Test Catalog

Test Id : HCVDR

Hepatitis C Virus Genotypic Antiviral Drug Resistance, Serum

Useful For
Suggests clinical disorders or settings where the test may be helpful

Detection and identification of 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.

Highlights

This assay uses next-generation sequencing to detect and identify hepatitis C virus (HCV) antiviral drug resistance in patients with chronic hepatitis C and those being considered for direct-acting antiviral (DAA) drug combination therapy.

 

This test can be used to predict the likelihood of a curative response to current US Food and Drug Administration-approved DAA drug combinations used for treatment of chronic hepatitis C.

Reflex Tests
Lists tests that may or may not be performed, at an additional charge, depending on the result and interpretation of the initial tests.

Test Id Reporting Name Available Separately Always Performed
HCVQN HCV RNA Detect/Quant, S Yes No

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Testing is successful only if there is sufficient hepatitis C viral (HCV) RNA present in the serum specimen (ie, 50,000 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 HCVQN / Hepatitis C Virus (HCV) RNA Detection and Quantification by Real-Time Reverse Transcription-PCR (RT-PCR), Serum will be performed at an additional charge. See Necessary Information.

 

For more information, see Chronic Hepatitis C Treatment and Monitoring Algorithm: Direct Antiviral Agent (DAA) Combination

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Name
A short description of the method used to perform the test

Polymerase Chain Reaction (PCR) followed by Next-Generation Sequencing

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

HCV Genotypic Drug Resistance, S

Aliases
Lists additional common names for a test, as an aid in searching

HCV

HCVDR

HCV DAA resistance

HCV genotype

HCV genotyping

HCV drug resistance

HCV resistance

HCV NGS

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Testing is successful only if there is sufficient hepatitis C viral (HCV) RNA present in the serum specimen (ie, 50,000 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 HCVQN / Hepatitis C Virus (HCV) RNA Detection and Quantification by Real-Time Reverse Transcription-PCR (RT-PCR), Serum will be performed at an additional charge. See Necessary Information.

 

For more information, see Chronic Hepatitis C Treatment and Monitoring Algorithm: Direct Antiviral Agent (DAA) Combination

Specimen Type
Describes the specimen type validated for testing

Serum SST

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 50,000 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 (RT-PCR), Serum

-HCVG / Hepatitis C Virus Genotype, Serum

Shipping Instructions

1. Freeze serum immediately, and ship specimen frozen on dry ice only.

2. If shipment will be delayed for more than 24-hours, freeze serum at -20 to -80 degrees C (for up to 60 days) prior to shipment 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 HCV RNA level in IU/mL within the last 30 days? (select answer option)

- <50,000

- 50,000 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 either not answered or is "Unknown," the HCVQN / Hepatitis C Virus (HCV) RNA Detection and Quantification by Real-Time Reverse Transcription-PCR (RT-PCR), Serum will be added and performed at an additional charge to determine if serum specimen is suitable for this test.

2. Does the patient have a known hepatitis C genotype of 1a, 1b, or 3 (any subtype)? Answer "Yes" or "No".

Note: Test orders for submitted specimens with a "No" answer to this question will be canceled.

ORDER QUESTIONS AND ANSWERS

Question ID Description Answers
HCVLR HCV RNA level IU/mL last 30 days = <50,000
50,000 to 1,000,000
1,000,001 to 10,000,000
10,000,001 to 100,000,000
>100,000,000
HCVKG Is known HCV genotype 1a, 1b, or 3? Yes
No

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

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 collection tube manufacturer's instructions (eg, centrifuge and aliquot within 2 hours of collection for BD Vacutainer tubes).

2. Aliquot serum into plastic vial.

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Forms

If not ordering electronically, complete, print, and send a Microbiology Test Request (T732) with the specimen. 

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

1.6 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Serum SST Frozen (preferred) 60 days ALIQUOT TUBE
Refrigerated 7 days ALIQUOT TUBE

Useful For
Suggests clinical disorders or settings where the test may be helpful

Detection and identification of 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
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Testing is successful only if there is sufficient hepatitis C viral (HCV) RNA present in the serum specimen (ie, 50,000 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 HCVQN / Hepatitis C Virus (HCV) RNA Detection and Quantification by Real-Time Reverse Transcription-PCR (RT-PCR), Serum will be performed at an additional charge. See Necessary Information.

 

For more information, see Chronic Hepatitis C Treatment and Monitoring Algorithm: Direct Antiviral Agent (DAA) Combination

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Interferon-free, direct antiviral agent (DAA) drug combination therapy is now a standard of care for patients with chronic hepatitis C virus (HCV) infection. However, poor compliance with therapy and the existence of pretreatment antiviral drug resistance may compromise efficacy of such drug therapy. Naturally occurring (preexisting) or treatment-induced mutations in the viral genomic sequences that are targets of such antiviral agents can lead to antiviral resistance and therapeutic failure. Clinical trials and postmarketing studies of DAA therapy indicated that preexisting, resistance-associated substitutions (RAS) in the relevant HCV genomic regions of certain genotypes or emergence of certain RAS during DAA therapy can lead to treatment failure. Per current recommendations from the US Food and Drug Administration (FDA) and professional society practice guidelines (see table and Clinical Reference section), use of certain FDA-approved DAA drugs for treating chronic HCV due to genotypes 1a, 1b, and 3 (any subtype) requires pretreatment testing for RAS in the relevant HCV genomic regions to guide selection of optimal DAA combination therapy.

