NOTICE: We are continuing to provide all of our genetic testing during the COVID-19 pandemic, but the reporting times for some of our tests may be slower than usual. This delay could be due to three reasons:
laboratory resources being directed to testing for COVID-19
fewer interstate flights for shipping samples
a backlog of tests as restrictions on elective surgery and procedures are lifted
We apologise for any delay in reporting your genetic test result.
If you have any concerns about this, please speak with the doctor who ordered your genetic test.
Chromosome analysis can detect balanced and unbalanced rearrangements, and numerical changes of autosomes and sex chromosomes.
Once a potential abnormality is identified, chromosome studies of parents may be necessary to clarify the genetic diagnosis and the risks to relatives.
In an affected person, an abnormal result usually provides a genetic diagnosis and the basis for genetic counselling. A normal result does not exclude a genetic or heritable basis for the disorder as sub-microscopic changes would not be detected.
This is an assay for mutations which may be heritable or de novo. It may raise issues of ethics or consent that are different from most other investigations ordered in the routine care of a patient. Use of the consent form (below) is not mandated, but could be used to guide the discussion with the patient.
In the case of carrier testing of an unaffected child, national regulations require that the laboratory has evidence of pre-test counselling by a genetics professional and written consent.
Analysis of metaphase chromosomes by light microscopy. Chromosomes are counted and examined for structural and numerical abnormalities.
Requesting the Test
This test can be requested by any medical practitioner.
2-5 mL blood in lithium heparin. 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.