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Microarray (products of conception)

Also known as: SNP array, microarray testing, SNP microarray, CGH microarray, CGH array

Test category:

Reproductive - Miscarriage

Use of test

Purpose:

Microarray analysis can detect submicroscopic deletions and duplications of genetic material across all chromosomes.

Utility:

This test can identify deletions and duplications of chromosome regions and whole chromosomes. This result may identify the likely cause of an episode of pregnancy loss, and may identify a potential cause of recurrent pregnancy loss.

Microarrays can also detect deletions and duplications that are of unknown clinical significance or which have variable clinical outcomes ('susceptibility variants'). 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.

Genetic analysis of products of conception used to be performed by light microscopy (karyotype). Microarray is now the recommended method of analysis; a karyotype can be done on request.

Ethical considerations:

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.

Methodology:

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 singnle nucleotide polymorphism (SNP) microarray, which provides additional genotype information compared with CGH microarray. SNP microrarrays 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

Ordering:

This test is usually requested by an obstetrician or clinical geneticist.

Sample required:

Fresh material in a sterile container. Add sterile tissue culture medium to very small samples.

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

Special instructions:

Please include details of any clinical abnormalities in the patient being tested, and the results of chromosome or array studies in relatives.

Turnaround time:

3-4 weeks.

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.

Note that microarray and karyotype analyses cannot both be rebated on the same test episode

Rebate:

The Medicare details, including descriptor and schedule fee, are listed under MBS item 73293.

Click here for our billing policy.