 

Table.

HCV genomic target of DAA drug

HCV genotype

1a

1b

3 (any subtype)

NS3/4

Glecaprevir(a)

Grazoprevir(b)

Voxilaprevir(c)

Glecaprevir(a)

Grazoprevir(b)

Voxilaprevir(c)

Glecaprevir(a)

Voxilaprevir(c)

NS5A

Daclatasvir(d)

Elbasvir(b)

Ledipasvir(e)

Pibrentasvir(a)

Velpatasvir(c,f)

Daclatasvir(d)

Elbasvir(b)

Ledipasvir(e)

Pibrentasvir(a)

Velpatasvir(c,e)

Daclatasvir(d)

Pibrentasvir(a)

Velpatasvir(c,e)

NS5B

Sofosbuvir(c,e,f,g)

Sofosbuvir(c,e,f,g)

Sofosbuvir(c,f,g)

 

Trade names of DAA:

(a) Mavyret = Glecaprevir + Pibrentasvir

(b) Zepatier = Elbasvir + Grazoprevir

(c) Vosevi = Sofosbuvir + Velpatasvir + Voxilaprevir

(d) Daklinza = Daclatasvir

(e) Harvoni = Ledipasvir + Sofosbuvir

(f) Epclusa = Sofosbuvir + Velpatasvir

(g) Sovaldi = Sofosbuvir

 

Antiviral drug RAS in the relevant HCV genomic regions can be detected and identified genotypically using either Sanger sequencing or next-generation sequencing (NGS) methods. Amino acid changes deemed as RAS are predicted by the NS3, NS5A, and NS5B sequences of the patient's HCV strain by comparing them to the expected amino acid at relevant codon positions within a wild-type HCV reference sequence. DAA drug resistance may be predicted for each drug based on the relevant RAS present in the HCV sequences found in the patient's serum. Prediction of HCV antiviral drug resistance in this NGS assay is based on a combination of FDA-approved prescribing information for the drug and professional society practice guidelines (see Table and www.hcvguidelines.org/evaluate/resistance).

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretive report will be provided.

Interpretation
Provides information to assist in interpretation of the test results

Interpretation of antiviral drug resistance in this assay is based on a detection threshold of 10% of resistance-associated hepatitis C virus (HCV) variants present in the patient's serum specimen (ie, minimum 10% frequency of such variants).

 

This assay will confirm the patient's HCV genotype, with possible genotype results generated as 1a; 1b; 1, no subtype; 2a; 2b; 2, no subtype; 3a; 3, no subtype; 4a; 4, no subtype; 5a; 6a; 6, no subtype. However, analysis of resistance-associated substitutions (RAS) and prediction of antiviral drug resistance are restricted only to HCV genotype test results of 1a, 1b, 3a, or 3 no subtype.

 

Inconclusive result indicates that testing failed, likely due to presence of inhibitory substances in the submitted serum specimen. A new serum specimen should be collected and submitted for retesting if clinically indicated.

 

Indeterminate result is due to presence of atypical HCV genomic sequences, such as a recombinant HCV strain comprised of genomic sequences from multiple genotypes, preventing definitive determination of the HCV genotype.

 

Unable to genotype indicates that the assay is unable to reliably determine antiviral resistance because of either low HCV viral load (ie, <50,000 IU/mL) or ambiguous or incomplete HCV target sequences generated with the assay.

 

Predicted resistance means that the RAS detected have been reported to be associated with reduction in susceptibility to the specific direct-acting antiviral (DAA) drug.

 

Possible resistance means that the RAS detected may be associated with a reduction in susceptibility to the specific DAA drug due to possible cross-resistance within the same drug class. Current peer-reviewed, published reports do not have sufficient data to definitively rule out antiviral resistance to the drug.

 

Not predicted means that no RAS were detected and no resistance to the specific DAA drug is predicted for patient's HCV strain.

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

A patient's response to antiviral therapy depends on multiple factors, including the patient's hepatitis C virus (HCV) genotype, characteristics of the infecting viral strain, patient compliance with the prescribed drug therapy, patient's access to adequate care, drug pharmacokinetics, and drug-drug interactions. Drug-resistance test results should be interpreted only in conjunction with clinical presentation and other laboratory markers when making therapeutic decisions.

 

Absence of resistance to a drug does not rule out the presence of reservoirs of direct-acting antiviral-resistant HCV in the infected patient.

