What is the purpose of a Double Marker Test?

A series of tests is conducted during the pregnancy journey, to rule out any medical condition or abnormality in the fetus and to also monitor the health of the mother and the baby. To ensure that the fetus does not have any chromosomal disease, one such test is prescribed which is known as dual marker test.
Let’s try to understand the procedure, and purpose of the test and its results. 
What is a Double Marker Test?
Conducted in the first trimester of the pregnancy, the double marker test is used to identify the risks of chromosomal abnormalities in the fetus.
The level of Beta-hCG (beta-human chorionic gonadotropin) & PAPP-A (Pregnancy-Associated Plasma Protein A) is measured by the dual marker test. Risk of chromosomal abnormalities like Down Syndrome & Edward’s syndrome is depicted by the altered presence of these markers in the blood sample of the pregnant woman.

Dual marker test is usually advised to a woman who is above 35 years or for couples who have a family history of chromosomal abnormalities. It is not a mandate test during the pregnancy journey.

The Doctor usually prescribes diagnostic tests after the screening test confirms the abnormalities. Dual marker is only a predictive test and does not confirm the disease in the fetus.

What are Chromosomal Abnormalities?
The irregularities in the number of chromosomes in the fetus DNA that cause the chromosomal abnormality is detected by the dual marker test.
A male fetus, 22 pairs of autosomes and a pair of XY chromosomes however a female fetus is supposed to have 22 pairs of autosomes and a pair of XX chromosomes and . The chromosomal abnormality can have a division as given below: 
Patau’s Syndrome: An extra copy of chromosome 13, it is also known as Trisomy 13
Edward’s Syndrome: Edward’s Syndrome is also widely known as Trisomy 18 

An extra copy of chromosome 18 depicts Edwards’s Syndrome.

Down’s Syndrome: A duplication of the 21st chromosome, also known as Trisomy 21

Procedure for the Double Marker Test.
The test is usually performed  between weeks 11-14 weeks in the first trimester
The double marker test depicts the beta-hCG and PAPP-A in the blood. The placenta secretes a glycoprotein known as Beta hCG. In case that there is a rise in the level of the hormone, that indicates the risk of Down Syndrome on the other hand PAPP-A is a plasma protein and a lower level of this hormone is also associated with Down Syndrome. 

Double marker test consists of a blood test and an ultrasound called nuchal translucency (NT) scan. 
Real-time images of the fetus are collected to get a clear area at the back of the fetus’s neck with the help of NT Scan. It determines the fluid collection at the back of the neck, more fluid is a clear indication of Down Syndrome.

The clear understanding of the potential risks of chromosomal abnormalities in the development of a fetus, is derived through the Double Marker Test. 

 Understanding the results of a Double Marker Tests. 

The result falls into three categories: low risk, moderate risk and high risk.

Low risk indicates a very low risk of chromosomal abnormalities in the fetus. In the case that the result shows a moderate or a high risk of abnormalities, doctors may suggest to go for further tests like NIPT 
(Non-Invasive Prenatal Testing), Aminocentesis, 
The results of the dual marker test can fall into any of three categories: low-risk, moderate-risk, and high-risk or chorionic villous sampling; these tests can further confirm the presence of any chromosomal abnormality in the fetus. 

 Usually the TAT of getting the result of a double marker test lies between 3-7 days.

The test offers crucial insights into the fetus’s health. To avoid any future complications the pregnant mothers must sincerely consider taking the double marker test.

In case that you are booking for a diagnostic lab in Zambia that provides Double marker test. You can book it with Sanket Diagnostics for accurate screening.