Test Catalog

Test Id : HCVG

Hepatitis C Virus Genotype, Serum

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

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.

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
HCVGR HCV Genotype Resolution, S No No

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

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

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

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 Genotype, S

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

HCV Genotype, S

HCVG

HCV Genotyping

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

Specimen Type
Describes the specimen type validated for testing

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 degrees C or colder (up to 42 days) until shipment on dry ice.

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

Supplies: Aliquot Tube, 5 mL (T465)

Collection Container/Tube: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 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.

Additional Information:

1. Specimens should contain a recommended minimum hepatitis C virus (HCV) viral load of 500 IU/mL.

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.

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

Forms

If not ordering electronically, complete, print, and send a Gastroenterology and Hepatology Client Test Request (T728) with the specimen.

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

1.5 mL

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

Gross hemolysis OK
Gross lipemia 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) 42 days ALIQUOT TUBE
Refrigerated 72 hours ALIQUOT TUBE

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

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.

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

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

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 commonly 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, ledispasvir + 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 (AASLD) and Infectious Disease Society of America (IDSA) recommendations for testing, managing, and treating hepatitis C are available at www.hcvguidelines.org/contents

 

The following algorithms are available in Special Instructions:

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

-Hepatitis C: Testing Algorithm for Screening and Diagnosis

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.

Undetected

Interpretation
Provides information to assist in interpretation of the test results

Hepatitis C virus (HCV) genotyping result

Interpretation

Resolution test (reflex test) ordered?

1a

1a is the definitive subtype/genotype

No

1b

1b is the definitive subtype/genotype

No

2

2 is the definitive genotype

No

3

3 is the definitive genotype

No

4

4 is the definitive genotype

No

5

5 is the definitive genotype

No

1

A definitive genotype/subtype (1a, 1b, 6) could not be assigned. Resolution testing ordered.

Yes

1a, 2 (any 2 genotypes)

Result may be due to mixed genotype infection, recombination of HCV genotypes, or assay probe cross-reactivity.

No

1, 3 (2 genotypes with a 1 no subtype)

Result may be due to mixed genotype infection, recombination of HCV genotypes, or assay probe cross-reactivity. Resolution testing ordered.

Yes

HCV not detected

Assay failed to detect HCV RNA.

No

Indeterminate (undetermined genotype)

HCV RNA detected, but genotype could not be determined. Resolution testing ordered.

Yes

Indeterminate (mix)

Result may be due to mixed genotype infection, recombination of HCV genotypes, or assay probe cross-reactivity.

No

 

An "Undetected" result indicates the absence of detectable hepatitis C virus (HCV) RNA in the specimen.

 

An "Indeterminate" result may be due to 1 or more of the following causes:

1) Low HCV RNA level (ie,<500 IU/mL)

2) HCV genotype 6

3) Probe reactivity with multiple HCV genotypes

4) Variation in patient's HCV target sequences with mismatches to PCR primers and/or probes.

Specimens generating indeterminate results with this assay will be automatically evaluated with the subsequent test HCVGR / Hepatitis C Virus Genotype Resolution, Serum.

 

An HCV genotype result of "1" without a subtype result may be due to 1 or more of the following causes:

1) Low HCV RNA level (ie, <500 IU/mL)

2) Probe reactivity with multiple genotype 1 subtypes

3) Variation in HCV genotype 1 target sequence

4) Misclassification of some true genotype 6 strains

 

This assay is able to differentiate between HCV subtypes 1a and 1b. However, subtypes are not reported for HCV genotypes 2 to 5 due to limitations of the current genotyping assay in accurately differentiating the various subtypes of these genotypes.

 

Results with multiple or mixed HCV genotypes (eg, 1, 5; 1a, 2; or 3, 5) may be due to mixed genotype infection or assay probe cross-reactivity. Only those specimens with multiple or mixed genotype results containing genotype 1 but no subtype will be automatically evaluated with the subsequent test HCVGR / Hepatitis C Virus Genotype Resolution, Serum.

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

An "Undetected" or "Indeterminate" hepatitis C virus (HCV) genotype result does not rule-out active HCV infection. Test results should be correlated with routine serologic and molecular-based testing, as well as clinical presentation. Specimens with indeterminate results will be automatically evaluated with the subsequent test HCVGR / Hepatitis C Virus Genotype Resolution, Serum.

 

Known cross-reactivity between the assay probes and various HCV genotypes limits the ability of this assay to identify multiple HCV genotypes present in a given specimen. Such cross-reactivity or the actual presence of multiple HCV genotypes in the same specimen may result in an "Indeterminate" or multiple/mixed genotype result.

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

1. Germer JJ, Mandrekar JN, Bendel JL, et al: Hepatitis C virus genotypes in clinical specimens tested at a national reference testing laboratory in the United States. J Clin Microbiol. 2011;49:3040-3043

2. American Association for the Study of Liver Diseases and the Infectious Diseases Society of America. Recommendations for testing, managing, and treating hepatitis C. v2020.08. Accessed July 16, 2021. Available at www.hcvguidelines.org/contents

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

Sample Preparation:

The Abbott mSample Preparation System kit is used with the Abbott m2000sp, an automated sample preparation system using the magnetic microparticle processes to extract and purify viral nucleic acids from human serum specimens. An internal control is incorporated in the nucleic acid extraction and purification procedure for processing the assay controls and clinical specimens. After capture of nucleic acids onto magnetic microparticles, the microparticles are washed to remove unbound sample components. Then, the bound nucleic acids are eluted from the microparticles and the eluates are transferred to a 96-well microtiter plate containing polymerase chain reaction (PCR) mastermix reagents for amplification and detection.

 

Amplification, Detection, and Genotyping:

The Abbott RealTime HCV Genotype II assay is used to amplify the 5' noncoding (5' NC), nonstructural 5b (NS5b), and core regions of the hepatitis C virus (HCV) genome, with several PCR primer sets that are optimized to amplify all HCV isolates. An internal control primer set is included to amplify a portion of the hydroxypyruvate reductase gene of the pumpkin plant, Cucurbita pepo. The assays positive control is an armored RNA particle diluted in negative human plasma.

 

During the amplification reaction, complementary DNA (cDNA) sequences are generated from the target RNA sequences by the reverse transcriptase activity of the thermostable rTth DNA polymerase. First, the HCV and internal control reverse primers anneal to their respective target sequences and are extended during a prolonged incubation period. After a denaturation step, in which the temperature of the reaction is raised above the melting point of the double-stranded cDNA:RNA product, a second primer anneals to the cDNA strand and is extended by the DNA polymerase activity of the rTth enzyme to create a double-stranded DNA product. During each round of thermal cycling, amplification products dissociate to single strands at a high temperature, allowing primer annealing and extension as the temperature is lowered. Exponential amplification of the product is achieved through repeated cycling between high and low temperatures, resulting in a billion-fold or greater amplification of target sequences. Fluorescent probes specific for HCV genotypes 1 to 5 and subtypes 1a and 1b anneal to the amplified sequence products in 4 separate reaction wells for each specimen.(Package inserts: RealTime HCV Genotype II. Abbott Molecular Inc; 06/2013)

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.

1 to 6 days

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

2 months

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 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
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.

87902

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