Quad screen vs. NIPT: Understanding your prenatal screening options

During pregnancy, two of the most common prenatal screening tests your healthcare provider may recommend are the quad screen and non-invasive prenatal testing (NIPT). 

While both give a rough estimate of your child’s risk for having conditions like Down syndrome and trisomy 18, they differ in accuracy, turnaround time, and the method they use to process your results.

You might wonder if you need one test or both and whether the results will give you clarity or raise more questions. This article breaks down everything you need to know about quad screen vs. NIPT, including how they compare, what to expect from your results, and what your next steps might be. 

What is a quad screen?

A quad screen is a test offered during pregnancy to help estimate your baby’s risk for certain genetic conditions and congenital disabilities. It’s called a quad screen because it measures four key pregnancy-related hormones and proteins in your blood:

1. AFP (Alpha-fetoprotein): A protein produced by your baby’s liver

2. hCG (Human chorionic gonadotropin): A hormone made by the placenta

3. Estriol: A form of estrogen produced by the baby and placenta

4. Inhibin A: A hormone that helps regulate pregnancy

To do the test, you’ll provide a blood sample from your arm, which is then analyzed in a lab. The test looks at your hormone levels to determine your baby’s potential risk for:

• Down syndrome (Trisomy 21)

• Edwards syndrome (Trisomy 18)

• Neural tube defects like spina bifida (a condition where the baby’s spine doesn’t fully close) or anencephaly (a severe brain and skull abnormality).

The results are usually labeled as low risk or high risk, but it’s worth noting that this test isn’t diagnostic. Instead, it gives you and your provider more information to decide if further testing might be useful. 

What is non-invasive prenatal testing (NIPT)?

Non-invasive prenatal testing is a screening method used to check whether your baby has certain chromosomal conditions.

Like the quad screen, it starts with a quick blood draw. The sample is then sent to a lab for analysis, where specialists examine cell-free fetal DNA (cfDNA) — fragments of your baby’s DNA that circulate in your bloodstream.

NIPT screens for chromosomal conditions such as:

• Down syndrome (Trisomy 21)

• Edwards syndrome (Trisomy 18)

• Patau syndrome (Trisomy 13)

• Sex chromosome abnormalities (such as Turner or Klinefelter syndrome) 

The results from this test are typically negative (low risk) or positive (higher risk). Still, the keyword is “risk.” NIPT isn’t a diagnostic test — if results indicate a higher risk, your doctor may recommend further testing to confirm the diagnosis.

Bonus — Learn the key differences between a cell-free DNA test and NIPT.

NIPT vs. quad screen: Key differences

While they may seem similar at first, NIPT and the quad screen differ in several important ways, including:

1. The method used to estimate the baby’s risk

2. The genetic conditions they screen for

3. The accuracy of the results

4. The timing of the tests 

5. Result turnaround time

The following sections break these down in more detail to help you better understand which test may be right for you.

1. The method used to estimate the baby’s risk

Source: Edward Jenner

The quad screen estimates your baby’s risk by measuring the levels of four specific hormones and proteins in your blood. These biomarkers (AFP, hCG, estriol, and inhibin A) typically fall within a certain range during pregnancy. Still, as factors like your age, weight, and ethnicity can influence these levels, they’re also factored into the analysis. 

The results are considered normal if your hormone levels are within the expected range for your baby’s gestational age. If they’re too high or too low, this may indicate an increased risk of a genetic condition.

In contrast, NIPT doesn’t measure hormone levels — it examines cfDNA. The test analyzes your baby’s chromosomes for any extra, duplicate, or missing copies. If it detects an imbalance, it indicates a higher risk of a chromosomal condition.

Bonus — Explore these topics to expand your understanding of genetic testing:

• Prenatal genetic testing

• Preconception genetic testing 

• Ashkenazi Jewish genetic testing

• What is carrier screening?

2. The genetic conditions they screen for

While both the quad screen and NIPT estimate your baby's risk for certain genetic conditions, the specific conditions they can detect differ. Here's a breakdown of what each test typically covers:

Both tests can identify common chromosomal conditions like Down syndrome and Edwards syndrome. However, because they use different methods of analysis, their screening capabilities vary. 

NIPT is primarily a chromosomal test, meaning it can detect additional chromosomal conditions that the quad screen can’t. These include sex chromosome abnormalities like Triple X and XXY (Klinefelter) syndrome. Some NIPTs can also determine the baby’s sex.

On the other hand, the quad screen measures alpha-fetoprotein (AFP), a key biomarker that helps identify neural tube defects — something NIPT doesn’t screen for.

[Reddit](https://www.reddit.com/r/BabyBumps/comments/facjnz/comment/fix7vce/?utm_source=share&utm_medium=mweb3x&utm_name=mweb3xcss&utm_term=1&utm_content=share_button)(350)

3. The accuracy of the results

Neither the NIPT nor the quad screen is 100% accurate. This is why some parents have reported receiving false positives or negatives, meaning the results they received didn’t reflect the actual condition of their baby.

That said, studies show that NIPT is generally more accurate than the quad screen, particularly when detecting Down syndrome, with sensitivity often reported to be over 99%. However, its accuracy can vary for conditions like trisomy 18 and trisomy 13.

