#multiple marker test

Hello mama! Look at you, you’ve come so far. Great job! You must be wondering, quad what? 

Now that you are in your second trimester, your doctor will advise you to go through some more prenatal screening tests. One out of which is triple or quadruple screening. The screening is done to detect the risk for chromosomal abnormalities that can cause birth defects. In India, approximately 1 out of 166 births are affected by birth defects which makes it a major concern and necessary to get screened for birth defects. Birth defects are conditions present from birth. Some birth defects can happen because of the genes passed by parents and some due to the problem with chromosomes. There is a higher risk of birth defects if you are older than 35 years, have a family history of birth defects, have a medical condition of your own like diabetes or obesity, or due to the use of certain drugs or medicine. So, as for now you probably have understood the importance of triple or quadruple screening. Let’s get into some details.

What is a triple or quadruple screen test?

A triple or quadruple test is also known as multiple marker test, extended AFP, AFP Plus. It is a basic blood test done between 15 and 20 weeks of the gestation period to detect the level of different substances in your blood: estriol, human chorionic gonadotropin (hCG), alpha-fetoprotein (AFP), and, in case of a quad screen, inhibin-A.

Estriol is estrogen that comes both from your placenta and the baby while HCG and inhibin-A are made entirely by the placenta. AFP is a protein made by your baby and passes in a small amount from the placenta to your blood. These together determine the potential to develop any birth defects. The test determines your risk of having a child with Down’s Syndrome, trisomy 18, and neural tube defects (spina bifida and anencephaly) 

Wait! I am getting confused. What is the difference between a triple and a quadruple screening?

The only difference between both is that the quad screen is more apt for identifying the risk of Down’s Syndrome and is more accurate than the triple screen test.

How is it done?

Don't you worry! It is a blood test and then the sample is tested for AFP, hCG, estriol, and  Inhibin -A levels. The health professional will

Wrap an elastic band around your upper arm making the targeted vein more accessible. 

Clean the area of the skin where a needle is to be inserted

Put the needle into the vein

Attach a tube to the needle to fill the vial with blood

Remove the band 

Put a cotton ball or gauze pad over the needle site

There is no special instruction or preparation required for the test, so make up your mind and test as soon as you are ready for it.

Okay! So now that the test has been done, how do you interpret the result?

 Well, the best person to tell you about the results is your doctor, leave it on him/her. But still, you can analyze the results on your level. 

A “positive” result means that there is a higher than average chance your baby has a genetic disorder whereas a “negative”  or normal means that your baby probably doesn’t have any genetic disorder.

Low AFP- Indicates risk for neural tube defect

Low AFP, low Estriol, and high HCG level- indicate the possibility for Down’s syndrome

Low level of all markers- Indicates the risk for Edward syndrome.

 If your results are positive, your doctor may want you to take a diagnostic test known as amniocentesis or chorionic villus sampling (CVS). The fluid surrounding your baby in the uterus is collected using a small needle and a sample of cells is withdrawn from your placenta in the tests respectively. Then these samples are cultured in the lab and checked to find any chromosomal abnormality. It is totally up to you whether you want to go for further tests or not. You can talk to a genetic counselor or your doctor about what you should do next. We hope you have a healthy munchkin!

To learn more click here.

REFERENCE

https://www.healthlinkbc.ca/health-topics/ta7038

https://medlineplus.gov/downsyndrome.html

https://medlineplus.gov/lab-tests/alpha-fetoprotein-afp-test/