The Double Marker Test Overview
The double marker test is such a diagnostic tool that involves giving blood to be examined for markers of specific chromosomal abnormalities.
As you near the end of your first trimester, you may begin to wonder: What color hair will your child have? Will they resemble you or your spouse? Will they be as fearless as your sister’s kid?
While these details will remain a mystery, for the time being, your OB-GYN may recommend certain tests or screenings to know and understand more about your developing baby, which include their gender.
In this article, we’ll get to know more information on how and when the test is administered, what it looks for, and how much you can presume when you get the results.
What is a Double Marker Test in Pregnancy?
The double marker test, also recognized as maternal serum screening, is a component of the first-trimester screening, which is a much more comprehensive screening. It is not a conclusive test. It is instead categorized as a predictive test, which means that its results indicate the possibility of chromosomal abnormalities.
This procedure aims mainly for free beta-human chorionic gonadotrophin (beta-hCG) and pregnancy-associated plasma protein A levels in the blood (PAPP-A).
In a normal pregnancy, female fetuses will have 22 pairs of XX chromosomes and male fetuses will have 22 pairs of XY chromosomes.
A trisomy is a chromosomal condition characterized by the presence of extra chromosomes, such as that of the following:
Down syndrome is a common trisomy that is also known as trisomy 21 since there is an extra copy of chromosome 21.
Trisomy 18 and trisomy 13 are chromosomal abnormalities in which an extra copy of chromosome 18 (Edward’s syndrome) or chromosome 13 (Patau’s syndrome) is present.
In pregnancy complications with these chromosomal abnormalities, hCG and PAPP-A levels may be higher or lower than “normal.”
Blood levels, on the other hand, do not produce your outcomes. The blood test is instead used in conjunction with ultrasonography called a nuchal translucency (NT) scan, which analyzes the clear tissue at the back of your baby’s neck.
Why the Double Marker Test is Done?
The first-trimester screening (dual marker test and NT scan) is optional. However, the screening (as well as others such as the cell-free DNA test) is suggested if you are over the age of 35 or have a high risk of chromosomal issues, like if you have a family history of some diseases.
It’s important to keep in mind that the result only informs you whether you’re at a higher risk of having trisomies. It does not conclusively determine whether or not your baby is abnormal.
Before making a decision whether or not to have a double marker test, consider what the results would say to you in the long run.
Would identify about possible abnormalities make you feel better or worse?
Would you want to undergo more invasive testing if the results indicated a higher risk?
Would the findings affect how you manage your pregnancy?
It all comes down to personal preference and your medical history, so there are no right or wrong answers to your queries.
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Timing Require for the Double Marker Test
The double marker test has a relatively narrow time window in which it can be conducted. Your doctor will schedule an appointment for you near the end of your first trimester or possibly very early in the second trimester.
More particularly, your blood will be drawn between weeks 11 and 14.
Cost of the Double Marker Test
Cost in India
The cost of the Double Marker Test varies depending on a variety of factors such as city, quality, and availability of the test, as this test is only available in a few cities. The average Double Marker Test Cost is usually on the higher side and quite costly. In Bangalore, the cost of a double marker test ranges between 2500 and 3500 rupees. However, these prices are only indicative, and actual prices may differ.
Cost in USA and Canada
The cost of the double marker test is determined by your insurance coverage and location. While the test is voluntary, it may be covered by your health insurance policy.
Call your insurance company to find out if you have coverage and if you need pre-authorization. If you don’t have insurance, you can call your hospital or lab to find out how much it will cost and whether there are any payment plans or rebates available.
This test is usually performed in conjunction with the NT scan, so you’ll need to pay for both to get the full first-trimester screening.
Double Marker Test Procedure
The double marker test is a straightforward blood test. Your doctor will issue you an order to take to a lab. Because it is a non-fasting test, you may eat or drink generally before your appointment except as otherwise advised.
When it comes to turnaround time, labs vary. In particular, you can expect to receive your results in 3 to 7 days. You should inquire whether your clinic will contact you or if you should contact to obtain your results.
You should inquire whether your clinic will contact you or if you should contact to obtain your results.
A Double Marker Test is performed with an ultrasound test and a blood sample. The Double Marker Test searches for two markers: Free Beta hCG (human chorionic gonadotrophin) and PAPP – A. (Pregnancy-associated plasma protein A).
Throughout pregnancy, the placenta produces a glycoprotein hormone called free beta hCG. Its high level indicates an increased risk of Trisomy 18 and Down syndrome.
PAPP – A is a necessary plasma protein. A low plasma protein level indicates the possibility of Down syndrome.
The test results are classified as screen positive, high risk, or screen negative.
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Normal Result of the Double Marker Test
The normal value of hCG in pregnant women is 25700-288000 mIU/ml for all age categories, while the normal value of PAPP – A for the female gender across all age categories is 1 MoM (multiples of median).
You will be assigned a risk level of low, moderate, or high.
