The double marker test in pregnancy, also known as maternal serum screening, is part of another comprehensive assessment known as the first-trimester assessment. It is not definitive proof. Instead, it is classified as a predictive test, meaning its results inform the likelihood of chromosomal abnormalities. This test detects blood levels of free human beta-chorionic gonadotropin (beta-hCG) and pregnancy-associated plasma protein A (PAPP-A).
In a typical pregnancy, there are 22 pairs of XX chromosomes in female fetuses or 22 pairs of XY chromosomes in male fetuses. A chromosomal disorder known as a trisomy is one in which there are additional chromosomes, such as:
· Down syndrome: This common trisomy is also known as trisomy 21 because there is an extra copy of chromosome 21.
· Trisomy 18 and trisomy 13: These shared chromosomesAnomalies involve an extra copy of chromosome 18 (Edward syndrome) or chromosome 13 (Patau syndrome).
Level SHCG and PAPP-A may be higher or lower than “normal” in pregnancies with these chromosomal abnormalities. However, blood levels alone do not drive the results. Instead, the blood test is used in conjunction with an ultrasound, called a nuchal translucency (NT) scan, which examines the clear tissue in your baby’s neck.
Why is a double marker test performed?
First-trimester screening, double marker test, and NT scan are not required. That said, screening (and others like cell-free DNA testing) is recommended if you’re over the age of 35 or at an increased risk of chromosomal problems.
If you have a family history of certain medical conditions, before you decide to take a dual marker test, ask yourself what the results would mean for you in the long term. Would knowing about possible abnormalities reduce or worsen your anxiety? If you get a result like that, you may want to undergo more invasive testing. Does it indicate an increased risk? Would the results change the way you would manage your pregnancy? This is a personal decision and your health history, so there is no right or wrong answer to your questions.
Time of the double marker test
There is a relatively small time window in which the double marker test can be carried out. Your doctor will ask you to make an appointment towards the end of the year, our first trimester, or possibly very early in your second trimester.
More specifically, your blood will be drawn sometime between 11 and 14 weeks.
What to expect from the tests
Dual marker test is a simple blood test. Your doctor will direct you to take it to a lab. This is a non-fasting test, you can eat or drink normally before your appointment unless otherwise directed. Laboratory values vary when it comes to response time. In general, you can expect to receive your results in approximately 3 days to a week.
Standard results for the double marker test
You will receive standard results for dual marker tests, a low, medium, or high-risk result. A low-risk (“negative screen”) result is considered a “normal” result and means a low chance that your baby has chromosomal abnormalities.
If your result is within the normal range, further testing is only recommended if there are other indicators (such as family history, age, etc.) or if you want more information for other reasons.
Abnormal dual marker test results in your screening test show an intermediate or high risk (“positive test”) for abnormalities, you can check your result with a genetic counselor to learn more.
Your result can be confirmed by more definitive and sometimes invasive tests, such as non-invasive prenatal testing (NIPT), amniocentesis, or chorionic villus sampling. While some of these tests carry some risk to your pregnancy, provide a definitive result.
Because the double marker test is performed early in your pregnancy, the information gives you time to make important decisions about further testing, medical treatment, etc., and the general management of your pregnancy and delivery.
Are there any risks associated with dual marker testing?
There are no risks associated with the dual marker test. It is a routine and non-invasive blood test. Of course, be sure to follow your doctor’s instructions and contact your doctor with any concerns you might have.
Also Read more about How Double Marker Test Helps Managing Pregnancy and get aware of it.
Takeaway
If you don’t know what to do, first weigh the pros and cons of dual marker testing in pregnancy and first-trimester screening. Ask yourself how knowing this information could help you make decisions about further testing and managing your pregnancy.