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HLA-B5701

Also known as: B5701

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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.

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.

Clinical 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.

Genes

HLA-B

Test Method

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

Test Ordering

This test can be requested by any medical practitioner.

5 mL blood in EDTA. Specimens may be collected by the requesting practitioner or at any Sonic Healthcare pathology collection centre.

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

Price

$40.55

This test may have a rebate for all or part of the cost.

Medicare Rebate

This test has a Medicare rebate of $34.50, subject to the requirements of the Medicare descriptor being met. The MBS item number is 73323.

Turnaround Time

2 working days.