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HCV Genotyping
Test code(s) 37811


Question 1. Which HCV genotypes may be reported by the LiPA assay?

The LiPA genotype assay can detect all 6 major HCV genotypes (1–6) and many HCV subtypes, including 1a, 1b, 2a-c, 3a, 3b, 3c, 3k, 4a/c/d, 4f, 4h, 5a, 6a/b and 6c-l. If the banding pattern does not sufficiently differentiate between subtypes within a genotype, only the genotype may be reported, for example "genotype 1" or "genotype 2".

Question 2. The HCV genotype test result is “we were unable to obtain an HCV genotype,” but the patient has a detectable viral load. Why was there no genotype result?

The LiPA genotype assay usually requires a minimum viral load of 300 IU/mL to obtain a genotype. Since many of our viral load assays have a much lower limit of quantitation, it is possible for the patient to have a detectable viral load (below 300 IU/mL) and no genotype result.

Question 3. The test result is "1a" with a comment stating "we cannot rule out 6 subtypes c-I." Does that mean the patient is coinfected?

Not necessarily. The HCV genotype assay is performed by analyzing banding patterns that are indicative of the genotype. Two regions of the genome are assessed: the 5' UTR and the core region. Genotype 6 subtypes c-l have the same banding pattern as genotype 1. Therefore, the core region is used to differentiate type 1 from type 6. If the core region banding pattern is not conclusive, we report a type 1 but cannot rule out type 6 subtypes c-l.

Question 4. What is the interpretation of the following LiPA test result: “Hybridization pattern is consistent with the following genotypes: 1a and 2b?”

This indicates that banding patterns indicative of both HCV subtypes 1a and 2b were present. This test result is consistent with HCV coinfection.

Question 5.

How does the LiPA genotype test differ from the HCV NS3a, NS5a, or NS5b genotypic tests for drug resistance?

The LiPA genotype test is designed to detect all 6 major HCV genotypes. The NS3a, NS5a, and NS5b genotype tests, on the other hand, detect mutations associated with drug resistance. They are limited to individuals infected with HCV genotype 1 and are not intended for determining HCV subtype. The HCV genotype test should be performed before ordering a drug resistance test.

This FAQ is provided for informational purposes only and is not intended as medical advice. A physician’s test selection and interpretation, diagnosis, and patient management decisions should be based on his/her education, clinical expertise, and assessment of the patient.
Document FAQS.21 Version: 1
Version 1 effective 10/2/2015 to present
Version 0 effective 01/24/2012 to 10/01/2015