[Reddit](https://www.reddit.com/r/NIPT/comments/utbtj5/comment/i98szvk/?utm_source=share&utm_medium=mweb3x&utm_name=mweb3xcss&utm_term=1&utm_content=share_button)(260)

Both tests have limitations, and several factors can affect the accuracy of results. The table below outlines reasons why the quad screen and NIPT might not always give a completely accurate risk assessment for your baby:

4. The timing of the tests

Both the quad screen and NIPT have specific timing windows during your pregnancy. Still, you can get an NIPT much earlier than the quad screen.

NIPT is available as soon as your pregnancy reaches the 10th week. By this point, the fetal fraction — the amount of cell-free DNA from the placenta in your blood — typically reaches at least 4%. If it’s lower, the test may not provide reliable results.

The quad screen, however, has a more limited timeframe. It’s typically done between 15 and 22 weeks of pregnancy, meaning you have less time to decide if it’s right for you.

5. Result turnaround time 

When it comes to receiving your results, the quad screen is much quicker. Results are typically available within 2–5 days, depending on the lab. This faster turnaround is especially helpful if you're nearing the recommended testing window and need your results as soon as possible.

NIPT, on the other hand, takes a bit longer — usually 7–10 days — due to the complexity of analyzing fetal DNA. While the wait might feel long, the extended processing time reflects the deeper, more detailed analysis of genetic information, which can provide you with a more accurate risk assessment. Some labs may offer faster processing, but this isn’t always guaranteed. 

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What to do after getting your NIPT and quad screen results

Getting your NIPT or quad screen results can sometimes be confusing, especially if they don’t match your expectations. For example, some parents have reported receiving negative NIPT but a positive quad screen, which left them unsure about what to do next. 

[Reddit](https://www.reddit.com/r/NIPT/comments/1bqr71p/positive_quad_negative_nipt_neg_amnio/)(320)

Since both tests are screenings, not diagnostic tests, discrepancies like this can happen. If you find yourself in this situation, you might wonder whether you should trust the results or pursue further testing.

If your results indicate a low risk, your provider will likely reassure you that no further action is needed. Still, if the results suggest a higher risk, your provider will typically recommend next steps, which may include:

1. Seeking genetic counseling: A genetic counselor can walk you through your results, help you understand their meaning, and discuss your options. This often provides clarity and ensures you make informed decisions.

2. Undergoing a diagnostic test: For a more definitive answer, you may consider diagnostic tests like amniocentesis or chorionic villus sampling (CVS). These are more invasive and come with some risks, so your provider will walk you through the pros and cons to help you decide what’s best for you and the baby. 

Source: Pavel Danilyuk

Ultimately, what you'll do after receiving your results is up to you. Whether you choose further testing, genetic counseling, or to move forward with the information you have, your provider will be there to support and guide you through the process.

Bonus — Learn more about other screening tests:

• Cystic fibrosis carrier screening

• Hemophilia carrier screening 

• First-trimester screening vs. NIPT

• Prenatal genetic testing pros and cons

Quad screening vs. NIPT: Which is the right test for you?

Both quad screening and NIPT estimate the risk of certain conditions, but neither provides a definitive diagnosis. That said, each test has its strengths: NIPT is more accurate and can be done earlier in pregnancy, while quad screening can detect neural tube defects that NIPT does not.

Still, these tests are limited to specific conditions. As you start to think about the bigger picture for your family, it’s important to recognize that many genetic risks are inherited from both parents, often without obvious signs. While NIPT and quad screening focus on specific conditions, they don’t cover the full range of inherited risks that could impact your child’s health.

That’s why many parents opt for a more comprehensive genetic screen, like one Nucleus Family offers. Whether you’re preparing for pregnancy or simply want to make informed health choices, Nucleus provides a comprehensive picture of your genetic health so you can take control of your future.

Navigate family planning with confidence with Nucleus Family

Planning for a family comes with many important decisions — and knowing your genetic health is one of them. Nucleus Family helps you and your partner understand the genetic risks you might pass on to your future children, giving you the information you need to make confident choices. 

Nucleus Family supports you in family planning with:

• Comprehensive insights into genetic risks that could affect your child’s health

• Synced results from both partners for a clear picture of your combined risks

• Easy-to-understand reports that help you make confident, informed decisions

• Non-invasive, at-home testing without visits to clinics or blood tests

• Access to certified genetic counselors to guide you through your results and next steps

• HIPAA-compliant, CAP- and CLIA-certified testing to ensure privacy and accuracy

Whether you’re planning for pregnancy or just want a clearer picture of your genetic health, Nucleus Family empowers you to take the next step with confidence. 

How to get started with Nucleus Family

With Nucleus Family, testing is quick and simple.

Here’s how it works:

1. Sign up for Nucleus Family 

2. Provide your personal details

3. Order your test kit

The kit costs $399 (partner testing, which comes with two kits, costs $798), covering detailed reports and two-way shipping.

After collecting your sample, send it back using the prepaid shipping label. In 6–8 weeks, you’ll learn about your genetic health risks, carrier status, and more.

Feature image source: Mart Production