Obstetrics• Updated 21 October 2026
Double Marker Test
A first-trimester blood test, combined with the NT scan, that estimates the chance of Down syndrome and some other conditions.
Results: A few days Specimen: Blood
Quick Summary
Primary Purpose
To screen for chromosomal conditions between 11 and 14 weeks.
What It Measures
PAPP-A and free beta-hCG, combined with NT and age.
Preparation
No preparation.
Overview
It gives a risk estimate, not a diagnosis.
High-chance results are followed by NIPT or diagnostic tests.
What It Measures
PAPP-A and beta-hCG
Pregnancy hormones.
How It's Performed
- 01
Timing
With the NT scan.
- 02
Blood sample
From a vein.
- 03
Result
Combined risk calculated.
Interpreting Results & Next Steps
Discuss with Doctor
Your doctor will explain what your result means and what happens next.
If values are High:
A higher-chance result needs counselling about further tests.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Down Syndrome Tests(opens in a new tab) · MedlinePlus, US National Library of Medicine
- 12-week scan(opens in a new tab) · NHS