Our Tests


The SRY gene is a key determinant of the development of male physical characteristics in the fetus. It is usually located on the Y chromosome. Abnormalities of gender differentiation can be due to deletion or mislocation of this gene. The test provides diagnostic information.

Clinical Utility

In an affected person, an abnormal result usually provides a genetic diagnosis and the basis for genetic counselling. Further family studies may clarify the recurrence risk in relatives.

A normal result does not exclude a genetic or heritable basis for the disorder as a number of other genes can be involved in abnormalities of gender differentiation.



Test Method

Analysis for the presence and chromosomal location of the gene by fluorescent in situ hybridisation (FISH).

Test Ordering

This test is usually requested by a paediatrician or clinical geneticist. A full karyotype is usually requested at the same time.

2-5 mL blood in lithium heparin. 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.

Special Instructions

Please note on the request form whether the requirements of the MBS item descriptor have been satisfied. If this information is not provided, the patient will be billed as a private patient and a Medicare rebate will not be available.



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

Medicare Rebate

This test has a Medicare rebate of $196.35, subject to the requirements of the Medicare descriptor being met. The MBS item number is 73291.

Turnaround Time

15 working days for karyotype and FISH study; 3 working days for FISH alone.