Pathology Handbook

IL 28B Genotype


IL28B polymorphisms

Clinical Indications

A genetic polymorphism in the IL28B gene (encoding interferon-g-3), is associated with variation in response ofchronic hepatitis C virus to treatment with peginterferon-a-2b and ribavirin. The CC genotype has been associated with greater rate of sustained virological response than the TT genotype, in a number of different ethnic groups.

Further information is available in the following article: Nature, 2009, Vol 461, Pages 399-401

Request Form 

Request on ICE


Analysed by referral laboratory if specific criteria met

Specific Criteria

Please indicate reasons for which the patient is being screened.

Turnaround Time

4 weeks

Patient preparation

This is a genetic test. Please ensure any appropriate genetic counselling is provided to the patient and that the patient has agreed to this test


EDTA whole blood


1-5 ml


Purple top (EDTA) tube

Vacutainer purple top

Lab handling

Sent to referral laboratory (Gartnavel, Glasgow)

Causes for Rejection

Unlabelled or incorrectly labelled sample

Reference Range

Genotype report will be CC or CT or TT and these are reported with the following interpretation:

Genotyping the IL28B marker generates clinically useful information for predicting patient response to combination antiviral therapy (Pegylated Interferon and ribavirin therapy) for chronic Hepatitis C infection. A proportion of CC homozygotes have been shown to have a better response to Pegylated interferon and ribavirin therapy than CT heterozygotes (who have been shown to have an intermediate response) and TT homozygotes (who have been shown to have a poor response). See Ge et al, Nature 2009, p399-401.'