Overview

percept™ is an Australian non-invasive prenatal test (NIPT). NIPT is a type of screening test used to identify pregnancies that have an increased chance of a chromosome condition such as Down syndrome, Edwards syndrome, Patau syndrome, other rare trisomies, and partial chromosome deletions and duplications.

percept NIPT includes a routine assessment of all 23 pairs of chromosomes (1-22 + X and Y) and is a comprehensive service available within Australia and New Zealand. percept’s genome-wide (all chromosomes) analysis allows for detection of the broadest range of chromosomal conditions, including rare autosomal trisomies, segmental chromosomal changes (deletions and duplications) and specialised analysis for couples who carry a balanced translocation.

Screening can be performed any time from 10 weeks of pregnancy. All testing is undertaken in our fully accredited genetic laboratories and results are available in 3-5 business days from sample receipt. Your test results are analysed by accredited medical scientists who are trained as specialists in prenatal screening and diagnosis. Pre- and post-test genetic counselling is available through VCGS at no additional cost.

percept™: simple, fast, reliable.

VCGS offers a complete service with percept including pre- and post test genetic counselling, clinical interpretation and ongoing follow-up.

percept™ Australian non invasive prenatal test NIPT

What is this test?

NIPT is an advanced screening test that uses cell-free fetal DNA (cfDNA) found in the maternal blood to identify chromosome conditions found during pregnancy. cfDNA is released from the placenta into the maternal blood stream as part of the growth and development of the baby.

Screening is safe and poses no threat to the pregnancy because it uses a simple blood sample collected from the mother. NIPT is the most accurate prenatal screening test for Down syndrome.

When can I have percept™?
percept is available from 10 weeks of pregnancy (as confirmed by a previous dating scan). There is no upper gestation limit for testing, but the ideal time is between 11-16 weeks. This ensures there is enough time for any follow-up testing that may be required. Discuss with your doctor or genetic counsellor before opting for NIPT later in pregnancy.

percept™ can be performed in 2 ways.
Option 1: percept can be performed as a first line prenatal screening test from 10 weeks. VCGS recommends that patients also consider having the 12-week nuchal translucency ultrasound to check the structural development of the baby.

Option 2: percept can be performed as a second screening test, after having combined first trimester screening (cFTS). If you received a ‘screen positive’ result from cFTS or would like further reassurance, additional screening with percept may help in decision making.

What conditions does this test look for?

percept is a highly accurate screening test used to identify pregnancies at increased chance of Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), Patau syndrome (trisomy 13) or sex chromosome conditions such as Turner syndrome (monosomy X) and Klinefelter syndrome (XXY). The chance of having a child with a chromosome condition increases with maternal age. percept also screens for other rare trisomies and partial chromosome deletions and duplications:

Down syndrome: is the most common chromosomal condition seen in children and adults. It is caused by an extra copy of chromosome 21. People with Down syndrome have some degree of intellectual disability and may have other health and developmental concerns.

Edwards syndrome: is less common than Down syndrome and is caused by an extra chromosome 18. Pregnancies with trisomy 18 usually miscarry and babies that are live born rarely survive beyond a few weeks of life. All babies with Edwards syndrome have significant physical and intellectual problems.

Patau syndrome: is even less common than Down syndrome and Edwards syndrome. It is caused by an extra copy of chromosome 13. Pregnancies with trisomy 13 usually miscarry and babies that are liveborn rarely survive beyond the first few weeks of life. All babies with Patau syndrome have serious health problems.

Sex chromosome conditions: are caused by changes in the number of the X and Y chromosomes present. The X and Y chromosomes determine if a baby will be male or female. Babies with Turner syndrome (monosomy X) are females who have only one X chromosome (X instead of XX). Klinefelter syndrome is not typically associated with miscarriage but can cause some developmental problems and infertility.

Rare autosomal trisomies: are caused by extra copies of chromosomes other than 13, 18 and 21. Whilst rarer than Down syndrome, Edwards syndrome and Patau syndrome, they can be associated with an increased risk of miscarriage and other pregnancy complications. Identifying a rare trisomy can help with monitoring the health of the pregnancy.

