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.
Specimens generating indeterminate, genotype 1 without subtype, or mixed genotypes containing genotype 1 without subtype results will be automatically evaluated by genotype resolution at an additional charge.
The following algorithms are available:
-Chronic Hepatitis C Treatment and Monitoring Algorithm: Direct Antiviral Antigen (DAA) Combination
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.
Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test
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.
Specimens generating indeterminate, genotype 1 without subtype, or mixed genotypes containing genotype 1 without subtype results will be automatically evaluated by genotype resolution at an additional charge.
The following algorithms are available:
-Chronic Hepatitis C Treatment and Monitoring Algorithm: Direct Antiviral Antigen (DAA) Combination
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: 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.
Special Instructions
Library of PDFs including pertinent information and forms related to the test
Forms
If not ordering electronically, complete, print, and send 1 of the following:
-Gastroenterology and Hepatology Test Request (T728)
-Microbiology Test Request (T244)
Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.
1.5 mL
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
| Gross hemolysis | Reject |
| 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) | 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.
Specimens generating indeterminate, genotype 1 without subtype, or mixed genotypes containing genotype 1 without subtype results will be automatically evaluated by genotype resolution at an additional charge.
The following algorithms are available:
-Chronic Hepatitis C Treatment and Monitoring Algorithm: Direct Antiviral Antigen (DAA) Combination
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 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
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 one 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 polymerase chain reaction 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 one 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 can 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(8):3040-3043
2. 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. Updated October 24, 2022. Accessed March 27, 2025. Available at www.hcvguidelines.org
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 insert: RealTime HCV Genotype II. Abbott Molecular Inc; R1, 06/2013)
PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information
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.
Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location
Indicates the location of the laboratory that performs the test
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.
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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.
CPT codes are provided by the performing laboratory.
87902
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 |
|---|---|---|
| HCVG | HCV Genotype, S | 32286-7 |
| 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.
|
|---|---|---|
| 81618 | HCV Genotype, S | 32286-7 |