Quadruple Marker Test: Purpose, Risks, Treatment and Results

Aug 29, 2022

Blood tests are standard diagnostic tools that during a pregnancy provide a clear picture of the growth of the foetus and its growth and can also be used to screen for birth defects or other health abnormalities, if any. The quadruple marker test, also known as the maternal serum test, is a blood test that provides useful information about the foetus. It helps estimate if a baby has an increased risk of having down syndrome, trisomy 18, neural tube defects, or abdominal wall defects. The quadruple marker test results help predict the risk of such birth defects. However, it is also important to know that regardless of whether the quadruple marker test shows a low or high risk, it does not mean that the baby has a defect, but only indicated increased chances of the same. The name of the test comes from the fact that it measures the levels of four hormones that are found in all pregnant women’s blood, which are:

• Alpha-fetoprotein (AFP): A protein produced by the developing baby.
• Human Chorionic Gonadotropin: A protein produced the placenta.
• Estriol: Hormone produced by the placenta and baby’s liver.
• Inhibin: Hormone produced by the placenta.

The levels of the above-mentioned substances keep on changing throughout the pregnancy. Hence, it is essential to factor in the phase and stage of the pregnancy in order to accurately diagnose the results to gain information about the growth of the foetus. Performed during the second trimester in a pregnancy, the quadruple marker test poses no risk for the baby, as the blood is drawn from the mother’s vein and sent to a lab for analysis. Based on the stage of the pregnancy, there is another test that is often recommended by healthcare professionals - the double marker test or maternal serum screening. The difference between the quadruple and the double marker test, is mainly that the quadruple marker test is prescribed during the second trimester, and the double marker is prescribed during the first trimester of pregnancy. A double marker test measures the level of free beta HCG and PAPPA-A markers in the blood and helps predict the risk developing complications rather than helping diagnose the risk of abnormalities.

Quadruple MarkerTest Time

In pregnancy, a quadruple marker test is performed during the second trimester which ideally means sometime between 15 weeks and 20 weeks of pregnancy. If an individual has any of the following risk factors, the doctor might recommend them to go for a quadruple marker test:

• Is above the age of 35 or older when the baby is due.
• Has had a viral infection during pregnancy.
• Has a family history of birth defects or congenital disabilities.
• Is diagnosed with type 1 diabetes during pregnancy.
• On harmful medication during pregnancy.
• Has been exposed to high levels of radiation.

What Does Quadruple Test Check?

The quadruple marker test measures four distinct proteins and hormones during pregnancy, hence it is also called the quad test at times. The high and low levels of these proteins and hormones depict the risk of birth defects in the developing foetus and provide useful information to a doctor for them to be able to prescribe further screening, if the need arises. The quadruple marker test measures the following four factors:

• Alpha-Fetoprotein (AFP)
• Estriol
• Human Chorionic Gonadotropin (hCG)
• Inhibin-A

AFP is a protein produced by the baby. Higher levels of AFP could mean that the baby has chances of developing neural tube defects like Spina Bifida or anencephaly. Higher-than-normal levels could also indicate that the pregnancy is farther along than anticipated, or that the individual may be carrying twins. Low levels of AFP on the other hand may indicate a higher risk of having a baby with Down’s syndrome.

Estriol is a hormone produced by the baby and the placenta, which is the structure that provides necessary nutrients to the developing baby. A low level of Estriol indicates a high chance of having a baby with Down’s syndrome.

The hCG is a hormone made by the placenta. Levels that are higher than normal mean an increased risk of having a baby with Down’s syndrome.

Inhibin-A is a protein produced by the ovaries and the placenta. High levels of Inhibin-A indicate greater chances of developing a baby with Down’s syndrome.

During the course of pregnancy, the levels of the above-mentioned proteins and hormones keep changing and alert the doctor about possible genetic disorders in the baby. It must be noted that the quadruple marker screening test report does not mean that the baby has any birth defects. It only means that the risk of developing one is higher.

Quadruple Marker Test Results Explained

A quad screening is a routine test that poses no risk to the development of the foetus and the results allow the doctor to prescribe further screening if required.

Quadruple Marker Test Normal Report

A normal quad screen result means that the individual doesn’t have an increased risk of having a baby with birth defects. The healthcare provider may or may not recommend further screening tests depending on the development of the foetus and other factors.

Quadruple Marker Test Abnormal Report

Abnormal levels of certain hormones and proteins in the quad screening test do not ascertain that a baby may be suffering from neural tube defects or Down’s syndrome. A quadruple marker test for pregnant women, allows doctors to suggest further tests to provide useful information about associated risks and finalise a diagnosis.