Double Marker Test – Benefits, Procedure and Results

A woman has to undergo a lot of tests during pregnancy. Some tests are conducted to ensure the good health of both the mother-to-be and the baby. Doctors usually recommend additional tests if they suspect any issues. The double marker test in pregnancy is one such test, performed to assess the risk of certain chromosomal abnormalities in the baby, such as Down syndrome. It is often conducted in combination with an ultrasound and is also referred to as the dual marker test in pregnancy. This test provides crucial insights and helps ensure timely medical intervention if needed.

What Is a Double Marker Test?

Looking for the double marker test meaning? A double marker test is a specific type of blood test that is conducted to detect any chromosomal abnormalities in the baby. Having any abnormalities in the chromosomes can lead to severe health conditions and disorders that can affect the baby’s growth within the foetus, or even later in life. With the help of this test, one can know beforehand about the presence or possibilities of certain disorders like Down’s syndrome, Edward’s syndrome, etc.

Also Read: Genetic Testing during Pregnancy

Why It Is Required

The double marker test is usually performed in the first trimester of pregnancy, i.e., between 8 and 14 weeks of pregnancy. It is generally recommended for women who are above 35 years of age because they are at a higher risk of giving birth to babies with defects. However, younger women are also asked nowadays to undergo this test, especially the ones who have a history of congenital disabilities in their family.

What Are the Advantages of Double Marker Tests?

The double marker blood test in pregnancy helps detect chromosomal abnormalities in the foetus. But this is just one of the reasons for conducting this test. Some other reasons why doctors suggest this test are mentioned below:

The double marker test is a very reliable test, and most of the time, it helps detect any abnormalities or issues accurately.

In case the test results are positive, i.e., the chromosomal abnormalities are detected, further diagnostic procedures or measures can be undertaken to pinpoint the problem. This test helps identify the anomalies soon.

Doctors usually recommend an advanced test to check for Down’s syndrome or Edward’s syndrome in the baby once this test is conducted. Performing this test, helps a doctor identify a problem and provide the necessary course of treatment before it becomes too late.

In case the test results are positive, and a neurological condition is diagnosed,  you can choose to terminate the pregnancy without complications, in the early stages of pregnancy.

Also Read: Blood Tests in Pregnancy

Are There Any Disadvantages of Double Marker Tests?

The disadvantages of this test are not known. Since doctors recommend this test only when they deem it essential, it may not be available in all the cities. If your doctor advises this test, you might have to travel to another city for the same.

How to Prepare for the Test

As double marker test is essentially a blood test, no specific preparations will be required from your end. However, if you are on any medications during pregnancy, inform your doctor about it. In rare cases, you might be advised to stop taking the medication until the test is undertaken. Also, if you have any allergies or medical conditions, do let your doctor know about it.

How Is This Test Performed?

The double marker test is a blood test which is performed with an ultrasound. Once the blood samples are acquired, they are observed to check the levels of the hormone free-beta hCG and pregnancy-associated plasma protein A  (PAPP-A). This glycoprotein hormone is developed during the pregnancy by the placenta. The high levels of the free-beta hCG indicate a higher risk of Down’s syndrome. On the other hand, low levels of protein pose a risk of Down’s syndrome.

Also Read: Urine and Urine Culture Tests in Pregnancy

How Are the Test Results Interpreted?

The double marker test results usually fall into two categories: screen positive and screen negative. The results of the test do not merely depend on the blood samples but also on the age of the mother and the age of the foetus, as observed during the ultrasound. All these factors work together in determining the result. The results are presented in the form of ratios. A ratio of 1:10 to 1:250 is termed a “screen positive” result, which lies in the high-risk zone. A ratio of 1:1000 or above is termed a “screen negative” result, which poses a low risk.

These ratios are pointers for understanding the probability of the baby suffering from a disorder. Each ratio depicts the chances of the child having a disorder over a number of pregnancies. A 1:10 ratio means that 1 child out of 10 pregnancies has a chance of developing a disorder, which is quite high. A 1:1000 ratio means 1 child out of 1000 pregnancies will have the disorder, which is negligible.

In case the test result is positive, your doctor, based on the ratios, might recommend you further diagnostics, mainly amniocentesis or chorionic villus sampling.

