Are you pregnant? Then let's learn about this Quad Screen test!

Hello! If you are planning to become a mother these days, the most important thing is for both you and your baby to be healthy and well, right? So, you probably know that during pregnancy, various tests are done to check the health of you and your baby. Today we are going to talk about one such very important test, the 'Quad Screen' test, which is done in the second trimester of pregnancy. You may have heard about this. Let's see what it is, why it is done, and how it is done, in simple terms.

What is Quad Screen?

Simply put, the Quad Screen is a blood test done during the second trimester of your pregnancy, between weeks 15 and 20. It mainly checks whether your unborn baby is at risk of developing certain genetic disorders.

Now you might be wondering why it's called a 'Quad'. 'Quad' means four in English. So this test measures the levels of four specific things in your blood. Those four things are:

• AFP (Alpha-fetoprotein): This is a protein produced by the baby's liver.
• HCG (Human Chorionic Gonadotropin): This is a hormone produced by the placenta.
• Estriol: This is another hormone that belongs to the estrogen family and is produced by the fetus and the placenta.
• Inhibin-A: This is a protein produced by both your ovaries and placenta.

The risk is calculated by adding up the levels of these four things and comparing them with several other factors, such as your age and race.

What types of medical conditions are screened with Quad Screen?

Now let's see what this test focuses on. If the levels of the four things mentioned above are lower or higher than normal, it gives doctors a clue that the baby has a chance of developing certain genetic conditions.

There are several main conditions for which this test assesses the risk:

• Trisomy 21: This is what we commonly call Down syndrome . This is a genetic condition that affects intellectual and physical development.
• Trisomy 18: Also known as Edwards syndrome , this is also a serious genetic condition.
• Neural tube defects (NTDs): These are defects in the development of a baby's brain and spinal cord. Examples include conditions such as spina bifida ( a defect in the spine) and anencephaly (a serious defect in the development of the brain).

There is something very important that you must understand here! The Quad Screen is only a screening test. It can never say for sure that your baby definitely has this disease. It only says that there is a certain risk, so more tests may be needed. Strictly speaking, this is not a diagnostic test. Think of it like a weather forecast. Sometimes it says "it will rain," but it definitely doesn't. This is the same with this. So it's best to talk to your doctor about the results without getting too worried.

Do I need to take this test? When exactly is it done?

You may be thinking, "Oh, do I really have to do this?" Actually, getting a Quad Screen is not mandatory. It's optional. You can choose not to have this test.

However, doctors often advise that all pregnant women should undergo this test. Because if a risk is identified early, it can help to take the necessary steps, prepare mentally, or confirm with more specific tests.

This test is done between weeks 15 and 20 of your pregnancy. However, the most accurate results are obtained between weeks 16 and 18. Your doctor will remind you about this and ask you whether you want to have this test or not.

How do you do Quad Screen? Is it safe?

This is a very simple, common procedure. All you have to do is take a small blood sample from a vein in your arm. Just like you would for a blood test for any other disease. The phlebotomist takes some of your blood and sends it to a laboratory. That's where the levels of the four things mentioned above are measured.

This entire process takes a very short time, about 5 to 10 minutes.

As for safety, this is a very safe test. Aside from the fact that a small amount of blood is drawn, it poses no health risks to you or your unborn baby. So there is no reason to be afraid of this test or think twice about it.

What are the four things that are checked by the Quad Screen? What do they say?

Let's now look in more detail at the four things this test looks at and what we can understand from their levels. This is a bit medically heavy, but I'll explain it to you in simple terms.

1. Alpha-fetoprotein (AFP)

• This is a protein produced by the baby's liver.
• If the AFP level is much higher than normal , it could mean that the baby has a neural tube defect, such as spina bifida or anencephaly . Or the baby could have an abdominal wall anomaly, such as omphalocele or gastroschisis .
• However, this is not the only reason for high AFP levels. It could be that you are a few weeks older than you think (incorrect gestational age), or you may be expecting multiples.
• If AFP levels are lower than normal , it may indicate a higher risk of Down syndrome.

2. Unconjugated estriol (UE - Unconjugated estriol)

• This is a hormone produced by both the baby and the placenta, the structure that provides oxygen and nutrition to the baby.
• If the level of this hormone is low , it may indicate an increased risk of having a baby with Down syndrome.

