Maternal Serum Screen 2: Advanced Reflex to Maternal Blood for Fetal DNA (MBFD) Chromosome 21 Test
Short Name: MSS2 with MBFD-21
Also known as: MSS2 MBFD-21 Test, Maternal Blood Fetal DNA Chromosome 21 Test, Non-Invasive Prenatal Testing Chromosome 21, First Trimester Maternal Serum Screen, NIPT Trisomy 21 Screening
Maternal Serum Screen 2: Advanced Reflex to Maternal Blood for Fetal DNA (MBFD) Chromosome 21 Test test available at DNA Labs India for ₹3,500. Uses Chemiluminescent Immunoassay, DNA Sequencing on Serum samples. Results in Dual test (PAPP-A and Free Beta hCG): Same-day report if sample is received Monday through Saturday by 9 AM. MBFD-21 reflex analysis: Report available by the following Tuesday if sample is received Tuesday by 9 AM.. Free home collection in 300+ cities across India.
🩺 Medically Reviewed By
Dr SULOCHANA HEMCHANDRA HOLLA
Consultant Medical Geneticist · Reg: 8532
Last reviewed: September 7, 2026
Overview
The purpose of this test is to screen for the risk of Down syndrome (Trisomy 21) during the first trimester of pregnancy by measuring PAPP-A and Free Beta hCG levels in maternal serum, and reflexing to cell-free fetal DNA analysis when indicated. It enables early identification of pregnancies at increased risk for chromosomal abnormalities, facilitating timely counselling and appropriate clinical decision-making.
- Test Code
- 1214
- Price
- ₹3,500
- Sample Type
- Serum
- Result Time
- Dual test (PAPP-A and Free Beta hCG): Same-day report if sample is received Monday through Saturday by 9 AM. MBFD-21 reflex analysis: Report available by the following Tuesday if sample is received Tuesday by 9 AM.
- Fasting Required
- No
- Method
- Chemiluminescent Immunoassay, DNA Sequencing
Sample Collection
Provide maternal date of birth (dd/mm/yy); LMP date or ultrasound-determined gestational age; number of fetuses (single/twins); diabetic status; body weight in kg; IVF status; smoking history; and any previous history of Trisomy 21 pregnancy. No fasting is required. Ensure the sample is collected within the valid gestational window of 10–13 weeks.
Method: Venipuncture
Laboratory Analysis
A standard venipuncture will be performed to collect 3 mL (minimum 1.5 mL) of blood into a Serum Separator Tube (SST). The procedure is quick and poses no risk to the mother or fetus. Inform the phlebotomist of all relevant clinical details at the time of collection.
Report Delivery
The serum sample is stored and shipped refrigerated or frozen. If the initial screen result is positive, a follow-up sample of 10 mL whole blood in a special MBFD-21/NIPT tube (available from LPL) must be submitted along with the duly filled Maternal Serum Screen 2 reflex to MBFD-21 consent form (Form 12). This second sample should be shipped refrigerated and must NOT be frozen. Reports will be available as per the specified turnaround time.
Timeline: Dual test (PAPP-A and Free Beta hCG): Same-day report if sample is received Monday through Saturday by 9 AM. MBFD-21 reflex analysis: Report available by the following Tuesday if sample is received Tuesday by 9 AM.
Patient Instructions
About This Test
Who Should Get This Test
The purpose of this test is to screen for the risk of Down syndrome (Trisomy 21) during the first trimester of pregnancy by measuring PAPP-A and Free Beta hCG levels in maternal serum, and reflexing to cell-free fetal DNA analysis when indicated. It enables early identification of pregnancies at increased risk for chromosomal abnormalities, facilitating timely counselling and appropriate clinical decision-making.