 

An HCV genotypic drug resistance test is not a direct measure of antiviral drug resistance. Although genotypic testing can detect resistance-associated substitutions (RAS) in the relevant HCV genomic regions, the clinical significance of these RAS requires careful interpretation to predict drug susceptibility. This assay's ability to amplify the HCV target sequences and detect RAS may be limited when the serum HCV viral load is less than 50,000 IU/mL due to HCV strain diversity. Serum specimens submitted for this test should contain a minimum of 50,000 IU/mL of HCV RNA.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Pawlotsky JM: Hepatitis C virus resistance to direct-acting antiviral drugs in interferon-free regimens. Gastroenterology. 2016 Jul;151(1):70-86. doi: 10.1053/j.gastro.2016.04.003

2. Wyles DL, Luetkemeyer AF: Understanding hepatitis C virus drug resistance: clinical implications for current and future regimens. Top Antivir Med. 2017;25(3):103-109

3. Sorbo MC, Cento V, Di Maio VC, et al: Hepatitis C virus drug resistance associated substitutions and their clinical relevance: Update 2018. Drug Resist Updat. 2018 Mar;37:17-39. doi: 10.1016/j.drup.2018.01.004

4. Wyles DL: Resistance to DAAs: When to look and when it matters. Curr HIV/AIDS Rep. 2017 Dec;14(6):229-237. doi: 10.1007/s11904-017-0369-5

5. European Association for the Study of the Liver: EASL recommendations on treatment of hepatitis C 2018. J Hepatol. 2018 Aug;69(2):461-511. doi: 10.1016/j.jhep.2018.03.026

6. American Association for the Study of Liver Diseases and the Infectious Diseases Society of America: HCV guidance: recommendations for testing, managing, and treating hepatitis C. HCV resistance primer. Updated October 5, 2021. Accessed September 7, 2022. Available at: www.hcvguidelines.org/evaluate/resistance

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Description
Describes how the test is performed and provides a method-specific reference

This test utilizes the commercially available Sentosa SQ HCV Genotyping Assay, v 2.0, a next-generation sequencing assay based on a "sequencing by synthesis" method. The assay is designed to specifically amplify 4 sequences ranging from 600 to 1100 base pairs in length, located in 3 different nonstructural (NS) regions of the hepatitis C virus (HCV) genome: NS3 (67 RAS at 15 codon positions), NS5A (52 RAS at 13 codon positions), and NS5B (7 RAS at 4 codon positions). Clinical serum specimens are subjected to automated HCV RNA extraction and purification, followed by reverse-transcription polymerase chain reaction (RT-PCR) 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 (PGM) 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: Sentosa SQ HCV Genotyping Assay v2.0 (4x16), Version 1.1. Vela Operations; no. PS103375D, 2020).

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Friday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

4 to 14 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

60 Days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

87900

87902

87522 (if appropriate)

LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
HCVDR HCV Genotypic Drug Resistance, S 82525-7
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
604410 HCV Genotypic Drug Resistance, S 77202-0
604376 HCV Genotype 92731-9
604377 HCV NS3 RAS 73654-6
604378 Sequence failure at codons: 92732-7
604379 Glecaprevir resistance 92733-5
604380 Grazoprevir resistance 82523-2
604382 Voxilaprevir resistance 92734-3
604383 HCV NS5A RAS 73655-3
604384 Sequence failure at codons: 92732-7
604385 Daclatasvir resistance 82379-9
604386 Elbasvir resistance 82376-5
604387 Ledipasvir resistance 82377-3
604388 Pibrentasvir resistance 92735-0
604389 Velpatasvir resistance 82520-8
604390 HCV NS5B RAS 73655-3
604391 Sequence failure at codons: 92732-7
604392 Sofosbuvir resistance 82382-3
604393 HCV Genotype 92731-9
604394 HCV NS3 RAS 73654-6
604395 Sequence failure at codons: 92732-7
604396 Glecaprevir resistance 92733-5
604397 Grazoprevir resistance 82523-2
604399 Voxilaprevir resistance 92734-3
604400 HCV NS5A RAS 73655-3
604401 Sequence failure at codons: 92732-7
604402 Daclatasvir resistance 82379-9
604403 Elbasvir resistance 82376-5
604404 Ledipasvir resistance 82377-3
604405 Pibrentasvir resistance 92735-0
604406 Velpatasvir resistance 82520-8
604407 HCV NS5B RAS 73655-3
604408 Sequence failure at codons: 92732-7
604409 Sofosbuvir resistance 82382-3
HCVKG Is known HCV genotype 1a, 1b, or 3? 86955-2
HCVLR HCV RNA level IU/mL last 30 days = 86955-2

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports

Test Update Resources

Change Type Effective Date
Test Status - Test Resumed 2022-09-16
Test Status - Test Delay 2022-08-26
Test Status - Test Resumed 2022-06-07