Segmental imbalances (partial deletions and duplications from 7-10 Mb in size): are caused by extra or missing pieces of genetic material. percept’s advanced analysis means that the entire fetal genome is examined for these partial chromosome imbalances, which can be associated with serious health concerns for the pregnancy. It is important to know that not all partial deletions and duplications can be detected using percept. However this advanced screening method provides the most comprehensive NIPT currently available. All advanced screening is performed on-site at VCGS.

Examples of additional findings reported to date include known chromosome conditions such as:

  • 2q37 deletion syndrome
  • 3p deletion syndrome
  • 4p deletion (Wolf Hirschhorn) syndrome
  • 5p deletion (Cri du chat) syndrome
  • 11q deletion (Jacobsen) syndrome
  • 17p deletion (Miller-Dieker) syndrome
  • trisomy 9p syndrome
  • tetrasomy 9p syndrome
  • tetrasomy 12p (Pallister Killian) syndrome
  • tetrasomy 18p syndrome

Translocation analysis (known carriers): percept provides a unique service for couples where a parent is known to carry a balanced translocation. Balanced translocations are caused by an exchange (translocation) between two segments of chromosomal material. This change usually has no effect on the carrier parent, however a miscarriage can occur if the pregnancy inherits an unbalanced form of the parental translocation. Some unbalanced translocations are associated with ongoing pregnancies, and if this occurs, the resulting segmental imbalance can be associated with serious health problems in the baby.

Please contact the percept laboratory before proceeding with NIPT, as not all translocations can be screened with high accuracy. Our genetic counsellors are also available to provide advice on the suitability and timing of testing.

How do I arrange a test?

Patients require a specific percept request form signed by their doctor or genetic counsellor.

The blood sample for percept can be collected anytime after 10 weeks gestation (as confirmed by a previous dating scan).

A specific blood tube is required for percept NIPT. Therefore please visit an approved VCGS affiliated collection site. Please download list here (PDF).

No special preparation is required before this test and you do not need to book.

No collection centre near you (Australia or New Zealand)? Then contact us on 1300 11 8247 or email [email protected] and we can organise collection for you.

Frequently asked questions

How does NIPT work?

As a baby grows, the placenta releases small fragments of DNA known as ‘cell-free fetal DNA’ (cfDNA) into the maternal bloodstream. Maternal cell-free DNA is also present in the bloodstream. An advanced technology called ‘massively parallel sequencing’ is able to read the genetic information from both the fetal and maternal DNA.

This genetic information can then be traced to the chromosome it came from. If the pregnancy is affected by a chromosome condition, there will be an increase or decrease in the number of DNA sequence reads for that particular chromosome. For example, if the baby has Down syndrome, (an extra copy of chromosome 21), there will be an increase in the number of sequence reads from chromosome 21.

How does percept™ differ from other NIPT services?

There are a number of NIPT tests available on the market. They differ in price, conditions that are tested for, pre- and post-test services and some technical aspects such as test failure rate.

VCGS is a specialist genetics service with over 30 years experience in prenatal genetics. We are experts in the genetics of pregnancy and our interpretation of the NIPT results is alongside other tests performed during pregnancy, like maternal serum screening and ultrasound. percept is also fully supported by a team of clinical geneticists, genetic counsellors and clinical scientists, who together provide the most comprehensive NIPT interpretation and follow up support service available.

percept generates more sequence reads to produce a result, which increases the accuracy of the test. This also means our test failure rate is significantly reduced (approximately 0.2% of samples) compared to some other providers (up to 5%).

What’s the difference between maternal serum screening and non-invasive prenatal testing (NIPT)? Do I need both?

Having both maternal serum screening (combined first trimester screening) and percept provides the best assessment of the health of the pregnancy because each test provides slightly different information.

NIPT is an advanced screening test (more accurate), but it is also more expensive and is not covered by Medicare or private health insurance. Maternal serum screening is a very good screening test which is less expensive and partially covered by Medicare.

