Home›Double Marker Test- First Trimester

Content created by

Written by

Dr. Shreya Gupta

BDS, MDS - Oral and Maxillofacial Pathology

Reviewed by

Dr. Ashish Ranjan

MBBS, MD (Pharmacology)

Want to know more?
Read our Editorial Policy

Double Marker Test- First Trimester

Also known as Dual Marker Test, Maternal Serum Screening (MSS) - First Trimester

₹2160~~₹2400~~ 10% Off

You need to provide

Blood

This test is for

Female

Earliest reports in

48 hours

Test Preparation

A duly filled Maternal Serum Screen requisition form is mandatory.
Provide information like maternal date of birth (dd/mm/yy), last date of the menstrual cycle (LMP), number of fetuses (single/twins), diabetic status, body weight in kg, and history of IVF, smoking, and Trisomy 21 pregnancy.
Keep a hard copy of the latest pregnancy ultrasound report (Date of scan, CRL, NT in mm/NB, Level 1) - this is mandatory for combined risk assessment.
The test is valid between 9 to 13 weeks of gestation (the ideal time for combined risk assessment is between 11 to 13 weeks).

Understanding Double Marker Test- First Trimester

What is Double Marker Test- First Trimester?

The Double Marker Test- First Trimester also known as a dual marker test, assesses specific biomarkers in a pregnant woman’s blood. It is done during the first trimester of pregnancy, usually between 11-13 weeks. This test provides information about the risk of certain birth defects such as Down syndrome (Trisomy 21), Edward syndrome (Trisomy 18), and Patau syndrome (Trisomy 13) in the developing fetus.

Prenatal care is necessary to ensure a healthy pregnancy and successful childbirth. Early prenatal screenings identify potential health concerns and guide medical interventions when necessary. The Double Marker Test- First Trimester is essential for early prenatal assessment. It offers invaluable insights into the developing fetus's chromosomal health. The test primarily measures two important biomarkers in the mother’s blood—human chorionic gonadotropin (hCG) and pregnancy-associated plasma protein A (PAPP-A). Both the markers are produced by the fetus and the placenta.

The test also checks if the baby might be at risk for certain genetic problems, especially Down syndrome and Edwards syndrome. These conditions happen when there is an extra copy of chromosome 21 or 18, respectively. They can affect a baby's physical and intellectual development. However, a Double Marker Test-First Trimester is a screening test, not a diagnostic one. It does not determine whether your baby has abnormalities. Instead, it tells whether the unborn baby is at risk of developing certain abnormalities.

The test results are reported as a risk score or probability of the fetus having a chromosomal abnormality. Test results within the expected range suggest a lower risk of chromosomal abnormalities. On the contrary, high levels may indicate a higher risk of chromosomal abnormalities and prompt further testing. Furthermore, a positive screen result (high risk) does not confirm a genetic problem. It may suggest that further testing may be needed to check the baby's health more closely. On the other hand, a negative screen result (low risk) does not guarantee the absence of fetal defects.

In combined risk assessment, the NT scan (a type of ultrasound) is also used to check for conditions like Down syndrome and Patau syndrome. This, along with the mother’s details—such as age, weight, smoking, diabetes, or IVF pregnancy—is included in the overall risk calculation. However, this test does not check for neural tube defects.

No fasting is required for a Double Marker Test-First Trimester. Let your doctor know about any medical conditions, allergies, or medicines you are taking, as some medicines may affect the test results and might need to be stopped before getting tested.

Talk to your doctor about your specific test results. The accuracy of the results is subjective to the information provided in the screening form. This information is mandatory for combined risk assessment.

What is Double Marker Test- First Trimester used for?

The Double Marker Test- First Trimester is done:

For the early risk assessment of Down, Patau and Edward syndromes in developing fetuses.
In pregnant women above 35 years of age and those with a family history of birth defects and a history of insulin-dependent type 1 diabetes.

What does Double Marker Test- First Trimester measure?

The Double Marker Test- First Trimester measures two biomarkers in maternal blood associated with chromosomal abnormalities.

a) Free beta-hCG (human chorionic gonadotropin): a hormone made by the placenta shortly after a woman becomes pregnant.

b) PAPP-A (pregnancy-associated plasma protein-A): a protein made by the placenta during early pregnancy. It helps the placenta grow and function properly.

These, along with the USG marker and nuchal translucency (NT) measurement, are effective in Combined screening for Down syndrome and trisomy 13/18 in the fetus. This test only gives the risk for the presence of these chromosomal abnormalities in the developing fetus. A positive screen is not diagnostic but indicates that further evaluation should be considered.

hCG is synthesized by the placenta very early in pregnancy and can be detected in the blood 8-11 days after conception. Higher levels of hCG after 11 weeks of gestation may suggest a higher chance of the baby having Down syndrome. On the other hand, low levels indicate an increased risk for trisomy 18.

