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Hepatitis C Genotyping


Blood
Test performed by: LabPLUS VIM Molecular Diagnostics


Do not use heparin tubes

A dedicated specimen (i.e. no other tests to be performed) is required for this assay.

A current viral load result MUST accompany a request for genotyping. Samples without a current viral load will not be processed.

A minimum HCV viral load of 3.0 log IU/ml is required for successful typing.

(Current viral load = within the last month for untreated chronic HCV

                                 = immediately prior to genotyping for treated HCV.)


Specimen Collection
Micro-EDTA800 uL Paediatric Micro-EDTA Plasma (Preferred)
PPT4 mL Adult PPT Plasma (Preferred)
EDTA4 mL Adult EDTA Plasma
Plain4 mL Adult Plain Serum
SST3.5 mL Adult SST Serum
Turnaround Time: Between 1 week and 2 weeks

Only performed Monday - Friday


Assay Method

HepC Genotyping is determined using Roche cobas 4800 System. This is a highly sensitive real-time PCR-based test for the qualitative identification of HCV genotypes 1 to 6 and genotypes 1a and 1b subtypes in human plasma or serum.

  The assay uses three different target regions in the HCV genome (5'-UTR, Core, NS5B) to achieve optimal genotyping and subtyping concordance when compared to sequencing. In dual infections it has the capability to detect both genotypes, down to a ratio of 1: 100.

Hepatitis C genotyping involves two main procedures:

1. Sample preparation where hepatitis C viral RNA is extracted from human serum or plasma.

2. HCV amplification with reverse transcription followed by polymerase chain reaction using the cobas HCV GT assay. This is a real-time, reverse transcription-PCR (RT-PCR) assay using 3 pools of PCR primers. One set of primers targets the 5'untranslated region (5'UTR) for detection of all HCV types and additionally distinguishes GT 2,3 and 6. The second pool targets the core regions for GT 1,4 and 5. The third pool targets NS5b for subtyping of GT 1a and 1b.  

    

 


Diagnostic Use and Interpretation

HCV is an enveloped virion containing a single-stranded positive sense RNA genome of approximately 9,500 nucleotides. It has been identified as the major etiological agent for post-transfusion non-A and non-B hepatitis worldwide. Based on genetic similarity, HCV has been classified into six major genotypes (1-6) and numerous subtypes. HCV genotype is predictive of the response of HCV-infected patients to peginterferon/ ribavirin combination therapy and may influence response to other anvirals . Before starting combination therapy, it is recommended that the genotype be determined so that the patient can receive the most appropriate therapy regimen. 

 

HCV PCR


Contact Information

For further information contact the laboratory  (contact via Lablink: 22000 or (09) 307-8995 or 0800 522 7587) ,or:
the Virology team virology@adhb.govt.nz

 


Specimen Transport Instructions for Referring Laboratories

SPECIMEN REQUIREMENTS



Last updated at 14:19:33 08/07/2020