Double marker test is also known as dual marker test/maternal marker test. This test is done of a pregnant woman to detect any genetic abnormalities in the fetus. The risk of genetic abnormalities like Down’s syndrome, Edward syndrome is more in pregnant women of age above 35 years and has a family history or history of genetic abnormalities in a previous pregnancy.
Double marker test is also very useful to detect any neurological condition of the fetus.
What is Double Marker Test?
Double marker test of a pregnant woman is very essential to detect any genetic/chromosomal abnormalities of the fetus. The term “Double” two specific hormones and the test is performed to measure the two hormones ………
- Beta human chorionic gonadotropin ( β-HCG ): This hormone produced in a greater amount by the placenta during pregnancy. β-HCG level increases in the first 8-10 weeks of pregnancy and then decreases to stable value which remains stable for the rest of the pregnancy.
- Pregnancy-associated plasma protein in the blood ( PAPP-A ): This protein produced by the growing placenta and its levels in the blood increase during pregnancy until the time of delivery.
- If the test result is positive, the parent may consult with the doctor for termination of pregnancy as per MTP rules.
- If tested negative that means the risk of genetic abnormalities of your baby is less.
What is the normal range of β-HCG?
The normal value of β-HCG 25700-28800 mlu/ml.
What is the normal range of PAPP-A?
It should be greater than 0.5 mom.
What is the right time for double marker test?
The patient’s blood sample is collected for the test. The right time to go for the test is 10-13 weeks of pregnancy. But as per doctor’s advice, the test can be done between 9-13.6 weeks of the pregnancy.
Why is the double marker test so important?
The dual marker test is very important for screening the fetus. The test result informs about any genetic abnormalities like down’s syndrome, which may affect the future baby. So, with this test, such types of genetic abnormalities may be prevented.
The image describes the incidence of down’s syndrome with the age of a pregnancy
As we can see from the graph, the risk is all most constant up to the age of 30 and after that, the risk increases rapidly with maternal age.
It is considered that the pregnant women of age above 35 years must go for the test as they have high risk.
The women are also at risk who have a family history or previous history of pregnancy with genetic abnormalities.
The younger pregnant women are also advised to do the test because any pregnancy always has a finite risk of genetic abnormalities. So, it is better to do the test.
To confirm any suspected genetic abnormalities, it is very important to do the dual marker test with Nuchal Translucency (NT) test.
What is Nuchal Translucency (NT) Test?
NT is normal ultrasonography. The test measures nasal bone, fluid at the back of the baby’s neck.
The high amount(volume) of fluid may be the sign of problems. This is not a diagnostic test, only predict about the risk.
If the test result is positive then your doctor may advise for further tests like CVS.
The test takes about 20-40 minutes & it is safe for both mother and baby.
What is Down Syndrome?
It is named after the British physician John Langdon Down.
Down syndrome is a genetic disorder caused by an error in cell division resulting in the presence of the third chromosome 21 or trisomy 21.
The babies with down syndrome will have………
- Delayed cognitive ability ( mental retardation)
- Intellectual disability ( long term memory, short term memory both effected, language is delayed )
- A particular set of facial characteristics ( flattened face, small head, short neck )
What is Edward syndrome?
Edward syndrome, also known as Trisomy 18, is a genetic condition.
Trisomy 18 is the cause of having three copies of chromosome 18 instead of two copies.
This affects the normal growth and development of the baby.
The baby may have a serious condition of heart, respiratory system, kidney, etc.
FAQs about the test
What is the purpose of dual marker test?
The test actually helps to find out any genetic abnormalities of the fetus.
What is the process of the test?
Collected blood samples from vain go for tests in the lab.
What is the right time to do the test?
The ideal time to do the test is 10-13 weeks of pregnancy.
Who is at more risk?
The pregnant women of age above 35 years are at more risk to delivering a baby with genetic abnormalities. The women also at risk who have a family history or previous history of pregnancy with genetic abnormalities.
Can pregnant women of any age do the test?
Yes, because every pregnant woman of age below 35 has some risk.
What are the two specific hormones in the dual marker test?
The dual marker test is performed to measure the two hormones ………
- Beta human chorionic gonadotropin ( β-HCG )
- Pregnancy-associated plasma protein in the blood ( PAPP-A )
What is the normal range of β-HCG and PAPP-A?
The normal value of β-HCG 25700-28800 mlu/ml.
PAPP-A should be greater than 0.5 mom
What are the side effects of the test?
The test has no side effects.
What to do if tested positive?
If the test result is positive, the parent may consult with the doctor for termination of pregnancy as per MTP rules.
What to do if tested negative?
If tested negative that means the risk of genetic abnormalities of your baby is less.
What is the cost?
The cost of the test varies and it ranges from Rs- 1000/- to 5000/-.
Why does the doctor advise for Nuchal Translucency (NT) Test?
For confirmation of any suspected genetic abnormalities, it is very important to do the dual marker test with Nuchal Translucency (NT) test.
What are the side effects of Nuchal Translucency (NT) Test?
NT is simple ultrasonography and it has no side effects for both baby & mother.
How does double marker test help?
- helps in detecting any genetic abnormalities of the fetus.
- detection of down syndrome.
- helps to detect Trisomy 18.
- helps to assess any mental disorder of unborn babies.