Low-risk (“screen-negative”) is considered a “normal” result and indicates that your baby is unlikely to have chromosomal abnormalities.
If your result is within the normal range, you will only be recommended for further testing if there is another indicator (such as family history, age, etc.) or if you want to learn more for another reason.
However, a low-risk result does not always imply that your baby will be fine. It’s also worth noting that the first-trimester screening only looks for Down syndrome, trisomy 13, and trisomy 18 markers, not other conditions.
Abnormal Result of the Double Marker Test
If your screening results show that you are at moderate- or high risk for abnormalities (“screen-positive”), you may want to discuss your results with a genetic counselor to learn more.
More definitive, and sometimes more invasive, tests, such as noninvasive prenatal testing (NIPT), amniocentesis, or chorionic villous sampling, can be used to confirm your results. Though some of these tests may endanger your pregnancy, they do provide a conclusive result.
Because the double marker test is performed early in your pregnancy, the results provide you with enough time to make important decisions about additional testing, medical treatments, and the overall management of your pregnancy and delivery.
Identifying your risk can also help you to prepare for the possibility of having a child with special needs and find the support you’ll require.
The Double Marker Test vs NT Scan
In the first trimester, the double marker test (blood test) and NT scan (ultrasound) can be used together for the most detailed predictions. The information collected from both tests is what determines whether there is a low-, moderate-, or high risk of abnormalities.
The NT scan is just less effective for detecting potential abnormalities when conducted without the double marker test.
The NT scan allows your healthcare provider to obtain a real-time image of your baby by using sound waves. It is done at the same time as your double marker test.
Your health professional can measure the size of the clear area on the back of your baby’s neck at that point in pregnancy — late in the first trimester. Your doctor will also look at the growth of the nasal bone, which could be another sign of a trisomy.
These readings are combined with the results of your blood tests and your age-related risk. They are all added together to determine your baby’s risk of Down syndrome, trisomy 13, or trisomy 18.
Research and Studies about the Double Marker Test
According to studies, nearly one in every twenty pregnancies may have birth defects ranging in severity from anatomical abnormalities to mental retardation. Based on certain factors, some couples are far more likely than others to have a child with birth defects. This risk for an inherited condition can be determined through genetic testing. This screening, which is typically performed after eight weeks of pregnancy, employs a variety of diagnostic tests to assist in identifying couples who are at an increased risk of age-related or familial genetic disorders, as well as birth defects caused by toxic or environmental exposures. Prenatal screening tests are frequently non-invasive and can be completed in minutes.
A double marker test, also known as a dual marker test, is a type of prenatal blood test performed during the first trimester of pregnancy to look for any abnormalities in the baby’s chromosomal development. Such chromosomal anomalies can result in severe health conditions and disorders that can affect the baby’s development within the womb or later in life. The double marker test can help identify the possibility of certain disorders such as Down’s syndrome or Edward’s syndrome in advance. This test is frequently recommended because it is a very reliable test that detects abnormalities quite accurately.
Doctors consider the following factors before prescribing the double marker test: if the woman is over 35 years old, if there is a family history of congenital disabilities, and if there is a family history of diabetes. A double marker test is essentially a blood test that requires no preparation. Prior to taking the test, any medical conditions or allergies must be disclosed to the doctor. You may be asked to stop taking certain medications before the blood test.
The ultrasound is used to perform the double marker test, and the results are usually divided into two categories: screen positive and screen negative. The results of the test are determined not only by the blood samples collected but also by the mother’s age and the age of the foetus as determined by the ultrasound. All of these factors interact to determine the outcome. The levels of the hormone free-beta HCG and pregnancy-associated plasma protein A are measured in the blood sample (PAPP-A). The placenta produces this glycoprotein hormone during pregnancy. High levels of free-beta HCG indicate a higher risk of Down’s syndrome, and low protein levels also indicate a risk of Down’s syndrome.
The results of the double marker test are presented as ratios. If the ratio is between 1:10 and 1:250, it is considered a “screen positive” result, indicating that the patient is in the high-risk category. A ratio of 1:1000 or higher is considered a “screen negative” result, indicating a low risk. These ratios are indicators of a child’s proclivity to suffer from any disorder. If the double marker test results are positive, the doctor may recommend additional diagnostic procedures such as amniocentesis or chorionic villus sampling to determine the source of the problem.
Preparation for the Double Marker Test
The Double Marker Test is a straightforward blood test that requires no preparation. The doctor, on the other hand, must be concerned about the medicines being taken before the test.
Double Marker Test Summary
Is it better to test or not to test? If you’re unsure what to do, start by weighing the benefits and drawbacks of the double marker test and first-trimester screening. Consider how knowing this information might influence your decision to undergo additional testing, as well as how you manage your pregnancy.
Speak with your healthcare provider about this test and its utility in light of your specific circumstances. Whatever you decide, maintaining close contact with your healthcare provider is critical to a healthy pregnancy.
Last Updated on February 23, 2022 by Learn From Doctor Team