Back to test list

HLA-B5701

Also known as: B5701

Test category:

Immunology - Hypersensitivity; Pharmacogenomic - Hypersensitivity

Use of test

Purpose:

A specific variant of the human leukocyte antigen B57, HLA-B*57:01, is associated with severe cutaneous adverse reactions (SCAR) to the medication, abacavir.

Abacavir must never be prescribed to a patient with HLA*B57:01. Patients must be screened for this variant before being commenced on abacavir.

Utility:

If a person has this variant, the risk of developing a severe cutaneous adverse reaction (SCAR) to abacavir is approximately 99.9%. If a person does not have this specific variant, the risk of SCAR is negligible.

Abacavir must never be prescribed to a patient with HLA*B57:01. Patients must be screened for this before being commenced on abacavir.

Ethical considerations:

This test has a role in identifying patients who may benefit from avoiding a specific drug or dose, but it provides little useful information for people (including relatives) who are not taking the medications of concern. Testing of relatives is generally not recommended.

Methodology:

Analysis of the gene sequence of the HLA-B genes for the presence of this specific variant.

Requesting the test

Ordering:

This test can be requested by any medical practitioner.

Sample required:

4 mL blood in EDTA. Specimens may be collected by the requesting practitioner or at any Sonic Healthcare collection centre (see link below).

To help ensure the quality of the test, a genetic test should be done with a dedicated sample whenever possible i.e. a sample collected specifically for that test rather than a sample that is used for multiple tests.

We recommend that the patient or another adult check the labelling of request forms and sample tubes. 

>Link to Sonic Healthcare collection centres

Turnaround time:

2 business days.

Price:

This test has a Medicare rebate which, subject to the requirements of the Medicare descriptor being met, may cover all or part of the cost.

Rebate:

The Medicare details, including descriptor and schedule fee, are listed under MBS item 73323.