Hepatitis C Virus Genotype

Shows which type (genotype) of hepatitis C virus you have. It is usually done once and can help your clinician plan treatment.

AI-verified against cited sources. Awaiting expert reviewAlso called HCV GTLOINC 32286-7

What it is

The hepatitis C virus comes in several genetic types called genotypes, numbered 1 to 7, and each has subtypes shown as letters, such as 1a and 1b. CDC counts 7 genotypes and 67 subtypes. In the US, the most common are 1a, 1b, 2 and 3. This test reads the virus's genetic code in a blood sample to find out which type you have. It can only be done when enough virus (HCV RNA) is in the blood.

Why it matters

Your genotype can help your clinician choose the best treatment plan in some situations. AASLD-IDSA says genotype testing may be considered for people in whom it may change treatment. It is not needed for people who have not been treated before, do not have cirrhosis, and will take a medicine that works against all genotypes (called a pangenotypic regimen). Your genotype does not show how much liver damage you have, and it normally stays the same during an infection.

What can affect your result

Viral load: enough virus must be present for the test to type it
Lab method: some labs report subtypes (such as 1a or 1b) and others report only the main genotype
Mixed infections can give a mixed or unclear result
Where you live or where you were infected: how common each genotype is differs by region
Genotyping needs enough virus in the blood. Mayo Clinic Laboratories' combined test runs genotyping only when HCV RNA is 500 IU/mL or higher, so very low viral loads may not be typed.
Mixed infections or unusual strains can give mixed or indeterminate results. Mayo sends indeterminate results, and mixed results that include genotype 1 without a subtype, for a second resolution test.

A genotype normally stays the same during one infection, so it does not move with treatment.

When to talk to a clinician

Talk with your clinician about how your genotype result fits into your hepatitis C care. Get medical care promptly for yellow skin or eyes, a swollen belly, vomiting blood, black stools or confusion.

Questions you could ask

Does my genotype change which treatment options are open to me?
Do I need genotype testing at all, or are the treatment choices the same for every type?

Questions people ask

Does my genotype tell me how serious my infection is?

No. Genotype is mainly used to help choose treatment. It is not a measure of how much liver damage you have. Your clinician uses other tests, such as liver enzymes, fibrosis scores or imaging, for that.

Why does my report say the genotype could not be determined?

The test needs enough virus in the blood to read its genetic code. A very low viral load, a mixed infection or an unusual strain can make the result unclear. Your clinician can tell you whether a repeat or a different test is useful.

Do I need a genotype test at all?

Not always. AASLD-IDSA says it may be considered when it could change treatment, and it is not needed for some people who have not been treated before and have no cirrhosis. Ask your clinician whether it matters in your case.

Show the science and sources

For clinicians and researchers

HCV genotype is determined by reverse-transcription PCR followed by hybridization with sequence-specific probes (Mayo Clinic Laboratories) or by sequencing. Mayo's combined test (HCVQG) runs genotype only when HCV RNA is 500 IU/mL or higher, and automatically sends indeterminate results, and mixed results that include genotype 1 without a subtype, for genotype resolution. CDC reports 7 genotypes and 67 subtypes, with 1a, 1b, 2 and 3 the most common in the US. AASLD-IDSA states that HCV genotype testing may be considered for those in whom it may alter treatment, and that it is unnecessary for treatment-naive people without cirrhosis who receive pangenotypic direct-acting antiviral regimens. Genotype is separate from drug-resistance testing, which looks for specific changes in the virus. AASLD-IDSA advises testing genotype and subtype if a non-pangenotypic regimen will be prescribed, and recommends genotyping before treatment for people with cirrhosis or past unsuccessful treatment.

LOINC 32286-7 (primary), 92731-9. Specimen: serum-or-plasma.

Sources

Hepatitis C Virus (HCV) RNA Quantification with Reflex to HCV Genotype, Serum (test HCVQG), Mayo Clinic Laboratories
Clinical overview of hepatitis C, CDC
HCV Testing and Linkage to Care, AASLD-IDSA HCV Guidance (2024)

AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.