PAPP-A is a protein produced by the placenta that is needed for the implantation and maintenance of a healthy placenta (afterbirth). Low levels of PAPP-A before the 14th week of pregnancy suggest an increased risk of fetal chromosomal abnormalities.

Interpreting Double Marker Test- First Trimester results

Interpretations

All women should be screened with a dual marker test during pregnancy for any pre-birth abnormalities, irrespective of age. The ideal duration of this test is between the 10th and 13th weeks of pregnancy. But it can be done between the 9th and 13th weeks of pregnancy.

Frequently Asked Questions about Double Marker Test- First Trimester

Q. What is the Double Marker Test- First Trimester and why is it performed?

The Double Marker Test- First Trimester is a prenatal screening test for pregnant women. It helps assess the risk of chromosomal abnormalities in the developing fetus. It is performed to assess the risk of potential genetic conditions such as Down syndrome and Edwards syndrome.

Q. What is the difference between a Double Marker Test- First Trimester and an NT scan?

An NT scan is an ultrasound, and a dual marker is a blood test. Both of the tests are done during the first trimester to screen for the possible risk of chromosomal abnormalities in the unborn child.

Q. How early can a dual marker test be conducted during pregnancy?

A dual marker test is typically conducted during the first trimester of pregnancy, i.e., between weeks 9 and 13. But it is advised to get tested between 11 - 13 weeks along with NT values from the USG report as it gives Combined risk assessment which is better.

Q. Is there any risk associated with the Double Marker Test- First Trimester?

No, the Double Marker Test- First Trimester is generally safe with minimal risks. However, you may feel slight discomfort during blood sample collection, but the chances of serious complications are extremely rare.

Q. Do I need to fast before taking the Double Marker Test- First Trimester?

No fasting is required for this test. You can schedule it at your convenience without avoiding food or water beforehand.

Q. What is a Combined Risk Assessment?

The first-trimester screening combines two blood tests and a special ultrasound (with NT measurement in mm, CRL value, and nasal bone (NB). In combined risk assessment, the risk score from blood tests is interpreted in conjunction with the nuchal translucency (NT) measurement and maternal demographic information like age, weight, smoking, diabetic status, IVF pregnancy, etc., to assess the overall risk profile. This increases both the sensitivity and specificity of the screening results.

Q. What does a negative screen mean?

A negative screen means it is unlikely the fetus has Down syndrome, trisomy 18. However, a negative screen does not guarantee the birth of a healthy baby. The screening test only screens for Down syndrome and trisomy 18; it is not a diagnostic test. The maternal demographic information also is used to help calculate the baby’s risk of having Down syndrome or Trisomy 18. Please check the demographic information to ensure the accuracy of the calculated results.

Q. What chromosomal abnormalities are screened by the Double Marker Test- First Trimester?

The dual marker test screens for: a) Down syndrome (Trisomy 21); b) Patau syndrome (Trisomy 13); c) Edwards syndrome (Trisomy 18).

Q. How is the Double Marker Test- First Trimester performed, and is it safe for the baby?

The test involves a simple blood draw from the pregnant woman and poses no risk to the developing fetus. Furthermore, the test is noninvasive and carries no risks to the pregnancy. It is considered a safe screening test.

Q. Can the Double Marker Test- First Trimester identify the specific chromosomal abnormalities in the fetus?

The dual marker is a screening test and not a diagnostic test. It screens for the risk of chromosomal abnormalities and doesn’t identify the specific abnormality. Confirmatory tests are required for a definitive diagnosis.

Q. What is Down syndrome?

Down syndrome, also known as Trisomy 21, is a genetic disorder caused by the presence of an extra copy of chromosome 21 in a person's DNA (genetic material). It can cause various physical and intellectual challenges.

Q. What is Edwards’ syndrome?

Edwards’ syndrome, also known as Trisomy 18, is a rare genetic disorder caused by the presence of an extra copy of chromosome 18. It typically results in severe intellectual and developmental disabilities.

Q. What if a dual marker test is missed?

If you miss the time for the Dual Marker Test, your doctor might suggest another test, like the Quad Marker Test. Quad Marker test is usually done between the 15th and 21st week of pregnancy.

Q. Is it a mandatory test?

No, it is an optional test. However, doctors often recommend it for early screening, especially for women over 35 or with a family history of genetic conditions.

+ more