What is carrier status screening?

Genetic carrier screening is a test that can be either a blood test or a saliva test. Genetic carrier screening allows you to understand the chance of passing on an inherited condition to your children.

It lets you consider different options, like:

• using IVF to get pregnant
• having diagnostic testing during pregnancy

What is a genetic carrier?

Most people carry faulty genes that can potentially cause health problems for your child. Genes are instructions that tell our bodies how to develop and work. You have 2 copies of each gene.

If you have one working copy of a gene and one faulty copy of a gene you are known as a carrier. This means that:

• you won’t have the health problem yourself
• you can pass on your copy of the faulty gene to any children you have

If you and your reproductive partner are both carriers for the same condition:

• every child you conceive will have a 1 in 4 chance of being born with the condition
• every child you have will have a 1 in 2 chance of being a carrier

Are there different types of carrier screening?

There are 3 different screening options available:

1. single condition screening — which screens for one specific genetic condition
2. 3 condition screening — which screens for cystic fibrosis (CF), spinal muscular atrophy (SMA) and fragile X syndrome (FXS)
3. expanded carrier screening — which screens for hundreds of inherited conditions

Research shows that 1 in 20 people in Australia carry the gene for:

• cystic fibrosis
• spinal muscular atrophy
• fragile X syndrome

As of 1 November 2023, 34 Medicare rebates for genetic testing have been added. The new rebates are expected to help people find out their combined chance of having a child with genetic conditions, including cystic fibrosis, spinal muscular atrophy or fragile X syndrome. These new rebates are available to everyone, even without a personal history of symptoms or family history of these conditions.

Who should have carrier status screening?

The Australian Guidelines recommend that the following people are offered carrier screening:

• people planning a family
• people in their first trimester of pregnancy

It doesn’t mean that you have to have the test — but you can discuss it with your doctor.

Is genetic carrier screening right for me?

There are hundreds of conditions that are caused by genetic issues. It’s very rare for you and your reproductive partner to both carry the genes that cause health problems.

Genetic carrier screening allows you to be aware that there’s a chance of having a baby with a health condition.

However, genetic carrier screening does not pick up every health condition. It doesn’t guarantee that you will have a healthy baby.

Genetic carrier screening does not replace tests that can be done during pregnancy such as:

• non-invasive prenatal testing (NIPT)
• combined first trimester screening (CFTS)

Non-invasive prenatal testing and combined first trimester screening are usually done in the first 12 weeks of pregnancy.

It’s a good idea to talk to your doctor about the pros and cons of carrier status screening. Only you can decide whether you want to go ahead.

How can I arrange genetic carrier screening?

Genetic carrier screening can be requested by your:

• doctor
• obstetrician
• genetic counsellor

They will fill out a test request form that you take to your local pathology collection centre.

The healthcare provider who orders your tests will tell you which conditions are being screened for.

Make sure you tell your healthcare provider if you have a family history of a genetic condition. This lets them order the most appropriate screening test for you.

The genetic testing will be done in a specialist laboratory.

How much does genetic carrier screening cost?

In Australia, genetic carrier screening can cost from $100 to more than $1,000 depending on the test you have. The actual cost will depend on your provider.

You may be able to claim some money back through Medicare. This will depend on your family history and the tests ordered.

Some private health funds will pay part of the cost if you have a family history of some genetic conditions.

What happens after the screening?

You will normally get your test results back in 2 to 4 weeks.

Genetic carrier screening is usually done before your baby is conceived. If a problem is found, you can look at other ways to get pregnant, such as IVF.

If you’re already pregnant, you can talk to your doctor or a genetic counsellor about the best course of action. This might involve:

• more tests
• the non-invasive pre-natal blood test (NIPT)
• chorionic villus sampling (CVS)
• amniocentesis

My test result was positive

Finding out that your test result was positive may be a shock.

It’s likely that you will have lots of questions about having a baby. A genetic counsellor can give you the information you need to help make your decision.

If you’re found to be a genetic carrier it’s likely that one of your parents is also a genetic carrier. This means that any brothers and sisters that you have may also be a carrier. You may want to share this information with family members.

It’s worth remembering that most people are carriers for 2 severe genetic conditions.

My test result was negative

Genetic carrier screening does not check for all genetic conditions. Unfortunately, a negative test result doesn’t guarantee that your baby will be healthy.

Do I need to have this test every time I have a baby?

No, you only need to have this test once in your lifetime. However, if you are a genetic carrier and have a new partner, they may need to be tested.

Resources and support

If you have any questions or concerns about genetic carrier screening, speak to your doctor, obstetrician or genetic counsellor.