Double Marker vs Triple Marker : Which is the better test in pregnancy?

Double Marker or Dual Marker and Triple Marker are blood tests done in pregnancy to detect genetic problems in the baby. Both tests provide a risk assessment, but which test is better? We explore the two tests, their differences and which test you should do!

Published Date : 2024-08-27T09:46:44.476Z

Updated Date : 2024-08-27T10:08:16.229Z

Double Marker and Triple Marker Tests - What are they?

The double marker and triple marker tests are blood tests done on the mother during pregnancy. They measure different hormones and proteins in the mother's blood to determine the chances of the baby having a genetic abnormality, such as Down's Syndrome. The tests are simple blood tests.

Double Marker Test

In this test, two substances are measured in the the mother's blood - Free Beta Hcg and PPAP-A. Based on their levels a statistical calculation is done to determine the chances of the baby having Down's Syndrome. This test is done between the 11th to 14th week of pregnancy.

Triple Marker Test

The triple marker test is a blood test that is done on the mother during pregnancy, in the second trimester (usually between weeks 15-20). The test measures three hormones - beta hcg, alpha feto protein and Free Estrioi. Based on their levels a risk assessment is done for Down's Syndrome.

Which test is better to detect Down's Syndrome?

Both tests screen for Down's syndrome. The double marker test, is surprisingly more accurate in predicting Down's Syndrome. It has an accuracy rate of 82% to 87% in predicting Down's Syndrome. The triple marker on the other hand, has an accuracy of only 69% in predicting Down' Syndrome.

Does a positive Double Marker Test mean that the baby definitely has Down's Syndrome?

No. A positive screen only means that there is a higher risk of the child developing Down's Syndrome, and more testing will have to be done to confirm the diagnosis. Neither the double nor the triple marker tests are confirmatory.

What is the advantage of the Triple Marker Test over the Double Marker Test?

The triple marker test, while it has a lower accuracy at Down's Syndrome prediction, can also predict the chances of Neural Tube Defects.

What are neural tube defects?

Neural tube defects are abnormalities in the brain or spinal chord of the child, that causes the spinal chord to sometimes protrude from the back. These are usually caused due to inadequate vitamins in the mother's diet. The triple marker test can detect the risk of these, but the double marker test does not

Which test should you do? Which is better?

Both the tests have their own value. Firstly, the double marker test can be done earliest in pregnancy and so it is always recommended to get this done as a part of first timester screening tests in pregnancy. If you missed taking the double marker test, you should definitely get the triple marker test done in the second trimester. Neither of these tests is optional, since they screen for different disorders and have different time frames. We recommend that the double marker and the triple marker should both be done at the recommended times of pregnancy.

What about the quadruple marker test?

The quadruple marker test is an alternative to the triple marker test, and offers slightly better detection for Down's Syndrome. Some doctors recommend getting the quadruple marker test, in place of the triple marker test. In our view, the quadruple marker test is more expensive and offers little advantage over the triple marker test.