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  • Writer's pictureShruti GOCHHWAL

Triple Marker Test For Screening Genetic Defects In Unborn Babies

Even before a child is born there is a high chance of them suffering from a range of genetics disorders. Not every child remains safe and healthy inside as well as outside the womb. There are several types of prenatal testing procedures which are there to diagnose such kinds of defects in babies that are yet to come out of their mother’s womb. Detection of such disorders, when the baby is still inside the womb of his or her mother  is crucial for them to attain optimal health in future. Triple marker test is a type of prenatal testing that is used for the same purpose.

This test is very useful in detecting disorders like the Down syndrome, thalassaemia major, neural tube defects, among a variety of others. But there is an issue with regards to this test which needs to be addressed.Many primary care physicians are not yet updated with the right timing of the triple marker test as well as the way to conduct pre and post test counselling.

Triple Marker Test – What Is It?

Triple marker test

Pregnant woman undergoing test, Credit: Canva

It is a blood test that is carried out while the woman is pregnant. The test also consists of triple marker screening. It is essential not to confuse this test with any kind of diagnostic test as it does not provide a diagnosis. It pinpoints any genetic anomalies that the unborn baby is likely to develop. After this test, additional tests need to be conducted in order to diagnose the anomaly that the triple marker test suspected.

Triple marker screening refers to the triple marker test report which also takes in other factors like the pregnant woman’s age, ethnicity, weight, existence of former illnesses, the kind of pregnancy, and the like. This test, apart from pointing to the potential for any genetic anomaly also examines the potential for any chromosomal or birth defects in the yet-to-be born baby. This test should be undergone by women who fall into the following categories:

  1. A history of genetic disorders running in their family

  2. Women who are above 35 years.

  3. And, Women who have been on any kind of medications with side effects

  4. Women who are diabetic or are dependent on insulin

  5. Women who have suffered from a viral infection

  6. Those who have been exposed to radiation before

You must be in your second trimester of pregnancy to undergo this test. It assesses the following hormone’s serum levels:

  1. Alpha-fetoprotein or AFP

  2. Unconjugated estriol

  3. Human chorionic gonadotropin or HCG

Triple marker test cost ranges anywhere between Rs. 1,250 to Rs. 4,200.

How Triple Marker Test Is Done?

Triple marker test procedure

Doctor taking blood test, Credit: Canva

You might think that you need to follow a set of elaborate precautions before undergoing the test. But you need not do so. There is no set time for the test to be carried out. Between 14th to 18th weeks of your pregnancy, the test is conducted anytime. There is also absolutely no risk involved during or after the test procedure. For getting the most effective analysis for any potential birth defects in the fetus, triple marker test results are supplemented with sonography reports of the scan. Sonography is conducted at the beginning of the second trimester.

The test starts with a blood test of the pregnant woman. Its sample is transferred to the hospital lab for examination and assessment. The report of this test is produced within a couple of days after the sample has gone to the laboratory. The test does not cause any kind of adverse side effects in the woman.

How Do You Read a Triple Marker Test?

Triple marker test report

Doctor reading a test report, Credit: Canva

The three markers which this test measures are AFP, estriol, and HCG. Since it measures these three markers, it is called a triple marker test. You can interpret or read the results of the test in the following manner:

  1. The protein AFP is generated by the developing fetus. If its levels are high, it points to a likelihood of neural tube defects in the developing baby. It can also point toward incomplete closure of the abdomen of the fetus.

  2. The hormone HCG is generated by the placenta cells. If its levels are low, it points towards a miscarriage. On the other hand, its high levels signal more than one pregnancy.

  3. The hormone estriol is a form of estrogen and is found in placenta and fetus. Low levels of estriol will signify Down Syndrome in the baby.

What Is the Normal Range of Triple Marker Test?

normal range

Woman taking her test report, Credit: Canva

By now you must have realized the significance of this test and how crucial it is for knowing the health status of your unborn baby. Many people often ask about the normal range of this test so as to interpret it in a better way. Here are the normal values of the three hormones:

  1. The normal value for alpha fetoprotein hormone is 0.20 ng per ml – 250 ng per ml. This is the normal value at 32 weeks of the fetus development.

  2. The normal value for HCG hormone in females is 4,060 to 165400 mlU per ml.

  3. The normal value of the estriol hormone in females in the third trimester is less than 14.60 ng per ml.

What if Triple Marker Test Is Negative?

negative result

Woman concerned with her test report, Credit: Canva

Those parents who find the triple marker test giving them a negative indicator should then decide carefully what their future plan of action should be. A negative triple marker test can be alarming. However, you should always remember  that it is too soon to stress and worry about it. Rather than worrying they should conduct further testing and take all the necessary steps to reduce the likelihood of the baby developing a defect.

Another route of action for the parent can be to order an amniocentesis test. This test is conducted by taking an amniotic fluid sample from the region of the uterus through a hollow and thin needle. The test is effective in the examination of fetal infections and genetic abnormalities.

Thus, with proper examination the likelihood of the fetus developing a genetic defect can be reduced to a great extent.

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