA Viral load.
Reactive	Not tested*	Evidence of HCV antibody. The HCV IgG antibody detected may represent maternal transfer of antibodies which may persist for up to 18 months. Patients with first-time HCV antibody reactive will be automatically tested for HCV RNA Viral load.

*HCV antibody supplemental test will not be performed for screening positive patients with previous positive history.

Reporting

Results are reported to the physician, authorized health care provider (General O. Reg 45/22, s.18) or submitter as indicated on the requisition.

Specimens that are reactive for HCV antibody are reported to the Medical Officer of Health as per the Ontario Health Protection and Promotion Act.

*Uncontrolled print copy. Valid only on day of print: 28 May 2023.

Contact Laboratory Customer Service

Laboratory Services

customerservicecentre@oahpp.ca

Updated 30 March 2023