Department of Microbiology

Hepatitis C Viral RNA detection (PCR)

Choice of Appropriate Test

Hepatitis C PCR is used in the evaluation of patients with clinically active hepatitis C and in monitoring those undergoing interferon therapy. The growing use of molecular technology has led to some confusion regarding appropriate testing for Hepatitis C. Two molecular tests are currently offered by this laboratory.

• The Qualitative Hepatitis C RNA test is performed to determine active replication of virus and is useful in confirming a diagnosis of active hepatitis C. This test is performed when a request specifies "Hep C PCR", "Hep C RNA" or "qualitative Hep C test".
• The Quantitative Hepatitis C RNA assay or Viral Load is used in conjunction with therapy and may be performed before, during or after treatment to demonstrate reduction in viral numbers. Following establishment of a baseline, responses to therapy are determined by measurements in serial samples. This test is not used for diagnostic purposes.

Specimen Collection

The test is performed on serum or on plasma from EDTA or ACD only; other anticoagulants are unsuitable. A serum separation tube (gold top) may be used. For qualitative testing, serum or plasma must be separated within six hours of collection. If submitted directly to this laboratory within 48 hours of collection, the sample may be held at 2-8°C; otherwise it must be stored at -20°C to -80°C and transported frozen. For the quantitative test separation must be carried out within three hours and the serum maintained at -20 to -80degreesC.

Therapy

Please indicate if the patient is undergoing antiviral therapy for chronic Hepatitis C infection.

Frequency of Testing

The qualitative assay is performed once per week, normally on a Thursday.
Quantitative testing requires a batch of ten specimens and is performed at the first opportunity after that number of requests has been received, normally twice per month.

Charging

Medical benefits are payable as follows:

1. for the qualitative assay on specimens from patients who meet certain criteria as specified in MBS 69444, under which at least one of the following criteria must be satisfied:
   a) the patient is Hepatitis C sero-positive and has normal liver function tests on 2 occasions 6 months apart
   b) the patient's serological status is uncertain after testing
   c) the test is performed for the purpose of :
   (i) determining the Hepatitis C status of an immunosuppressed or immunocompromised patient; or
   (ii) the detection of acute Hepatitis C prior to seroconversion where considered necessary for the clinical management of the patient; not exceeding one episode in a 12 month period.
2. for the qualitative assay for patients undertaking antiviral therapy for chronic HCV hepatitis (not exceeding 4 episodes in a 12 month period) as specified in MBS 69445.
3. for the quantitative assay (viral load) as specified in MBS 69442.

Note: all these items are subject to Rule 20:

"Hepatitis C sero-positive", for a patient means 2 different assays of Hepatitis C antibodies are positive; "serological status is uncertain" for a patient means any result where 2 different assays of Hepatitis C antibodies are inconclusive.

Hepatitis C Genotyping

This test is not performed in this laboratory and is referred to ICPMR Westmead. Results may take 7-14 days. A medical benefit is payable for Hepatitis C Genotyping as specified in MBS 69443.

For further information

please contact Philip Cunningham, Centre for Immunology ext 2110

January 2002