A diagnostic tool performed to predict the probability of chromosomal abnormalities.
Helps analyze certain conditions like Down syndrome, Edward’s syndrome, and Patau’s syndrome.
This non-definitive test is part of a comprehensive first-trimester screening test, and the results can only predict the probability of chromosomal abnormalities.
Why is the Double Marker Test Done?
While the double marker test is not mandatory, it is highly recommended for women who are 35 years old or older and those who may be at higher risk of chromosomal issues due to family history or other conditions.
The test can provide useful information for parents and doctors to make informed decisions about further testing and medical treatments.
Timing of the Double Marker Test
The double marker test must be performed between weeks 11 and 14 of pregnancy. Most often, the test is done along with an ultrasound called a nuchal translucency (NT) scan.
What to Expect During the Test?
The double marker test is a simple blood test that can be done without fasting. The turnaround time for the results is generally three days to a week. The results will indicate whether there is a low, moderate, or high risk of chromosomal abnormalities.
Standard and Abnormal Results
A low-risk result is considered a “normal” result, indicating low probability of chromosomal abnormalities. However, it is important to note that a low-risk result does not rule out the possibility of abnormalities.
If the results come back moderate or high risk, further testing is recommended, such as noninvasive prenatal testing (NIPT), amniocentesis, or chorionic villous sampling. Parents may choose to go over the results with a genetic counselor to learn more.
Standard results
- The double marker test measures two hormones in the mother’s blood: PAPP-A (pregnancy-associated plasma protein-A) and free β-hCG (beta human chorionic gonadotropin).
- Normal results show that both hormones are within the expected range for the woman’s stage of pregnancy, indicating a lower risk of certain chromosomal abnormalities and neural tube defects.
Abnormal results
- Abnormal results may indicate a higher risk of certain chromosomal abnormalities or neural tube defects in the developing fetus.
However, it is important to note that abnormal results do not necessarily mean that the fetus has a disorder; further diagnostic testing such as amniocentesis may be needed to confirm.
Are there any risks associated with the double marker test?
The double marker test is considered a safe test for both mother and fetus, and there are no known risks associated with the test.
Double marker test vs. NT scan
Double Marker Test:
• A blood test that measures two hormones in the mother’s blood.
• Measures PAPP-A and free β-hCG levels in the maternal serum.
• Can be done between 9 and 13 weeks of pregnancy.
• Used to screen for Down syndrome and other chromosomal abnormalities.
NT scan:
• A non-invasive ultrasound that measures the fluid at the back of the fetus’s neck.
• Measures nuchal translucency, or the thickness of the fluid at the back of the fetus’s neck.
• Can be done between 11 and 14 weeks of pregnancy.
• Used to screen for Down syndrome and other chromosomal abnormalities.
The double marker test is a valuable tool that provides information to parents and doctors about possible chromosomal abnormalities.
It is important to understand that the test is a predictive test, and the results are not definitive. The results help parents and doctors make informed decisions about further testing, medical treatments, and other options.
