QUADRUPLE TEST

What is the quadruple test?

It is a blood test that checks the concentration of four substances in your blood. These are-
alpha-fetoprotein(AFP)
total human chorionic gonadotrophin(hCG)
unconjugated oestriol(uE3)
inhibin A(inhibin)

When is it done?

It is done around 15 or 16 weeks of your pregnancy but can be done till 20 weeks as well.

What do different levels indicate?

In conditions like down syndrome, AFP and uE3 are low, and hCG along with inhibin are raised
AFP levels are used to determine if there is an increased risk of neural tube defects like spina bifida and anencephaly. The results are calculated using these levels and your age.

What if I get a positive screening for down syndrome?

If you get positive screening for down syndrome, that means your baby is at higher risk of having down syndrome. You will be offered a more invasive test called amniocentesis to confirm the screening results.

What if I get negative screening for down syndrome or neural tube defects?
If the screening results are negative. it means the risk of the baby having any of the conditions tested is low. A diagnostic test is not offered in such cases

Is screening sensitive enough to detect all cases of neural tube defects?

This screening test can detect 4 out of 5 open spina bifida, but 1 out of 5 cases are still missed. maximum cases of anencephaly are detected

Why are cases missed despite having screening done?

Although screening tests are highly sensitive, some cases can still be missed because they cannot completely rule out the possibility of a baby suffering from the tested conditions.

Why are diagnostic tests done if screening comes out to be positive?
Diagnostic tests are done to confirm the results of the screening test. It actually tells you whether the pregnancy is affected or not. A diagnostic test is in the form of amniocentesis. Amniocentesis is a procedure that involves passing a needle under ultrasound guidance through your tummy. This needle will help take out a small amount of amniotic fluid(fluid around the baby). This fluid contains cells, and they will be tested in the laboratory. The results will show if the baby is actually suffering from any of the conditions tested or not. the plan will be made according to do the results

The detection rate of quadruple test-
The quadruple test can detect 80% of cases affected with down syndrome with positive screening results. 20% of women whose baby’s are affected with down syndrome will receive normal*negative results)

Detection rate for open spina bifida
A quadruple test can detect 85% of cases of open spina bifida
detection rate for anencephaly
nearly all the cases of anencephaly are detected

What if my baby is affected with conditions tested
You will meet a fetal medicine specialist and pediatrician. They will tell you about the implications of these conditions on the baby. You can have a detailed discussion with them. You will get all the support needed. You will have two options
1 termination of pregnancy
2 continue pregnancy
It is your wish and choice of how you want to go further in your pregnancy. It is indeed, tough decision to take. It would help if you talked to your partner or have a strong support system around you. You should think from all aspects before making a final decision for you and your baby.

references

https://www.yorkhospitals.nhs.uk/seecmsfile/?id=137

https://www.nhs.uk/pregnancy/your-pregnancy-care/screening-for-downs-edwards-pataus-syndrome/

https://www.liverpoolwomens.nhs.uk/media/1941/the-quadruple-screening-test.pdf

https://www.qmul.ac.uk/wolfson/services/antenatal-screening/screening-tests/quadruple-test/