Screening and tests
NT Scan vs Double Marker Test: What's the Difference?
The NT scan is an ultrasound and the double marker is a blood test. Learn how doctors read the two together in first-trimester screening.
Reviewed23 October 20266 min read
Down's Screening (OSCAR)
A combined first trimester screening that assesses the chance of Down's syndrome and other chromosomal conditions.
11 to 14 weeksScreening Scans
Timing
Usually between 11 and 13+6 weeks of pregnancy.
Preparation
No special preparation is needed.
OSCAR is a combined first trimester screening that brings together a detailed ultrasound measurement of your baby and a simple blood test from the mother.
The result is expressed as a chance or risk figure, which the doctor explains clearly. It is a screening test, not a diagnosis, and a high chance result does not mean your baby definitely has a condition.
What it checks
- The fluid space at the back of the baby's neck (nuchal translucency)
- Scan markers such as the baby's nasal bone
- Two markers measured in a blood sample from the mother
- A combined chance figure, explained to you in person
Who is it for
- Any pregnancy wanting first trimester screening
- Women who will be 35 or over at delivery
- Anyone with a previous pregnancy or family history of a chromosomal condition
What to expect on the day
- 1
A detailed ultrasound measures the baby and the nuchal translucency.
- 2
A small blood sample is taken from the mother's arm.
- 3
The scan and blood results are combined into a chance figure.
- 4
The specialist explains what the figure means for your pregnancy.
A detailed ultrasound measures the baby and the nuchal translucency.
A small blood sample is taken from the mother's arm.
The scan and blood results are combined into a chance figure.
The specialist explains what the figure means for your pregnancy.
Preparation
When: Usually between 11 and 13+6 weeks of pregnancy.
No special preparation is needed.
Your report and next steps
Your combined result is explained in the same visit. If the chance is low, the usual next step is the anomaly scan between 18 and 22 weeks. If the chance is higher, our in-house counselling helps you understand options such as NIPT or diagnostic testing.
Your doctors
Common questions
Down's Screening (OSCAR)11 to 14 weeks
Related guides
Related guides
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In keeping with the PCPNDT Act, 1994, this service does not involve determination or disclosure of the sex of the fetus. This is a criminal offence in India and is never performed at this centre.
Book your appointment
Call us, message us on WhatsApp, or send a request and our team will call you back to schedule your visit.
Mon - Fri: 9:00 AM - 9:00 PM