What Are the Normal Values of the Test?

The normal range of the double marker test is depicted as follows.

What Is the Difference Between a Double Marker and an NT Scan?

The NT scan is an ultrasound procedure, whereas the double marker test involves a blood sample. Beyond their testing methods, there are no major distinctions between the two. Both are typically advised during the first trimester, and doctors often recommend conducting both tests as part of the first-trimester screening to obtain the most reliable results. In fact, the NT scan is deemed less effective if it is not accompanied by the double marker scan.

What Is the Cost of the Test?

The cost of double marker test will vary across cities and hospitals. The double marker test price would be somewhere between Rs. 1000 and Rs. 5000. The average cost of this test is about Rs. 2500 in many cities.

FAQs

1. Can my previous pregnancies affect the Double Marker Test results?

Yes, if you have had previous pregnancies with complications or specific genetic conditions, it may influence the interpretation of your Double Marker Test results. Your healthcare provider may consider your obstetric history when assessing your risk levels and may recommend additional screenings.

2. Can the results of the Double Marker Test change as the pregnancy progresses?

Yes, the risk assessment from the Double Marker Test can change based on additional factors that arise during the pregnancy. For instance, if you receive a high-risk result, follow-up testing and monitoring may provide updated information, potentially leading to different conclusions as more data becomes available.

3. Are there specific populations that should consider the Double Marker Test more seriously?

Certain populations, such as women over the age of 35, those with a family history of genetic disorders, or individuals from ethnic backgrounds with higher prevalence rates for specific conditions, may be advised to take the Double Marker Test more seriously. These groups may have a higher risk of chromosomal abnormalities, making early screening particularly important.

While pregnant, you pray for nothing more but good health of your child. To ensure that your baby is healthy and grows up to lead a normal life, you must follow a balanced diet, incorporate necessary lifestyle changes, and make the right efforts to keep yourself and the baby safe. However, there are chances that even after doing the right thing, the test results could point towards the presence of a disorder in the baby. In such a case, you should discuss with your spouse whether you want to keep the baby or not. The decision to terminate the pregnancy would obviously be hard to make, but you should consider the consequences. If you can’t come to a conclusion, consult with your doctor, he will suggest what you should do.

References/Resources:

1. Liteanu. A, Mihhùan. M, Artenie. V; The importance of the double test in identification of high risk pregnancies for chromosomal diseases development; ResearchGate; https://www.researchgate.net/publication/265533702_The_importance_of_the_double_test_in_identification_of_high_risk_pregnancies_for_chromosomal_diseases_development; February 2010

2. Dayem. T, El-agwany. A, Soliman. T, Kholief. A; Double marker test and uterine Doppler in cases with hyperemesis gravidarum (Evidence Based Womenʼs Health Journal); ResearchGate; https://www.researchgate.net/publication/281352102_Double_marker_test_and_uterine_Doppler_in_cases_with_hyperemesis_gravidarum; August 2015

3. Down Syndrome; CDC Birth Defects; https://www.cdc.gov/birth-defects/about/down-syndrome.html

4. Screening tests for Down’s syndrome in first three months of pregnancy; Cochrane; https://www.cochrane.org/CD011975/PREG_screening-tests-downs-syndrome-first-three-months-pregnancy

5. Down syndrome; Mayo Clinic; https://www.mayoclinic.org/diseases-conditions/down-syndrome/diagnosis-treatment/drc-20355983

6. Prenatal testing: Is it right for me?; Mayo Clinic; https://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/in-depth/prenatal-testing/art-20045177

7. Shiefa. S, Amargandhi. M, Bhupendra. J, Moulali. S, Kristine. T; First Trimester Maternal Serum Screening Using Biochemical Markers PAPP-A and Free β-hCG for Down Syndrome, Patau Syndrome and Edward Syndrome (Indian Journal of Clinical Biochemistry); National Library of Medicine; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3547446/; October 2012

Also Read:

Triple Marker Test during Pregnancy
Quadruple Marker Test in Pregnancy
Sequential Test while Pregnant
Common Trimester Wise Test in Pregnancy
Screening and Diagnostic Tests in Pregnancy for Birth Defects

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