- March 11, 2020
- Michael Allibone
- Posted in Resources
From the moment of conception to the moment of birth, your child's creation is nothing short of a miracle. Yet, along the way, first-time mothers often feel overwhelmed by all of the testing options that are available to them throughout those nine months.
At NTD Eurofins, we hope every soon-to-be mother gets to experience a smooth, uneventful pregnancy and, in the end, gives birth to a healthy, happy baby.
Prenatal screening assessments are valuable tools to help families and physicians successfully manage a pregnancy. However, prenatal screenings are not the same as diagnostic tests – a common misconception.
Here is what you need to know about the difference between prenatal diagnostic and screening tests.
Prenatal Screening v.s. Prenatal Diagnosis
In our modern age, we are extremely lucky to have technology and medicine that are able to remove much of the mystery that once surrounded pregnancy. Today technology offers a variety of ways to test and screen for a wide range of potential medical concerns.
First-time moms will receive a wealth of information during the first trimester and it's easy to feel overwhelmed by all the details. In particular, though, we want to make sure you know what to expect from each diagnostic or screening test, especially since the two are not equal or interchangeable.
What Is a Prenatal Screening Test?
There are several differences between prenatal screening tests and prenatal diagnostic tests, but the main distinction is that screening tests measure risk. Screening tests are non-invasive in nature and are used only to determine the possibility of a particular condition.
Rather than telling you whether or not your growing baby has a specific condition with absolute certainty, screening tests assess whether you are thought to be at high risk for a particular condition and if additional testing is recommended.
Screening tests usually involve a simple blood test or imaging, which are non-invasive and pose no harm to your baby.
Your doctor will determine whether you need a prenatal screening test and for which conditions by considering your health, age, medical history, and ultrasound information, as well as the father's medical history.
Most prenatal screening tests have an accuracy rate of between 80% and 99%. If the screening shows a potential risk, you and your doctor will decide if you should have a diagnostic test done to confirm. Some physicians typically start with screening tests because they are non-invasive and minimize the risk to the mother and baby.
What Is a Diagnostic Test?
Unlike a prenatal screening test, a diagnostic test is used to confirm the existence of a medical condition. Diagnostic tests will tell you and your doctor if, in fact, your baby has the specific condition you've tested for.
Some prenatal diagnostic tests require an invasive procedure that could pose a small risk of miscarriage.
There are two main prenatal diagnostic procedures: amniocentesis and chorionic villus sampling (CVS). Amniocentesis is a process of inserting a needle to withdraw amniotic fluid from the mother's womb. The fluid is then used to analyze the baby's genetic material.
The procedure is usually performed after 15 weeks of pregnancy. An amniocentesis is able to confirm the presence of specific genetic conditions because the test analyzes a sample of the baby's own cells, rather than the mother's blood.
A chorionic villus sampling (CVS) test can be done as early as the 1tth week of pregnancy. CVS uses a sample of the placenta to determine the presence of a variety of genetic conditions in the baby.
Talk to Your Doctor About Prenatal Screening
Thankfully, most pregnancies are uneventful. For those expectant mothers with concerns, screenings are a safe and low-cost way to check for potential issues.
If your screening or your medical history indicates a high likelihood of a problematic condition, your doctor may recommend a diagnostic test.
The more you know about your baby's health as he or she is developing, the better you and your doctor can plan for a healthy pregnancy and delivery. Knowing the results of prenatal screening tests can also reduce your anxiety or worries, giving you a better overall pregnancy experience.
Expectant mothers should always consult their physician for advice specific to their pregnancy.
Before heading into your next OB visit, take a look at our Testing Timeline to find out which prenatal tests are available at various stages of your pregnancy.
Have questions? Drop them in the comments below and we'll do our best to help you find the answers.
- What to Expect. (2019). The Difference Between a Prenatal Screening and a Diagnostic Test. Everyday Health Group. https://www.whattoexpect.com/pregnancy/pregnancy-health/difference-between-prenatal-screening-and-diagnostic-test/
- Mayo Clinic. (2019). Chorionic villus sampling. Mayo Foundation for MEdical Education and Research. https://www.mayoclinic.org/tests-procedures/chorionic-villus-sampling/about/pac-20393533
The information provided represents the general opinions of NTD Eurofins and is not intended to be used as specific advice for any one individual. Individuals should always consult with a physician to obtain specific advice and to receive answers to any and all questions or concerns related to health, wellness, pregnancy, and birth.
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Pursuant to applicable federal and/or state laboratory requirements, Eurofins NTD, LLC has established and verified the accuracy and precision of its testing services. Tests are developed and performance characteristics determined by Eurofins NTD, LLC. The methods and performance characteristics have been reviewed and approved by the New York State Department of Health.