3. Human chorionic gonadotropin (hCG)

• This hormone is produced by the placenta. As you may know, the first urine pregnancy test to confirm pregnancy is also the one that looks for this hCG hormone.
• If hCG levels are higher than normal , it may indicate an increased risk of having a baby with Down syndrome.

4. Inhibin-A

• This is a protein produced by both your ovaries and placenta.
• If inhibin-A levels are higher than expected , the risk of having a baby with Down syndrome may increase.

The most important thing to remember is this: If one or more of these tests are abnormal, it does not mean that your baby definitely has a medical condition. It just means that there is a slightly higher risk and that further testing is needed . Your doctor will discuss these results with you in detail and explain what to do next.

How do you understand the test results?

Okay, now let's see how to interpret the results of this test once they come in. The results usually come out as 'low risk' or 'high risk/increased risk'.

Normal/Negative result

• If the Quad Screen result is normal, or 'negative' or 'low risk', it means that the baby has a low risk of developing the genetic conditions mentioned earlier.
• If so, your doctor will likely not recommend additional genetic testing.
• However, a 'normal result' does not mean that the baby will have no complications. This is only a risk assessment test. However, it does mean that the risk is very low.

Abnormal/Positive result

• If the Quad Screen result is 'abnormal', 'positive' or 'high risk', it means that the baby is at a higher than normal risk of having one or more of the conditions mentioned above.
• Again, remember, this does not mean that the baby definitely has the disease. It just means that further testing is needed to confirm.
• If the result is 'high risk', your doctor will suggest a few more tests. These will help you find out for sure whether your baby actually has a genetic defect or not. For example:
• Another detailed ultrasound test. This allows you to see the baby's body structures in detail.
• A test called amniocentesis . This involves taking a very small sample of the amniotic fluid surrounding the baby. This can accurately identify genetic conditions.
• At a time like this, ask your doctor any questions, doubts, or fears you may have and understand them. Ask about the benefits of additional tests and whether there are any risks.

How long does it take for the results to come?

It usually takes about four to five days to get the results of the Quad Screen test. Sometimes it can take up to a week. However, this can vary slightly depending on the lab that performs the test and your doctor's office. You can ask your doctor about the day you will receive the results.

What is the difference between NIPT and Quad Screen?

You may have also heard of a test called NIPT (Noninvasive Prenatal Testing) . This is another test that assesses risks during pregnancy. There are a few key differences between the two:

• NIPT also takes a blood sample from you. However, it analyzes the fetal DNA (deoxyribonucleic acid) in your blood to see if your baby has genetic defects like Down syndrome.
• The Quad Screen looks at the levels of several hormones and proteins in your blood.
• NIPT can usually be done after about 10 weeks of pregnancy. The Quad Screen is done in the second trimester, that is, after 15 weeks.
• NIPT may provide slightly more accurate results (higher detection rate) than Quad Screen for some genetic conditions.
• The important thing is that both of these tests are screening tests only. They are not diagnostic tests. If the risk is shown to be high, a diagnostic test such as amniocentesis will be performed.

You can talk to your doctor about which of these two tests is best for you, or whether you need to have both.

Finally, things to remember (Take-Home Message)

Okay, we've talked a lot about Quad Screen now. I hope this is all clear to you. Finally, here are the most important things you need to remember:

• Quad Screen is a blood test performed during the second trimester of pregnancy to assess the risk of the baby having certain genetic conditions (e.g. Down syndrome, neural tube defects (NTDs).
• This is not a mandatory test, but doctors recommend it. You can talk to your doctor and make the decision that is best for you.
• This is a very safe test. It will not harm you or your baby.
• If the test result is 'positive/high risk', it does not mean that the baby definitely has the disease. It just means that the risk is high and that more specific tests are needed.
• Talk to your doctor about any questions, fears, or doubts you may have. They will explain everything to you and provide you with the support you need.

Becoming a mother is one of the most beautiful, emotional, and hopeful times in life. Being aware of such tests can give you some comfort and peace. Also, if there is any risk, it will be a great help to prepare for it in advance and make the necessary decisions. I wish you and your beloved baby a happy, healthy future!

` Quad Screen, Pregnancy tests, Genetic diseases, Down syndrome, AFP, HCG, Estriol, Inhibin-A, Second trimester, prenatal screening