Test ID: HCVG
Hepatitis C Virus Genotype, Serum
NY State Approved 
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Guiding duration of therapy in patients with chronic hepatitis C
Differentiating between hepatitis C virus subtypes 1a and 1b
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
The following algorithms are available in Special Instructions:
-Testing Algorithm for the Diagnosis of Hepatitis C
-Chronic Hepatitis C Standard-of-Care Treatment Algorithm: Combined Pegylated Interferon and Ribavirin Therapy
-Chronic Hepatitis C Treatment Algorithm: HCV Genotype 1 with Telaprevir-containing Combination Therapy
-Chronic Hepatitis C Treatment and Monitoring Algorithm: Boceprevir-Containing Combination Therapy (HCV Genotype 1 only)
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
- Chronic Hepatitis C Standard-of-Care Treatment Algorithm: Combined Pegylated Interferon and Ribavirin Therapy
- Chronic Hepatitis C Treatment Algorithm: HCV Genotype 1 with Telaprevir-Containing Combination Therapy
- Chronic Hepatitis C Treatment and Monitoring Algorithm: Boceprevir-Containing Combination Therapy (HCV Genotype 1 only)
- Testing Algorithm for the Diagnosis of Hepatitis C
Method Name A short description of the method used to perform the test
Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR)
(PCR is utilized pursuant to a license agreement with Roche Diagnostic Systems, Inc.)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
HCVG
HCV Genotyping
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Collection Container/Tube: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 2 mL
Collection Instructions:
1. Spin down and separate serum from gel within 6 hours of collection.
2. Freeze serum immediately and ship specimen frozen on dry ice.
3. If shipment will be delayed for >24 hours, freeze serum at -70 degrees C (up to 35 days) until shipment on dry ice.
Additional Information: Specimens should contain a recommended minimum HCV viral load of 1,000 IU/mL.
Forms: If not ordering electronically, submit a General Request Form (Supply T239) with the specimen.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | Mild OK; Gross OK |
| Lipemia | Mild OK; Gross OK |
| Icterus | NA |
| Other | Heparinized specimen, red top tube, plasma |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum SST | Frozen (preferred) | |
| Refrigerated | 24 hours | |
| Ambient | 6 hours | |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Unique nucleotide sequences of certain regions (ie, 5'-noncoding, core, NS5b) of the hepatitis C virus (HCV) genome allow classification of HCV into 6 major genotypes or clades (1 to 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% to 90%) than genotypes 1 and 4 (40%-50%) to current standard combination therapy (ribavirin plus pegylated interferon alpha-2a or alpha-2b). Duration of current standard 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 combination therapy if early virologic response is achieved.
Therapeutic response rates for HCV genotype 1 infection are improved significantly (70%-80%) when a direct acting antiviral agent (eg, boceprevir, telaprevir) is added to current standard combination therapy. However, antiviral resistance can emerge during such combination therapy, and occurrence of such resistance is more frequent with HCV subtype 1a than 1b.
See Advances in the Laboratory Diagnosis of Hepatitis C (2002) in Publications
The following algorithms are available in Special Instructions:
-Testing Algorithm for the Diagnosis of Hepatitis C
-Chronic Hepatitis C Standard-of-Care Treatment Algorithm: Combined Pegylated Interferon and Ribavirin Therapy
-Chronic Hepatitis C Treatment Algorithm: HCV Genotype 1 with Telaprevir-containing Combination Therapy
-Chronic Hepatitis C Treatment and Monitoring Algorithm: Boceprevir-Containing Combination Therapy (HCV Genotype 1 only)
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
An "Undetected" result indicates the absence of detectable hepatitis C virus (HCV) RNA in the specimen.
An "Indeterminate" result has the possible following causes:
-Low HCV RNA level (ie, <1,000 IU/mL)
-Probe reactivity with multiple HCV genotypes
-Atypical viral target sequence with mismatches to PCR primers and/or probes
A genotype result of "1" without a subtype result indicates the presence of:
-Low HCV RNA level (ie, <1,000 IU/mL)
-Probe reactivity with multiple genotype 1 subtypes
-An atypical genotype 1 viral target sequence
Subtypes are not reported for HCV genotypes 2 to 6 due to limitations of the current genotyping assay in accurately differentiating the various subtypes of these genotypes.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
This assay should NOT be used as a screening test for hepatitis C virus (HCV) infection. It should be requested only on specimens obtained from patients confirmed to be actively infected with HCV.
An "Undetected" or "Indeterminate" 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 containing low HCV viral load (ie, <1,000 IU/mL) may yield "Indeterminate" results.
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" test result.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Ghany MG, Strader DB, Thomas DL, et al: Diagnosis, management, and treatment of hepatitis C: an update. Hepatology 2009;49:1335-1374
2. Ghany MG, Nelson DR, Strader DB, et al: An update on treatment of genotype 1 chronic hepatitis C virus infection: 2011 practice guideline by the American Association for the Study of the Liver Diseases. Hepatology 2011;54:1433-1444
3. 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
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, is used 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 PCR mastermix reagents for amplification and detection.
Amplification, Detection, and Genotyping:
The Abbott RealTime HCV Genotype II RUO assay uses 4 sets of PCR primers. One set of primers targets a sequence within the 5' untranslated region (UTR) of the hepatitis C virus (HCV) genome. This primer set is designed to amplify all HCV isolates. The second primer set is designed to amplify the non-structural (NS) 5b region of genotype 1a. The third HCV primer set is designed to amplify the NS5b region of genotype 1b. An internal control primer set is included to amplify a portion of the hydroxypyruvate reductase gene of the pumpkin plant, Cucurbita pepo. The assay positive control is an Armored RNA particle diluted in negative human plasma. During the amplification reaction, cDNA is generated from the target RNA sequence 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 6 and subtypes 1a and 1b anneal to the amplified sequence products in 3 separate reaction wells for each specimen. Composite results generated from these 3 reaction wells determine the HCV genotype present in a given clinical specimens.(Package insert: Abbott RealTime HCV Genotype II RUO Test, Abbott Molecular Inc., Des Plaines, IL, 8/2010)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Friday; 8 a.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
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 The location of the laboratory that performs the test
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's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
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 Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
87902
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| 81618 | HCV Genotype, S | 32286-7 |
External
link
PDF
document
Excel
document
Word
document