What is the double marker test?
In short
- The double marker test is a blood test that measures two substances to estimate the chance of Down's syndrome and similar conditions.
- In Indian practice, it's usually done between 11 and 13 weeks, often together with the NT ultrasound scan.
- Like all these tests, it gives you a chance, not a yes/no diagnosis.
- Your doctor will explain your result and whether a further, diagnostic test is offered.
What happens
- A blood sample is taken from your arm, usually at the same visit as your NT scan.
- The lab measures two markers in your blood — free beta-hCG and PAPP-A — and combines the result with the NT measurement and your age.
- You get back a chance, for example 1 in 500, not a pass/fail result.
The details: numbers and where they differ
Where this test comes from
The double marker test is standard obstetric practice in India, but this page could not find a single MoHFW or ICMR national guideline that names its exact timing — the 11-to-13-week window below comes from peer-reviewed Indian obstetric literature, not a government protocol.
The numbers
| Measure | Value | Source |
|---|---|---|
| Double marker (dual marker) test window, India (pregnant women, India) | 11–13 weeks gestation | Peer-reviewed Indian obstetric literature (PMC-hosted) |
When to call your doctor
- If you're not sure whether you've been offered this test or when it's scheduled.
- If your result comes back higher chance and you want to discuss further, diagnostic testing.
Discuss your results with your doctor: this page reports what these sources say, not advice for your situation.
Sources
- Peer-reviewed Indian obstetric literature (PMC-hosted), Down's Syndrome Screening in the First Trimester with Additional Serum Markers: Indian Parameters. Named as the guideline this section describes; its text and tables are not reproduced here (Journal article; licence not confirmed (cite only)). Describes the double marker (dual marker) test, usually done between 11 and 13 weeks, measuring free beta-hCG and PAPP-A to estimate the chance of Down's syndrome and similar conditions.
Sources checked 2026-09-26. How we source and check every page.
Educational summary of named sources, not medical advice.