Double Marker Test- First Trimester

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

Prenatal care is necessary to ensure a healthy pregnancy and successful childbirth. Early prenatal screenings are crucial in identifying potential health concerns and guiding medical interventions when necessary. 

A Double Marker Test- First Trimester is an essential component of early prenatal assessment that offers invaluable insights into the developing fetus's chromosomal health. This test primarily focuses on two biomarkers, human chorionic gonadotropin (hCG) and pregnancy-associated plasma protein A (PAPP-A) in maternal serum, that are produced by the fetus and the placenta. In addition, the nuchal translucency (NT) measurement, a USG marker shown to be effective in screening fetuses for Down syndrome and Trisomy 18, is included in the risk calculation. The risk is calculated using mathematical software and includes maternal demographic information like age, weight, smoking, diabetic status, IVF pregnancy, etc. 

The dual marker test screens the fetus for the two most common chromosomal abnormalities: Down syndrome and Edwards’ syndrome. These conditions result from the presence of extra copies of chromosomes 21 and 18, respectively, and affect the baby's physical and intellectual development. This test does not screen for neural tube defects. However, remember that this is just a screening test and not a diagnostic test, meaning it does not determine whether your baby has abnormalities; instead, it tells whether the unborn baby is at risk of developing certain abnormalities.

This test is based entirely on a predictive and statistical approach and gives a risk assessment whether above or below the cut-off established by each lab. A screen-positive result (high risk) does not provide a diagnosis but indicates that further diagnostic testing should be considered. Also, a screen-negative result (low risk) does not guarantee the absence of fetal defects.

No fasting is required for a Double Marker Test- First Trimester test. However, inform your doctor about all your medical conditions or allergies before taking the test. Also, tell your doctor about the medications you are taking, as certain medications can affect the results of this test and might need to be discontinued.

Test results within the expected range suggest a lower risk of chromosomal abnormalities, whereas elevated levels of biomarkers may indicate a higher risk of chromosomal abnormalities and prompt further testing. Talk to your doctor about your specific test results.

The accuracy of the results is subjective to the information provided in the screening form, and this information is mandatory for combined risk assessment. The estimated risk calculations and screen results are dependent on accurate information for gestation, maternal age, and weight. Inaccurate information can lead to significant alterations in the estimated risk. For combined risk assessment (an important parameter that is calculated using test values along with NT (Nuchal translucency) value from Level 1 USG), getting tested in 11-13 weeks of pregnancy is always advisable and requires a USG report which shows the nuchal translucency (NT) measurement of the developing fetus.