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Test ID: HCVQG Hepatitis C Virus (HCV) RNA Quantification with Reflex to HCV Genotype, Serum


Advisory Information


For detection and quantification of hepatitis C (HCV) RNA and genotype in serum before initiating antiviral therapy for chronic hepatitis C.

 

Do not order this test to monitor response and progress during antiviral therapy for chronic hepatitis C.



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° C (up to 42 days) until shipment on dry ice.



Specimen Required


Supplies: Aliquot Tube, 5 mL (T465)

Collection Container/Tube: Serum gel

Submission Container/Tube: Polypropylene vial (T465)

Specimen Volume: 3.5 mL

Collection Instructions:

1. Centrifuge blood collection tube per collection tube manufacturer's instructions.

2. Pour off serum into aliquot tube.


Useful For

Detection of acute HCV infection before the appearance of HCV antibodies in serum (ie, <2 months from exposure)

 

Detection and confirmation of chronic HCV infection, and determining HCV genotype (1 to 5) to guide antiviral therapy in patients with chronic hepatitis C

 

Quantification of HCV RNA in serum of patients with chronic HCV infection (HCV antibody-positive) before initiating antiviral therapy

 

Determining cure and detection of relapse of HCV infection after completion of antiviral therapy

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
HCVG HCV Genotype, S Yes No
HCVGR HCV Genotype Resolution, S No No

Method Name

HCVQG: Real-Time Reverse Transcription-Polymerase Chain Reaction (RT-PCR)

HCVGR: RT-PCR followed by Hybridization with Sequence-Specific, Fluorescent-Labeled Oligonucleotide Probes

Reporting Name

HCV RNA Detect/Quant Reflex Geno, S

Specimen Type

Serum SST

Specimen Minimum Volume

1.6 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum SST Frozen (preferred) 42 days
  Refrigerated  72 hours

Clinical Information

Of all individuals infected with hepatitis C virus (HCV), about 75% of them will develop chronic hepatitis C, with ongoing viral replication in the liver and detectable HCV RNA in serum or plasma, eventually resulting in cirrhosis. The remaining 25% of the infected individuals recover from the infection without evidence of viral replication or the presence of detectable HCV RNA in serum or plasma. Chronic HCV infection can be cured at variable success rates with either combined interferon-alpha and ribavirin therapy or interferon-free combination of direct-acting antiviral (DAA) agents.

 

The antiviral response rates correlate with pretreatment serum or plasma HCV RNA levels (viral load) and the HCV genotype found in the infected individuals. The optimal duration of combined interferon and ribavirin therapy can be determined from the patient's pretreatment viral load and HCV genotype. Clinical trial studies indicated that a decrease in HCV RNA levels of more than 2 log IU/mL at 4 weeks or 12 weeks of therapy is predictive of an increased chance of achieving a sustained virologic response (defined as undetectable HCV RNA levels in serum 6 months after completing antiviral therapy). Despite receiving longer duration of antiviral therapy (48 weeks versus 24 weeks), patients with chronic infection due to HCV genotypes 1 and 4 generally have less favorable sustained virologic response rates (40%-50%) than those infected with genotypes 2 and 3 (>80%). Due to the necessary prolonged duration (typically 24 to 48 week duration) and low cure rates of such antiviral therapy, interferon-based therapy has been supplanted with potent interferon-free DAA combination therapy now.

 

Unique nucleotide sequences of certain regions (eg, 5'-noncoding, core, NS5b) of the 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. HCV genotype determination is important for proper selection of antiviral therapy and optimal patient management.

 

Therapeutic response rates for chronic HCV infection have improved significantly (cure rates of >90%) over the past 5 years when oral DAA agents are used in lieu of interferon-based 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 for simeprevir-treated patients.

 

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/full-report-view.

Reference Values

Undetected

Interpretation

This assay has a result range of 15 to 100,000,000 IU/mL (1.18 log to 8.00 log IU/mL) for quantification of hepatitis C virus (HCV) RNA in serum. Only those specimens with HCV RNA levels of greater than or equal to 500 IU/mL will be tested for HCV genotype (HCVG / Hepatitis C Virus Genotype, Serum or HCVGR / Hepatitis C Virus Genotype Resolution, Serum).

 

An "Undetected" result indicates that the HCV is absent in the patient's serum specimen. Such specimens will not be tested for HCV genotype.

 

A result of "<15 IU/mL (<1.18 log IU/mL)" indicates that HCV RNA is detected, but the HCV RNA level present cannot be quantified accurately below this lower limit of quantification of this assay. Such specimens will not be tested for HCV genotype.

 

A result of ">100,000,000 IU/mL (>8.00 log IU/mL)" indicates the presence of active HCV viral replication, and the HCV RNA level present cannot be quantified accurately above this upper limit of quantification of this assay.

 

An "Inconclusive" result reported with a comment indicates that testing failed, likely due to presence of inhibitory substances in the submitted serum specimen. A new specimen should be collected for retesting. Such specimens will not be tested for HCV genotype.

Clinical Reference

1. de Leuw P, Sarrazin C, Zeuzem S: How to use virological tools for the optimal management of chronic hepatitis C. Liver Int 2011;31 Suppl 1:3-12

2. Centers for Disease Control and Prevention: Testing for HCV infection: an update of guidance for clinicians and laboratorians. MMWR Morb Mortal Wkly Rep 2013;62(18):362-365

3. American Association for the Study of Liver Diseases and Infectious Diseases Society of America: HCV guidance: Recommendations for testing, managing, and treating hepatitis C. Accessed July 14, 2017 Available at www.hcvguidelines.org/full-report-view

Day(s) and Time(s) Performed

Monday through Saturday; 7 a.m.-4 p.m.

Analytic Time

Monday through Saturday, 1 day; Friday, Saturday, 3 days

Test Classification

This test has been cleared, approved or is exempt by the U.S. 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

87522

LOINC Code Information

Test ID Test Order Name Order LOINC Value
HCVQG HCV RNA Detect/Quant Reflex Geno, S 11011-4

 

Result ID Test Result Name Result LOINC Value
603602 HCV RNA Detect/Quant, S 11011-4

Forms

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

Mayo Clinic Laboratories | Gastroenterology Catalog Additional Information:

mml-gi-liver-hepatitis