Prenatal screening explained
NIPT vs double marker test: which prenatal screen?
Both screen for chromosomal conditions early in pregnancy — but they differ in accuracy and what they involve. Here’s a clear, calm comparison so you can choose the right screen with your doctor.
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The short answer
The double marker test is a first-trimester blood test, usually combined with the NT scan, that gives a risk estimate for common chromosomal conditions. NIPT (non-invasive prenatal testing) analyses cell-free fetal DNA in the mother’s blood and is a more accurate screen for the common trisomies. Both are screening tests — not diagnostic — and a high-risk result is confirmed with a diagnostic test.
NIPT vs double marker at a glance
| Feature | Double marker | NIPT |
|---|---|---|
| What it is | Blood test + NT scan (combined screen) | Cell-free fetal DNA blood test |
| Timing | ~11–14 weeks | From ~10 weeks |
| Accuracy | Good screening estimate | Higher detection for common trisomies |
| Result | Risk estimate | Higher-precision risk |
| Diagnostic? | No (screening) | No (screening) |
When each is recommended
The double marker (as part of combined first-trimester screening with the NT scan) is a widely used, accessible option. NIPT offers higher detection for the common trisomies and may be preferred based on your history, age or a previous result. There is no single “right” screen for everyone — the appropriate choice depends on your individual circumstances, which your doctor will discuss with you. See the full picture on our prenatal screening page.
Screening vs diagnostic — what a result means
This is the key point: both NIPT and the double marker are screening tests. They estimate the chance of a condition; they do not diagnose it. A low-risk result is reassuring but not a guarantee, and a high-risk result does not mean the baby is affected — it means a diagnostic test (such as CVS or amniocentesis) is offered to confirm. Our fetal-medicine procedures page explains those next steps.
How it fits your scan schedule
Screening sits alongside your routine scans. The NT scan at 11–14 weeks checks more than chromosomes, so it remains valuable even if you choose NIPT. Later, the anomaly scan reviews the baby’s anatomy. Our fetal-medicine team coordinates the timing so nothing is missed.
Choosing without pressure
We explain the options, the accuracy and the limits of each, and help you decide what fits your pregnancy and your preferences — calmly and without pressure. Imaging follows the ISUOG protocol, and care is led by our fetal-medicine team alongside Dr. Priyadatt Patel.
Planning your prenatal screening?
Talk to us about which screen suits your pregnancy — clear guidance, no pressure.
WhatsApp +91 97234 31544 Contact & directionsFrequently asked questions
Is NIPT better than the double marker?
Are they diagnostic tests?
When is NIPT done?
Do I still need the NT scan?
Which should I choose?
Medically reviewed by Dr. Priyadatt Patel — Senior Gynecologist · Advanced Laparoscopic Surgeon · IVF and Endometriosis Programme Lead, Advanced Laparoscopic Surgeon & IVF and Endometriosis Programme Lead. Last reviewed June 2026. This page provides general clinical orientation only and is not a substitute for personal medical advice; no outcome is guaranteed.
Dr. Priyadatt Patel
Senior Gynecologist · Advanced Laparoscopic Surgeon · IVF and Endometriosis Programme Lead
MS OBGyn · Pregnancy Care · Advanced Gynaecological Ultrasound · Fertility Preservation
ESHRE / ESGE / AAGL / ASRM guideline-aligned practice. 3D Karl Storz precision technique. Fertility-preservation-first philosophy. Evidence-based decisions, honest counselling, long-term outcomes orientation.
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