What is the genetic carrier screening?
Genetic Carrier Screening is a DNA test that helps identify individuals or couples who may be at increased risk of having a child with a serious inherited genetic disorder. This information can support informed reproductive decisions. While more than one in 20 Australians is a carrier of at least one genetic condition, most have no family history of the disorder. This is because these conditions are often rare and follow specific inheritance patterns, such as autosomal recessive or X-linked.
Genetic Carrier Screening (GCS) is particularly useful for detecting the three most common inherited genetic disorders in Australia:
- Cystic Fibrosis (CF)
- Spinal Muscular Atrophy (SMA)
- Fragile X Syndrome (FXS)
Carriers of these conditions typically do not experience symptoms themselves, but they do face an increased chance of passing the disorder on to their children. Testing can help you better understand your risk and guide your reproductive choices.
How does the test work?
Our expert Genomic Diagnostics team will use the DNA from your blood sample to test for the most common inherited genetic changes that cause cystic fibrosis, spinal muscular atrophy and fragile X syndrome.
Genetic testing is the only way to find out whether or not you are a carrier for one of these conditions.
Knowing your carrier status can help you make informed choices. For many people, genetic carrier screening provides peace of mind. For those with a higher risk of having an affected child, it provides the opportunity to consider a range of reproductive options.
About the genetic conditions screened
Cystic fibrosis, spinal muscular atrophy and fragile X syndrome can have devastating effects on life-expectancy and quality of life.
- Cystic fibrosis is the most common inherited disorder in Caucasians.
- Spinal muscular atrophy is the most common genetic cause of mortality in children under two.
- Fragile X syndrome is the most common form of inherited intellectual disability.
We provide genetic counselling free of charge for carrier couples when at least one partner has their test at one of our Healius Pathology network collection centres.
Cystic fibrosis and spinal muscular atrophy are autosomal recessive conditions, which means both parents must be carriers to have an affected child. Fragile X syndrome is an X-linked condition, so only the mother must be a carrier to have an affected child.
Hear from a genetic counsellor
If you and your reproductive partner are found to be a carrier couple for any of these conditions, you have the option of being referred by your clinician to a genetic counsellor to discuss your reproductive options, including:
- natural pregnancy, with or without prenatal diagnosis
- pre-implantation genetic diagnosis (PGD) with in vitro fertilisation (IVF) to test and then transfer embryos that are free of the condition
- the use of a sperm or egg donor
- adoption
Patients' process
Step 1
Your doctor will discuss genetic carrier screening with you and complete a request form.
Step 2
Visit your local Healius Pathology collection centre to have your blood sample taken.
Step 3
Your genetic carrier screen results will be delivered to your doctor within 10 – 14 days*.
If you and your partner are identified as a carrier couple, we will offer free genetic counselling to support you with your next steps.
*from when it reaches the laboratory
FAQ
Genetic carrier screening is testing to identify an increased risk of having children with three of the most common inherited genetic disorders: Cystic fibrosis, spinal muscular atrophy, fragile X syndrome.
One in 20 Australians will be a carrier for at least one of these conditions. Most will not have a family history of the disease. Carriers are usually unaffected by the condition themselves, but have a higher risk of having an affected child.
The Royal Australian and New Zealand College of Obstetricians and Gynaecologists recommends offering carrier screening to all women considering pregnancy or in their first trimester of pregnancy.
Cystic fibrosis, spinal muscular atrophy and fragile X syndrome can have devastating effects on life-expectancy and quality of life.
- Cystic fibrosis is the most common inherited disorder in Caucasians.
- Spinal muscular atrophy is the most common genetic cause of mortality in children under two.
- Fragile X syndrome is the most common form of inherited intellectual disability.
Cystic fibrosis and spinal muscular atrophy are autosomal recessive conditions, which means both parents must be carriers to have an affected child. Fragile X syndrome is an X-linked condition, so only the mother must be a carrier to have an affected child.
The best time to have carrier testing is before pregnancy, if possible. This gives you the widest range of reproductive choices and allows more time to make important decisions. However, testing can still be performed during pregnancy, ideally before 12 weeks.
Genetic carrier screening involves getting a simple blood test at your local Healius Pathology collection centre.
We recommend that the female partner get tested first, followed by the male partner if required for cystic fibrosis or spinal muscular atrophy.
