Is your NT Scan Normal but Blood Test Abnormal?

The NT scan is one of the most important screening processes during the first trimester, as it detects if the baby has any chromosomal abnormalities.

Along with the NT scan, you will also be recommended a blood test called a dual marker or double marker test. Both of these tests together can increase the accuracy of the results.

Sometimes, the results can come out as NT scan normal but blood test abnormal. Why is this so? Let’s discuss this briefly.

What is NT Scan?

The NT scan measures the amount of fluid present in the back of the baby’s neck.

It is an ultrasound scan that can detect if the baby has any chance of having congenital disorders like Down syndrome, heart defects, etc.

During the first trimester of pregnancy, doctors suggest you take an NT test. NT stands for Nuchal translucency.

What is the Double marker test?

A double marker test means a blood test that detects the two markers HCG and PAPP-A (pregnancy-associated plasma protein) in the blood along with an ultrasound.

The double marker, also called a dual marker test, is used to evaluate the risk of a baby having any chromosomal abnormalities.

When should an NT scan be done with a blood test?

The doctor suggests you take an NT scan during the first trimester. It is recommended to take both an NT scan and a double marker test on the same day for accurate results.

Which is more accurate: NT scan or double marker?

The NT scan report contains

• A few basic details of the mother, her age, etc.
• The baby’s measurements (CRL, BPD, HC, etc.), are usually measured in mm.
• Nuchal Translucency fluid measurement.

If the NT measurement is below 3mm, then it is less likely for the baby to have any chromosomal abnormalities.

The blood marker tests for HCG and PAPP-A and the result comes as low risk, moderate risk, or high risk of the baby being born with any abnormalities.

The NT test can provide only 70% accuracy in determining whether or not the baby has any chromosomal abnormalities, but when combined with a double marker test, the accuracy is around 80%.

So it is a better idea to perform both tests together instead of choosing one.

Can I get normal NT value but abnormal blood test result?

Yes, it is possible for some pregnant women to get normal NT scan results and abnormal blood test reports.

What to do if the NT scan is normal but a blood test is abnormal?

Yes, it is possible for your report to turn out this way. Sometimes, your NT Scan can be normal and your blood tests can be abnormal.

But having a positive dual marker test doesn’t 100% mean that the baby has an abnormality.

The doctor suggests a few more tests, like NIPT, CVS, or amniocentesis, to determine the chances of the baby having chromosomal abnormalities.

For some patients, a second-trimester screening is done to check whether the baby is normal, along with a blood test.

So it is recommended that you talk to your fetal medicine specialist with your reports for guidance and more information on this.

Conclusion

There are possibilities for your reports to come out as NT scan normal but blood test abnormal.

This doesn’t mean 100% confirmation that the baby has chromosomal abnormalities, as the NT scan can detect about 70% accurate results.

If your results are a normal NT scan and abnormal blood tests, doctors carry out a few other tests like NIPT, CVS or amniocentesis to rule out the chances of the baby having abnormalities.

Please talk to your fetal medical consultant. Book an appointment with Jammi Scans for accurate NT and other pregnancy scan reports.