You are four months pregnant and your doctor has asked for a blood test called the quadruple marker. Perhaps you missed the first-trimester screening, or your doctor wants a second look. Either way, you want to know what it checks and how worried to be about the result.
The quadruple marker test is a routine screening blood test in the second trimester. Most results are reassuring. This guide explains what it measures, when it must be done, how it compares with the older triple marker test, and how to read the result calmly.
Our gynaecology department in Sonipat runs the test in its NABL-accredited laboratory, and the doctor who explains it also performs your pregnancy scans.
What the quadruple marker test measures
The test measures four substances in the mother's blood. They come from the baby, the placenta and the mother's own body. Together with your age, weight and exact pregnancy weeks, their levels estimate the chance of certain conditions.
The four markers are:
- AFP (alpha-fetoprotein), a protein made by the baby.
- hCG, the pregnancy hormone.
- Estriol, a hormone made by the baby and the placenta.
- Inhibin A, a hormone made by the placenta.
The test screens for:
- Down syndrome (trisomy 21)
- Edwards syndrome (trisomy 18)
- Open neural tube defects, such as spina bifida, where the baby's spine does not close fully. AFP is the marker that helps here.
When it is done
The quadruple marker test is done between 15 and 20 weeks of pregnancy. The exact weeks matter, because each marker changes as the pregnancy grows. The lab uses the dates from your early scan to read the result correctly.
If you had the first-trimester screening, the double marker test with the NT scan, your doctor may still suggest the quadruple test for the neural tube check, or to combine both results. If you missed the first-trimester window, the quadruple test is the screening option now.
It sits just before the detailed anomaly scan at 18 to 22 weeks. Our list of scans during pregnancy shows the full schedule.
Quadruple marker vs triple marker test
The triple marker test measures three of the four substances: AFP, hCG and estriol. It does not include inhibin A.
Adding inhibin A makes the quadruple test better at picking up Down syndrome, with fewer false alarms. That is why most doctors now prefer the quadruple test. The triple test is still offered in some places.
At our laboratory the current prices are ₹3,000 for the quadruple marker and ₹2,200 for the triple marker, as listed on our tests page.
How to read the result
The result is written as a chance, such as "1 in 3,000" or "1 in 200", for each condition.
- A low-chance result means the chance is below the lab's cut-off. It is reassuring, but no screening test can promise that a baby is unaffected.
- A high-chance result means the chance is above the cut-off. It does not mean the baby has the condition. Most women with a high-chance result go on to have a baby without it.
A raised AFP has some common, harmless explanations. The pregnancy may be further along than thought, or there may be twins. That is one reason the dates from your early scan matter so much.
If the result is high chance
Your doctor will talk you through the options. Nothing needs to be decided in a rush.
- A detailed anomaly scan looks closely at the baby's spine, brain and heart, and is very good at finding neural tube defects.
- A cell-free DNA blood test is a more accurate screening test for chromosomal conditions.
- A diagnostic test, such as amniocentesis, gives a definite answer but carries a small risk of miscarriage.
- You may also choose not to test further.
The NHS guide to screening for Down's, Edwards' and Patau's syndromes and the ACOG guide to prenatal genetic screening tests explain these choices in the same careful way.
On the day of the test
The quadruple marker is a simple blood test from a vein in your arm. There is nothing special to do beforehand.
- Come any time during sample collection hours. You do not need to fast.
- Bring your dating scan report. The lab needs your exact pregnancy weeks on the day the blood is taken.
- Tell the staff your current weight, and whether you have diabetes, are carrying twins, or conceived through IVF. Each of these changes how the markers are read.
The result takes a little longer than a routine blood test, because the chance calculation combines all four markers with your details. Your doctor will tell you when to expect it, and will go through it with you rather than leaving you to read a report alone.
A word on folic acid
Folic acid taken before and in early pregnancy lowers the chance of neural tube defects. If you are reading this while planning a pregnancy, ask your doctor about starting it now. It is one of the simplest and most effective steps in antenatal care.
A word on the law
Sex determination is illegal in India. Our obstetric ultrasound is PC-PNDT compliant. No test or scan here will reveal the sex of your baby, and staff are legally obliged to refuse the question. Please do not ask.
Care at Saroj Hospital
Dr. Deepa Aggarwal, MBBS, DGO, DMRD, DNB (Radiology) sees patients in the gynaecology OPD every day, 10:00 AM–2:00 PM and 5:00–7:00 PM.
She is qualified in both obstetrics and radiology. If your quadruple marker result needs a closer look, the same doctor who explains it can perform the detailed scan, without sending you between departments. When the third trimester comes, our guide to the 8 month pregnancy scan explains what is checked next.
Frequently asked questions
Do I need to fast for the quadruple marker test?
No. You can eat and drink normally. Bring your early dating scan report so the lab uses your exact pregnancy weeks.
Can I have the quadruple test after 20 weeks?
Its accuracy falls outside the 15 to 20 week window. If you have passed 20 weeks, talk to your doctor about the anomaly scan and other options instead.
Is the quadruple marker test the same as the anomaly scan?
No. The quadruple test is a blood test that estimates chance. The anomaly scan is a detailed ultrasound that looks directly at the baby. They work best together.
Is the quadruple marker test compulsory?
No. It is offered to pregnant women, and most choose to have it, but the choice is yours. Your doctor will explain what it can and cannot tell you.
Book an appointment
If you are between 15 and 20 weeks and have not had screening yet, book soon so the test falls inside the right window. The blood test, the scan and the doctor who explains them are all in one place.
Book an appointment with the gynaecology OPD, or call reception on +91 96676 67011.
Medically reviewed by Dr. Deepa Aggarwal, MBBS, DGO, DMRD, DNB (Radiology), Saroj Hospital, Sonipat.
This article is general health information, not medical advice. For guidance about your own health, please consult a doctor.
Consult Dr. Deepa Aggarwal
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