Apollo Diagnostics | NABL-Certified Lab | No Fasting Required | USG Report & Doctor's Prescription Required
What is a Dual Marker Test?
The Dual Marker Test (also called the Double Marker Test) is a vital first trimester prenatal screening conducted between 11 and 14 weeks of pregnancy. It measures two specific biochemical markers in the mother's blood — Free Beta-HCG and PAPP-A (Pregnancy-Associated Plasma Protein-A) — and combines these values with the mother's age, gestational age and Nuchal Translucency (NT) ultrasound measurement to calculate the statistical risk of chromosomal abnormalities in the developing baby. It is a predictive tool, not a diagnostic test.
⚠ Important — bring these to your appointment:
- Your latest ultrasound (USG) report — especially the NT measurement and Crown-Rump Length (CRL)
- Your gynaecologist's prescription or referral
- Your exact date of birth (maternal age is a key calculation variable)
- Your LMP (Last Menstrual Period) date
What Does the Dual Marker Test Measure?
The two blood markers measure different aspects of placental and fetal function:
- Free Beta-HCG (Human Chorionic Gonadotropin) — produced by the placenta. In Down Syndrome (Trisomy 21) free beta-HCG is typically elevated (above 2.0 MoM). In Edwards Syndrome (Trisomy 18) and Patau Syndrome (Trisomy 13) it is typically low.
- PAPP-A (Pregnancy-Associated Plasma Protein-A) — produced by the placenta. In chromosomal abnormalities (especially Trisomy 21, 18 and 13) PAPP-A is typically low (below 0.4 MoM). Low PAPP-A also correlates with increased risk of placental insufficiency and pre-eclampsia.
- MoM (Multiples of the Median) — both markers are expressed as MoM values — the ratio of the patient's measured value to the expected median for that gestational age. The risk calculation software uses MoM values rather than absolute levels.
Why is the Dual Marker Test Essential?
This screening is part of a combined first trimester assessment:
- Chromosomal Screening — assesses the statistical probability of Down Syndrome (Trisomy 21), Edwards Syndrome (Trisomy 18) and Patau Syndrome (Trisomy 13)
- Non-Invasive & Safe — a simple blood test with zero risk to mother or baby
- Early Detection — identifying high-risk pregnancies in the first trimester allows time for further testing (NIPT or amniocentesis) and informed decision-making
- NT Scan Correlation — for highest accuracy the Dual Marker blood results are combined with the NT (Nuchal Translucency) ultrasound measurement in a computer algorithm to generate the final combined risk ratio
- Pre-eclampsia Risk Assessment — low PAPP-A alongside other markers can predict risk of early-onset pre-eclampsia
How the Combined Risk Ratio is Calculated
The Dual Marker is most powerful as part of the First Trimester Combined Screen:
- Components: Maternal age + Free Beta-HCG MoM + PAPP-A MoM + NT measurement (from USG) + CRL (Crown-Rump Length)
- Output: A risk ratio such as 1:250 (meaning 1 in 250 chance) for each condition screened
- Cut-offs: Risk above 1:250 (or 1:150 in some protocols) for Trisomy 21 is considered high-risk. Risk above 1:100 for Trisomy 18/13 is high-risk.
- Detection rate: First trimester combined screening (Dual Marker + NT) detects approximately 85–90% of Down Syndrome cases.
- Why NT measurement is critical: The NT ultrasound must be performed by a certified FMF (Fetal Medicine Foundation) sonologist at 11–13+6 weeks. Bring the NT measurement report when submitting blood for the Dual Marker.
Dual Marker Results — Low Risk vs High Risk
| Result | Interpretation | Recommended Next Step |
|---|---|---|
| Low Risk (e.g. 1:1000 or lower) | Low probability of the screened chromosomal condition in this pregnancy | Continue routine antenatal care. Anomaly scan at 18–20 weeks. |
| Intermediate Risk (1:101 to 1:250) | Elevated probability — further evaluation recommended | Discuss NIPT or invasive testing with your gynaecologist |
| High Risk (1:100 or above) | High probability of chromosomal abnormality | Urgent referral for NIPT (non-invasive) or amniocentesis/CVS (diagnostic) for confirmation |
A high-risk Dual Marker result is not a diagnosis — it means further confirmatory testing is needed. A low-risk result significantly reduces the likelihood but does not eliminate the possibility. Discuss your result with your gynaecologist before making any decision.
When Should the Dual Marker Test Be Done?
The Dual Marker test must be performed between 11 weeks and 13 weeks 6 days of gestation. Outside this window the marker levels change significantly and the risk calculation becomes inaccurate. The NT ultrasound must also be performed within this same window. Missing this window means switching to second trimester screening options (Triple Marker at 15–20 weeks).
Who Should Get a Dual Marker Test?