Yes, genetic carrier screening for cystic fibrosis, spinal muscular atrophy and fragile X syndrome is bulk-billed.* It’s available free of charge once per lifetime for:
- patients who are pregnant or planning pregnancy
- reproductive partners of carriers of cystic fibrosis or spinal muscular atrophy.
*Medicare eligibility applies
A carrier is someone who has one gene with a genetic variation and one gene that is unaffected. Carriers are typically symptom-free and do not know that they carry this variation.
Our expert Genomic Diagnostics team will use the DNA from your blood sample to test for the most common genetic changes that cause cystic fibrosis, spinal muscular atrophy and fragile X syndrome.
If both partners are identified as carriers for cystic fibrosis or spinal muscular atrophy, or the female partner is identified as a carrier for fragile X syndrome, they are considered to be a carrier couple.
When the female partner is not identified as a carrier, the couple is considered to have a much lower risk of having an affected child.

Recessive diseases are caused by changes (called genetic variants) in both copies of a person’s genes. Every person has two copies of each gene, one inherited from each parent. A recessive disease occurs when both copies of the same gene have the same variant. Cystic fibrosis is an example of a recessive disease.
When two parents are carriers of the same genetic disease, their children have a 1 in 4 (or 25%) chance of having that disease.

With X-linked conditions, such as fragile X syndrome, only the mother must be a carrier to have an affected child.
Generally, no follow-up testing is suggested for the diseases screened as your carrier status does not change. It is important to understand that no screen is able to identify every carrier of every disease. Speak to your healthcare provider if you have special concerns due to family history or other factors.
If you and your reproductive partner are found to be a carrier couple for any of these conditions, genetic counselling is available. This will provide information about the condition and enable in-depth discussions about your options, whether you are already pregnant or planning to have a child.
DNA can be extracted from all sorts of samples, including blood and saliva. We use blood to get the highest quality DNA for a quick and reliable result. This blood sample collection can be easily added to other routine antenatal blood screening tests that your doctor requests for you.
As well as genetic carrier screening for cystic fibrosis, spinal muscular atrophy and fragile X syndrome, we offer expanded genetic carrier screening that can test for up to hundreds of conditions. The expanded test is not covered by a Medicare rebate. Please see our page.
Why recommend screening to your patients?
Genetic carrier screening helps to inform reproductive decision-making and gives carrier couples (where both partners are carriers for CF or SMA or the female partner is a carrier for FXS) the opportunity to consider a range of reproductive options.
Due to the recessive nature of these conditions, 88% of carriers have no family history.1
When to offer screening
RANZCOG recommends that information on carrier screening be offered to all women planning a pregnancy or in the first trimester of pregnancy.2 This includes screening for CF, FXS and SMA. The genetic carrier screening test can be easily added as part of a patient’s routine antenatal blood screening.
There is global consensus that genetic carrier screening is best performed before pregnancy. This gives your patients the widest range of reproductive choices and more time to make important decisions.
Carrier screening can still be offered in early pregnancy, although options will be more limited and time-sensitive.
The recommended screening pathway is to test the female partner first, followed by the male partner if the female is identified as a carrier for CF or SMA.
Genetic conditions screened
CF, SMA and FXS can have devastating effects on life-expectancy and quality of life. The combined affected pregnancy rate for these disorders is equivalent to the population risk of having a child with Down syndrome.
Accuracy of screening results
Genetic carrier screening tests for the most common genetic changes associated with CF, SMA and FXS.
The assay can detect:
- >95% of cystic fibrosis carriers
- >99% of fragile X carriers
- >95% of spinal muscular atrophy carriers
The tests used for GCS are highly accurate diagnostic tests that reliably identify carriers for these conditions. However, genetic carrier screening cannot identify a small percentage of carriers (1-5%) because some very rare genetic variants cannot be detected by the test.
References
Steps
Step 1
Discuss carrier screening with your patient as recommended by clinical guidelines and provide a request form.
Step 2
Patients attend their collection centre with their signed request form.
Step 3
Results are delivered to you by your preferred method. Genetic counselling is offered for couples who are identified as carriers.
FAQ
As well as genetic carrier screening for cystic fibrosis, spinal muscular atrophy and fragile X syndrome, we offer expanded genetic carrier screening that can test for up to hundreds of conditions. The expanded test is not covered by a Medicare rebate. Please see our page.