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Test Code HCVG Hepatitis C Virus Genotype, Serum

Reporting Name

HCV Genotype, S

Useful For

Determining hepatitis C virus (HCV) genotype (1 to 5) to guide antiviral therapy in patients with chronic hepatitis C

 

Differentiating between HCV subtypes 1a and 1b

 

This assay should not be used as a screening test for HCV infection. It should be performed only on specimens obtained from patients confirmed to have HCV RNA levels in serum of 500 IU/mL or higher.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum SST


Shipping Instructions


Ship specimen frozen on dry ice only. If shipment will be delayed for more than 3 days, freeze serum at -20° C or colder (up to 42 days) until shipment on dry ice.



Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube: Serum gel (red-top tubes are not acceptable)

Submission Container/Tube: Plastic vial

Specimen Volume: 5 mL

Collection Instructions:

Within 2 hours of collection, centrifuge and aliquot serum into a plastic vial.

Additional Information:

1. This test requires a minimum hepatitis C virus viral load of 500 IU/mL within the 30 days preceding collection.

2. Serum specimens previously submitted to other laboratories for non-microbiology tests are not acceptable for add-on test requests due to possible sample-to-sample carryover from automation used for those tests.


Specimen Minimum Volume

1.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum SST Frozen (preferred) 42 days ALIQUOT TUBE
  Refrigerated  72 hours ALIQUOT TUBE

Reference Values

Undetected

Day(s) Performed

Monday through Friday

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

87902

Clinical Information

Unique nucleotide sequences of certain regions (eg, 5'-noncoding, core, NS5b) of the hepatitis C virus (HCV) genome allow classification of HCV into 6 major genotypes or clades (1-6), based on the most recently proposed HCV genotype nomenclature. In the United States, the most frequently encountered HCV genotypes are 1a and 1b, followed by genotypes 2 and 3. Worldwide geographic distribution, disease outcome, and response to antiviral therapy differ among the genotypes. Therefore, reliable methods for genotype determination are important for proper selection of antiviral therapy and optimal patient management. Infections with HCV genotypes 2 and 3 have better therapeutic response rates (80%-90%) than genotypes 1 and 4 (40%-50%) to previous standard combination therapy (ribavirin plus pegylated interferon alpha-2a or alpha-2b). Duration of such combination therapy is 24 weeks for chronic HCV genotype 2 and 3 infections in patients who show early virologic response (>2 log or 100-fold decrease in HCV RNA or no detectable HCV RNA at week 12 of therapy), while patients with chronic HCV genotype 1 and 4 infections receive a minimum of 48 weeks of such combination therapy if early virologic response is achieved (undetectable HCV RNA at week 4 of therapy).

 

Therapeutic response rates for HCV genotype 1 infection are improved significantly (80%-90%) when oral direct acting antiviral agents (eg, daclatasvir, sofosbuvir, ledipasvir + sofosbuvir, velpatasvir + sofosbuvir, glecaprevir + pibrentasvir, elbasvir + grazoprevir, velpatasvir + voxilaprevir + sofosbuvir) are added or used in lieu of interferon-based combination therapy.

 

The American Association for the Study of Liver Diseases and Infectious Disease Society of America recommendations for testing, managing, and treating hepatitis C are available at www.hcvguidelines.org/contents.

 

The following algorithms are available:

-Chronic Hepatitis C Treatment and Monitoring Algorithm: Direct Antiviral Antigen (DAA) Combination

-Hepatitis C: Testing Algorithm for Screening and Diagnosis

Report Available

1 to 6 days

Reject Due To

Gross hemolysis OK
Gross lipemia OK

Method Name

Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) followed by Hybridization with Sequence-Specific, Fluorescent-Labeled Oligonucleotide Probes

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
HCVGR HCV Genotype Resolution, S No No

Forms

If not ordering electronically, complete, print, and send 1 of the following:

-Gastroenterology and Hepatology Test Request (T728)

-Microbiology Test Request (T244)