Hepatitis C – Diagnostic Serology

*Uncontrolled print copy. Valid only on day of print: 24 Aug 2019.

Testing Indications

Testing for Hepatitis C Virus (HCV) antibodies is indicated for the work-up patients with suspected chronic 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, etc.), for determining past exposure, and as part of an epidemiologic investigation (e.g. infection control breach). Testing for HCV antibodies during the work-up of a patient with suspected acute viral hepatitis is for baseline purposes as there is no HCV IgM test currently available.

Specimen Collection and Handling

Specimen Requirements

Test Requested	Required Requisition(s)	Specimen Type	Minimum Volume	Collection Kit
Hepatitis C¹	General Test Requisition	Serum	1.0 mL	Blood, clotted – Vacutainer tubes (SST)

Submission and Collection Notes

Detailed instructions for ordering Hepatitis C testing are available to assist you with completing the “Hepatitis Serology boxes” in section 3 of the General Test Requisition.

For testing all Hepatitis markers, HIV, HTLV, Syphilis and Rubella, you only are required to submit two FULL red top or serum separator tubes (SST).

Do NOT submit glass tubes.

Limitations

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

Preparation Prior to Transport

Label the specimen container with the patient’s full name, date of collection and one other unique identifier such as the patient’s date of birth or Health Card Number. Failure to provide this information may result in rejection or testing delay.

Centrifuge if using SST. Place specimen in biohazard bag and seal. Specimens should be stored at 2-8°C following collection.

Specimens more than 7 days post collection will not be tested.

Special Instructions

Instructions for using SST tubes are found in the document titled: LAB-SD-008, Blood Collection using Serum Separator Tubes

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

Hepatitis C – Serology testing is performed daily Monday to Friday.

Turnaround time is up to 3 days from receipt by PHO laboratory for Non-reactive antibody results. Reactive and Indeterminate HCV antibody results are available and reported within 6 days.

Repeat testing may be indicated in those with ongoing risk factors for the acquisition of HCV.

Once a patient tests positive for HCV antibodies, other than in cases of maternal antibody transfer, there is no value in repeating the test as they will remain antibody positive for life regardless of whether they have cleared the virus or are chronic carriers.

STAT and Critical Samples Testing

Testing on ‘Source Patient’ for Needlestick/Occupational Exposure if warranted

Reporting

Results are reported to the ordering physician or health care provider as indicated on the requisition.

Specimens that are positive for Hepatitis C virus are to be reported to the Medical Officer of Health as per Health Protection and Promotion Act.

Test Methods

Specimens for Hepatitis C antibody are initially tested using a chemiluminescent microparticle immunoassay (CMIA) for the qualitative detection of Hepatitis C antibody in human serum. Specimens that are positive for Hepatitis C antibodies on the screening test are tested using a supplemental test for confirmation.

Interpretation

Final results for Hepatitis C antibodies are based on the results of both the screening and confirmatory test.

A confirmed positive Hepatitis C antibody result is evidence of infection with the hepatitis C virus. It cannot distinguish between recent or past infection. In addition, a positive Hepatitis C antibody result does NOT indicate immunity to hepatitis C virus.

A negative Hepatitis C antibody test result indicates absence of infection with hepatitis C virus.

An inconclusive result for Hepatitis C antibodies (reported when the screening test is positive, but the second test is negative) may be due to early infection in which case a complete antibody has not yet developed or it may be due to a biological false positive result due to cross-reacting or non-specific antibodies. Follow testing on a fresh sample is indicated.