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HelpOrder Code LABGOR, HCVDR Hepatitis C Virus Genotypic Antiviral Drug Resistance, Serum
Additional Codes
Order EPIC Code: LABGOR with Mayo Test ID: HCVDR
Ordering Guidance
This test is intended for detection of preexisting antiviral drug resistance-associated substitutions in individuals known to be infected with hepatitis C virus (HCV) genotype 1a, 1b, or 3 (any subtype) and being considered for HCV NS3, NS5A, and NS5B inhibitor combination therapy.
Additional Testing Requirements
Prior to requesting this test, patients must have a confirmed serum or plasma hepatitis C virus (HCV) RNA level of 5000 IU/mL or higher within the preceding 30 days and a known HCV genotype result of 1a, 1b, or 3 (any subtype). The following tests are available to provide these prerequisite results:
-HCVQG / Hepatitis C Virus (HCV) RNA Quantification with Reflex to HCV Genotype, Serum
-HCVQN / Hepatitis C Virus (HCV) RNA Detection and Quantification by Real-Time Reverse Transcription-PCR, Serum
-HCVG / Hepatitis C Virus Genotype, Serum
Shipping Instructions
1. Ship specimen frozen on dry ice only.
2. If shipment will be delayed for more than 24 hours, freeze serum at -20 to -80° C before shipment, and transport on dry ice.
Necessary Information
The following 2 questions must be answered at the time of test ordering (if not ordering electronically, note the answers on the test request):
1. What Is the Hepatitis C Virus (HCV) RNA level in IU/mL within the last 30 days? Provide an answer using the following ranges:
- <5000
- 5000 to 1,000,000
- 1,000,001 to 10,000,000
- 10,000,001 to 100,000,000
- >100,000,000
Note: If the answer to this question is not answered or is “Unknown," testing will be canceled.
2. Does the patient have a known hepatitis C genotype of 1a, 1b, or 3 (any subtype)? Yes or No.
Note: If the answer to this question is "No," testing will be canceled.
Specimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 2.5 mL
Collection Instructions:
1. Centrifuge blood collection tube per manufacturer's instructions (eg, centrifuge and aliquot within 2 hours of collection for BD Vacutainer tubes).
2. Aliquot serum into a plastic vial.
Useful For
Detecting and identifying codon substitutions in the hepatitis C virus (HCV) NS3, NS5A, and NS5B genomic regions that confer resistance to current direct-acting antiviral drugs used for treatment of chronic hepatitis C infection due to HCV genotype 1a, 1b, or 3 (any subtype)
Guiding initiation or change of antiviral drug combinations for the treatment of chronic HCV infection
This assay should not be used as a screening test for HCV infection.
This test should not be ordered for HCV infection due to genotypes 2, 4, 5, or 6.
Testing Algorithm
Testing is successful only if there is sufficient hepatitis C viral (HCV) RNA present in the serum specimen (ie, 5000 IU/mL or above) in the preceding 30 days. If the HCV RNA level within the last 30 days is unknown or not provided, then this test will be canceled.
For more information see Chronic Hepatitis C Treatment and Monitoring Algorithm: Direct Antiviral Agent (DAA) Combination.
Special Instructions
Method Name
Polymerase Chain Reaction (PCR) followed by Next-Generation Sequencing
Reporting Name
HCV Genotypic Drug Resistance, SSpecimen Type
Serum SSTSpecimen Minimum Volume
1.6 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum SST | Frozen (preferred) | 60 days | ALIQUOT TUBE |
| Refrigerated | 7 days | ALIQUOT TUBE |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Gross icterus | OK |
Reference Values
An interpretive report will be provided.
Method Description
This test utilizes the commercially available Sentosa SQ HCV Genotyping Assay, v 2.0, which is a next-generation sequencing assay based on a "sequencing by synthesis" method. The assay is designed to specifically amplify 4 sequences ranging from 436 to 1112 base pairs in length, located in 3 different non-structural (NS) regions of the hepatitis C virus (HCV) genome: NS3 (79 resistance-associated substitutions [RAS], RAS at 17 codon positions), NS5A (65 RAS at 15 codon positions), and NS5B (13 RAS at 6 codon positions). Clinical serum specimens are subjected to automated HCV RNA extraction and purification, followed by reverse-transcription polymerase chain reaction amplification of HCV target sequences, with both a system control and a positive control included in each assay run for quality control purposes. Automated DNA library preparation is performed using the amplified products, including enzymatic shearing, adapter ligation, purification, and normalization, prior to DNA template preparation and sequencing. Sequencing reactions are conducted with the Ion Personal Genome Machine sequencer, and the assembled sequence data are analyzed using proprietary analysis and interpretive software applications. HCV genotype-specific antiviral drug-resistance interpretations are based on a combination of US Food and Drug Administration-approved prescribing information for the drug and professional society practice guidelines using a 10% variant detection cutoff threshold.(Instruction manual: ViroKey SQ FLEX Genotyping Assay (4x16). Vela Diagnostics; V2.2, 2023)
Day(s) Performed
Once per week
Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
87900
87902
87999 (if appropriate for government payers)
Forms
If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.