You may be wondering what the difference is between Reproductive Genetic Carrier Screening (RGS) and Non Invasive Prenatal Testing (NIPT), the information on this page will help you to distinguish one from the other.
RGS vs. NIPT – What’s the difference?
It is important to understand the purpose of Reproductive Genetic Screening (RGS) and Non Invasive Prenatal Testing (NIPT) and what this means for you. On one hand, NIPT screens a fetus for chromosome conditions using fetal DNA in maternal blood. On the other hand, RGS screens adults for inherited genetic conditions that have little or no impact on an adults health, but may be passed on to your children.
Reproductive Genetic Screening (RGS)
Unlike NIPT, RGS is carried out by a saliva or blood test prior to conception or during early pregnancy. This determines the likelihood that you are a carrier of a recessive genetic condition that could be passed on to your child.
It’s important to know that we are all carriers of recessive genetic conditions yet there is often no family history of the conditions we carry. For this reason, all couples or individuals should consider RGS as a child can have genetic condition regardless of their parent’s family history, ethnicity or age. Providing RGS early on gives you time to consider your reproductive options if you have been identified as a carrier.
RGS screens up to 289 inherited genetic conditions and is a one-off test. RANZCOG have recently issued a statement indicating that RGS should be offered to everyone planning a pregnancy or in early pregnancy, irrespective of age, family history or ethnicity.
Non Invasive Prenatal Testing (NIPT)
NIPT screens for the most common chromosome conditions including Down syndrome (trisomy 21), Edward syndrome (trisomy18), Patau syndrome (trisomy13) and sex chromosome aneuploidies – Monosomy X (Turner Syndrome), Triple X syndrome (XXX), Klinefelter syndrome (XXY) or Jacob syndrome (XYY).
NIPT requires a maternal blood test from 10 weeks gestation which will provide a low or high probability of whether the current pregnancy will be affected with a chromosome condition. These conditions are most often caused by a sporadic event at the time of conception and are not usually inherited.
The below table compares the two tests in further detail:
|Screening||Genetic carrier screening on adults for inherited genetic conditions that will have little or no effect on them but may have a significant affect on the health of their children.
Every individual carries up to 3-5 genetic conditions.
|Screening for 3 common chromosome conditions and sex chromosome conditions where there is a gain or loss of an entire chromosome.|
|Family History||Usually there is no known family history of a condition.||These chromosome conditions are usually caused by spontaneous changes rather than inherited changes.|
|Consultation||Consult with Genetic Counsellor.
Tele-consults can be arranged to regional areas.
2 Test options available:
|Consult with RN, Midwife or Genetic Counsellor.
|Timing||Preferable to have screening prior to conception or early in pregnancy (1st trimester).||Screening is done early in pregnancy from 10 weeks.|
Individual or couple.
DNA is tested for genetic mutations known to cause inherited conditions.
Known couples require both be tested at the same time to provide a conclusive result.
|Maternal blood sample screening cell-free DNA for chromosomal aneuploidy.|
|Consult Cost||Consult is free.||Consult is free.|
|Test Cost||Individual $695
|Fixed price $505.|
|Medicare||Medicare rebate may be available for some testing done in Australia. Conditions apply.||No Medicare rebate.|
|Results||TAT – 4-6 weeks from receipt of sample.||With current COVID-19 delays – 5 – 7 working days from receipt of sample.|
Still have questions?
If you still have questions about the difference between RGS and NIPT, please get in touch with one of our Genetic Counsellors by calling 1300 557 226.
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