- All pregnant women in the first trimester as a routine prenatal screen
- Women of Advanced Maternal Age (35 and above) — age-related chromosomal risk increases significantly
- Women with a previous chromosomally abnormal pregnancy
- Women with a family history of Down Syndrome or other chromosomal conditions
- Women with IVF pregnancies
- Women with abnormal NT measurement on ultrasound
Dual Marker Test Price in Kolkata
Dual Marker (Double Marker) Test Price: ₹2,750
No fasting required | USG report & prescription mandatory | 11–14 weeks gestational window | Results in 24–48 hours
No fasting required | USG report & prescription mandatory | 11–14 weeks gestational window | Results in 24–48 hours
Prenatal Screening Pathway — Where Dual Marker Fits
- 10–13 weeks: NT Scan — Nuchal Translucency ultrasound by certified sonologist (before or alongside Dual Marker blood collection)
- 11–13 weeks: Dual Marker blood test — Free Beta-HCG + PAPP-A (this test)
- Combined Risk Report — risk ratio generated by combining NT + Dual Marker + maternal age
- If high-risk: NIPT or amniocentesis — NIPT is non-invasive (10+ weeks); amniocentesis is diagnostic (15–20 weeks)
- 18–20 weeks: Anomaly Scan (Level 2 USG) — detailed structural survey of the fetus for all pregnancies
- 15–20 weeks: Triple Marker — second trimester alternative if Dual Marker window was missed
Home Collection for Dual Marker Test in Kolkata
Apollo Diagnostics provides home blood sample collection for the Dual Marker test across Nagerbazar, Dum Dum, South Dum Dum and surrounding North and Central Kolkata areas. Please ensure you have your NT ultrasound report and gynaecologist's prescription ready at the time of home collection — these are required for accurate risk calculation and cannot be submitted later.
- Home collection available: 7:00 AM – 2:30 PM Daily
- No fasting required
- NT USG report and prescription mandatory at time of collection
- Must be within 11–13+6 weeks gestation
- Results in 24–48 hours
- Free home collection on orders above ₹2,000
Quick Links
→ Apollo Diagnostics Nagerbazar → Full List of Individual Tests → Book Home Collection → Full Body Checkup Packages
→ Apollo Diagnostics Nagerbazar → Full List of Individual Tests → Book Home Collection → Full Body Checkup Packages
Frequently Asked Questions
Q1. What is the Dual Marker test used for?
The Dual Marker test measures Free Beta-HCG and PAPP-A in maternal blood between 11–14 weeks of pregnancy. Combined with the NT ultrasound measurement and maternal age, it calculates the statistical risk of Down Syndrome (Trisomy 21), Edwards Syndrome (Trisomy 18) and Patau Syndrome (Trisomy 13). It is a standard first trimester prenatal screening test recommended for all pregnant women.
Q2. When should the Dual Marker test be done?
The Dual Marker test must be done between 11 weeks and 13 weeks 6 days of gestation. Outside this window marker levels change significantly and the risk calculation becomes unreliable. The NT ultrasound must also be performed within this same window. If this window is missed, the Triple Marker test at 15–20 weeks is the alternative second trimester screen.
Q3. Does the Dual Marker test require fasting?
No. The Dual Marker test does not require fasting. Blood can be collected at any time of day. However you must bring your latest NT ultrasound report (with NT measurement and CRL) and your gynaecologist's prescription at the time of collection — these are mandatory for accurate risk calculation.
Q4. What is the Dual Marker test price at Apollo Diagnostics Kolkata?
The Dual Marker (Double Marker) test price at Apollo Diagnostics is ₹2,750. No fasting required. Results are available in 24–48 hours. Home collection is available free on orders above ₹2,000.
Q5. What does a high-risk Dual Marker result mean?
A high-risk result means the calculated probability of a chromosomal abnormality is above the cut-off threshold (typically 1:250 for Trisomy 21 and 1:100 for Trisomy 18/13). It does not mean your baby has a chromosomal condition — it means the risk is elevated and further testing is recommended. Your next step is to discuss the result with your gynaecologist who will advise NIPT (non-invasive, above 99% accuracy) or amniocentesis (diagnostic, 100% accuracy) for confirmation.
Q6. What is the difference between Dual Marker and Triple Marker tests?
The Dual Marker (Double Marker) is a first trimester test performed at 11–14 weeks measuring Free Beta-HCG and PAPP-A. It is combined with the NT ultrasound for a detection rate of about 85–90% for Down Syndrome. The Triple Marker is a second trimester test performed at 15–20 weeks measuring AFP, HCG and Estriol — without an NT ultrasound component. The Triple Marker has a slightly lower detection rate (about 70–75% for Trisomy 21) but is the only option if the first trimester window is missed. Do both if possible; the Dual Marker is the preferred first choice.
Q7. Do I need the NT scan before doing the Dual Marker blood test?
Yes. The NT (Nuchal Translucency) ultrasound measurement is a required input for the combined risk calculation. The Dual Marker blood results alone without the NT measurement produce an incomplete and less accurate risk estimate. Ideally the NT scan should be done on the same day as or within a few days of the blood collection, both within the 11–13+6 week window. Bring the printed NT scan report to your blood collection appointment.
Q8. Is home collection available for Dual Marker test in Kolkata?
Yes. Apollo Diagnostics provides home blood collection for Dual Marker tests across Nagerbazar, Dum Dum, South Dum Dum, Amarpalli, Motijheel, Satgachi, Teghoria, Chinar Park, Rajarhat, Baguiati, Lake Town, Bangur, Kaikhali, Sealdah, Entally, Phoolbagan, Tangra and surrounding areas. Please have your NT USG report and prescription ready. Book by calling or WhatsApping +91 8660434628.
Q9. How long does it take to get Dual Marker test results?
Dual Marker test results are typically available within 24–48 hours of sample collection. Digital reports are delivered to your WhatsApp or email and can be shared directly with your gynaecologist.
Q10. Which centre processes my Dual Marker sample in Kolkata?
All samples collected across North and Central Kolkata are processed at Apollo Diagnostics Nagerbazar — Nandarani Apartment, 8A Narasingha Avenue, Nagerbazar, Dum Dum, Kolkata 700074. Our lab is NABL-certified and ISO-certified.
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