The first-trimester screening tests are used to recognize abnormalities in the unborn fetus at the early stages of pregnancy. One such type of screening test is the dual marker test.
Double Marker Test: Meaning
The double marker test (also known as the dual marker test or maternal serum screening) is a blood test that uses biomarkers to detect any possible chromosomal abnormalities early. It is a safe, non-invasive screening between 10 to 14 weeks of pregnancy. This is a simple screening test to detect high-risk pregnancies. It is not a diagnostic test. So, it is optional to opt for this screening.
Double Marker Test: Procedure
A dual marker test is a simple blood test. It is a non-fasting blood test wherein you can eat or drink unless instructed otherwise. There is no specific preparation before the blood test. This first-trimester screening test uses biomarkers like PAPP-A and Free Beta hCG to determine the possible risks.
Double Marker Test: Results and Its Detection Rate
The results of this test are outlined in the form of ratios. If the ratio is between 1:10 and 1:250, it is regarded as a “screen positive” result in the high zone. If your result is a high risk, the doctor may suggest further diagnostic testing. A ratio of 1:1000 is regarded as a “screen negative” result which shows a low risk. Low risk is considered a normal result which means that the probability of your baby having medical conditions is low. However, a low-risk result does not guarantee a smooth pregnancy.
The sensitivity or detection rate of the dual marker test is 50 percent. The dual markers without a Nuchal Translucency (NT) scan have a low sensitivity rate which is 50 percent. The sensitivity of a double marker test with an NT scan increases to 85 percent with a false positive rate of 5 percent. An NT scan combined with a double marker test and other ultrasound examination of the fetal nasal bone, assessment of blood flow across the tricuspid valve, fetal heart rate, and ductus venosus flow increase the sensitivity to 94 percent with a low false positive rate of 2.5 percent. A dual marker test alone has a poor detection rate for genetic disorders.
Benefits of Double Marker Test:
- Screening tests provide an increased risk of pregnancies along with an early review of your baby’s health.
- The dual marker test helps to detect possible risks for abnormalities such as Down Syndrome, Patau Syndrome, Triploidy, Turner Syndrome, Edward Syndrome, and other chromosomal abnormalities.
To whom is the dual marker test prescribed?
A double marker test is suggested if you are above 35 years of age or with Type-1 Diabetes Mellitus or other family histories of health conditions.
What is the Cost of a Double Marker Test in India?
The double marker test may cost anywhere between Rs 2500 to 3500.
If you are confused about opting for a dual marker test in pregnancy, it is best to consult a medical professional. The double marker test has its own set of pros and cons. To make the right choice, consult your healthcare professional about the utility of this test in detail.