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.
Also known as: SNP array, microarray testing, SNP microarray, CGH microarray, CGH array
Paediatric - Congenital disorder
Use of test
Microarray analysis can detect submicroscopic deletions and duplications of genetic material across all chromosomes.
In the first instance, this test is for an affected patient and can provide diagnostic and prognostic information. Once a potential abnormality is identified, studies of relatives may be necessary to clarify the genetic diagnosis and the risks to relatives.
The presence of a pathogenic abnormality provides specific diagnostic and prognostic information. Further family studies may clarify the recurrence risk in relatives.
The absence of a pathogenic abnormality does not necessarily exclude a clinical diagnosis.
Microarrays can also detect deletions and duplications that are of unknown clinical significance or which have variable clinical outcomes. Rarely, deletions or duplications which are associated with a clinically significant disorder unrelated to the presentation of the patient may be detected. The report will provide advice regarding the interpretation of such findings.
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.
The relative amounts of genetic material from hundreds of thousands of small regions from all chromosomes are measured. Deviations from the expected values can identify deletions and duplications.
Sonic Genetics uses a single nucleotide polymorphism (SNP) microarray, which provides additional genotype information compared with CGH microarray. SNP microarrays can identify large regions of homozygosity, which may be useful in detecting uniparental disomy or an increased likelihood of a recessive disorder.
Requesting the test
This test can be requested by any medical practitioner.
2-5 mL blood in EDTA or lithium heparin. Specimens may be collected by the requesting practitioner or at any Sonic Healthcare collection centre (see link below).
Buccal swabs are available on request, please contact the laboratory if this method of collection is required.
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.