Both tests determine the chance that a baby has Down syndrome or Edwards syndrome. NIPT can also provide information about Patau syndrome and sex chromosome conditions. Maternal serum screening provides additional detail about the chance of pre-eclampsia (a serious condition during pregnancy) or the baby having a neural tube defect like spina bifida (second trimester screening only).

Some women choose to have maternal serum screening as their first test and then follow up with NIPT only if they receive a ‘screen positive’ result. Others choose to have both maternal serum screening and NIPT in combination or in some cases, they choose to only have NIPT. If NIPT has been used as the first test, we generally do not recommend having maternal serum screening as well. We also recommend all women have a 12 week ultrasound scan as this provides information about the structural development of the baby.

How accurate is percept™?

percept is an advanced screening test that is more accurate than maternal serum screening for Down syndrome, Edwards syndrome and Patau syndrome.

The detection rate (which describes how good the test is at identifying a particular condition) for Down syndrome using percept is >99%. This means that if the pregnancy is affected by Down syndrome, it will almost certainly be detected.

While percept is an accurate test, it is not diagnostic. Diagnostic testing is the only way to confirm if a condition is present or to reassure that a pregnancy is not affected.

Conditions screened Detection Rate
Down syndrome (trisomy 21) >99%
Edwards syndrome (trisomy 18) >98%
Patau syndrome (trisomy 13) >98%
Fetal sex Accuracy
Male XY, Female XX >99%

How much does percept™ cost?

percept costs $449 (for Australian patients). Currently, there is no Medicare rebate or private health coverage for any NIPT test.

For New Zealand patients, please contact us on +61 3 9936 6402.

How will I get my results?

percept results are available within 3-5 working days (from the time the sample is received in the laboratory). Results are reported to the referring doctor or genetic counsellor.

What do my results mean?

percept screening results are reported as:

Low risk
Most results will be low risk. This means it is very unlikely the pregnancy is affected by one of the specific conditions screened for. There is always the chance that the result is a ‘false negative’, but this is very rare (1 in 10,000 tests). Low risk does not mean ‘no risk’. Other conditions not identified by NIPT may be present.

High risk
A high risk result does not mean the pregnancy is definitely affected by a particular condition. It means there is an increased chance. There is always a possibility that the screening result was a ‘false positive’ so in order to confirm the result or to reassure the pregnancy is not affected, diagnostic testing will be offered.

No result
percept test failure rates are very low (<0.2%). If no result is given, the laboratory will request a repeat sample for testing at no additional charge to the patient.

What happens if I receive a high risk percept™ result?

Receiving a high risk result does not mean your pregnancy is definitely affected by a particular condition; it means there is an increased chance. In this case, a VCGS genetic counsellor will contact your referring doctor to discuss further testing options, such as diagnostic testing (using a CVS or amniocentesis).

Remember, screening tests do not provide a definitive (yes or no) answer. Diagnostic testing is the only way to confirm the presence of a condition or to reassure a pregnancy is not affected.

Can percept™ be used for twin/IVF/donor pregnancies?

Yes.

In the case of a twin pregnancy, percept can give information about the chance of Down syndrome, Edward syndrome and Patau syndrome. Information about sex chromosome conditions or the sex of the babies is not available for twin pregnancies.

VCGS is the only NIPT provider in Australia to offer screening in triplet pregnancies. Please contact VCGS if you are caring for a triplet pregnancy as some acceptance criteria must be met prior to blood draw.

I wish to speak to a scientist or counsellor about percept™.

If you have more questions about your screening options or are not sure whether percept is right for you, please contact one of our genetic counsellors: +61 3 9936 6402.

How do I pay?

Payment is made by providing credit card details at the time of completing the request slip. The fee is charged to the patient’s credit card prior to the result being released. If the test fails and the patient does not want to proceed with a repeat test, the full fee is reimbursed. If a repeat sample is taken, only the single test fee is charged.