How to Prepare
- Collect 3 mL (minimum 1.5 mL) venous blood in an SST (Serum Separator Tube)
- Clearly label the tube with maternal details and date of collection
- Provide maternal date of birth, LMP/ultrasound date, number of fetuses, diabetic status, body weight, IVF status, smoking history, and previous Trisomy 21 history
- Ship the serum sample refrigerated or frozen
- For positive reflex results: collect 10 mL whole blood in the special MBFD-21 tube available from LPL
- Submit the filled consent form (Form 12) with the reflex sample
- Ship reflex sample refrigerated; DO NOT FREEZE
- Valid gestational age window: 10–13 weeks
Doctor's Notes
Reviewed by Dr SULOCHANA HEMCHANDRA HOLLA — MBBS, MD (Medical Genetics) · Reg. No. 8532
"The MSS2 with advanced reflex to MBFD-21 is a valuable first-trimester screening tool. It combines traditional biochemical markers (PAPP-A and Free Beta hCG) with cell-free fetal DNA analysis to provide a highly sensitive risk assessment for Trisomy 21. I recommend this test to all my pregnant patients between 10 and 13 weeks of gestation. A positive result does not confirm Down syndrome but indicates the need for further confirmatory diagnostic testing such as amniocentesis or CVS. Early screening empowers parents to make informed decisions and plan appropriate follow-up care."
Last medically reviewed: September 7, 2026
Test Parameters & Specifications
Sample Stability
- Sample collected outside the 10–13 week gestational window
- Hemolyzed or grossly lipemic serum sample
- Insufficient sample volume (less than 1.5 mL)
- Missing or incomplete maternal clinical information (date of birth, gestational age, etc.)
- Frozen reflex sample (MBFD-21 follow-up samples must not be frozen)
- Missing consent form (Form 12) for reflex testing
Understanding Your Results
Low Risk (Trisomy 21 risk < 1 in 250)
The screening result suggests a low probability of Down syndrome. No reflex MBFD-21 testing is typically triggered. Routine prenatal care should continue.
Action: Continue standard prenatal monitoring as advised by your obstetrician.
High Risk (Trisomy 21 risk ≥ 1 in 250)
The screening result indicates an elevated risk for Down syndrome. The test will automatically reflex to MBFD-21 cell-free fetal DNA analysis for further evaluation.
Action: Await MBFD-21 reflex results. Genetic counselling is recommended. Discuss confirmatory diagnostic testing (CVS or amniocentesis) with your doctor.
MBFD-21 Negative (No Aneuploidy Detected)
The cell-free fetal DNA analysis did not detect an extra copy of chromosome 21. The likelihood of Down syndrome is significantly reduced.
Action: Low likelihood of Trisomy 21. Continue routine prenatal care. Discuss results with your healthcare provider.
MBFD-21 Positive (Aneuploidy Detected)
The cell-free fetal DNA analysis detected a pattern consistent with Trisomy 21. This is a screening result and not a definitive diagnosis.
Action: Confirmatory diagnostic testing such as chorionic villus sampling (CVS) or amniocentesis is strongly recommended. Seek genetic counselling promptly.
You should consult your obstetrician or a genetic counsellor if your MSS2 or MBFD-21 result is positive or high risk, if you have a family history of chromosomal abnormalities, if you are unsure about how to interpret your results, or if you wish to understand your options for confirmatory diagnostic testing such as CVS or amniocentesis.
Limitations
- ⚠This is a screening test, not a diagnostic test; false positives and false negatives can occur
- ⚠The MBFD-21 reflex component is performed only if the initial dual marker screen is positive or borderline
- ⚠May not detect all cases of Trisomy 21, particularly if fetal DNA fraction is low
- ⚠Does not screen for all chromosomal or genetic conditions
- ⚠Results should always be interpreted by a qualified healthcare provider in the context of clinical history
- ⚠Not validated for gestational ages outside 10–13 weeks
Risks & Considerations
- ●Minor bruising or discomfort at the venipuncture site
- ●Rare risk of fainting during blood draw
- ●No risk to the fetus as this is a non-invasive maternal blood test
- ●Psychological anxiety associated with awaiting screening results
- ●Small possibility of false-positive or false-negative results
Interfering Factors
- ●Incorrect gestational age estimation may affect marker levels and risk calculation
- ●Multiple pregnancies (twins or more) require specific adjustments and may alter results
- ●Maternal weight can influence marker concentrations
- ●IVF pregnancies may have different baseline marker levels
- ●Maternal smoking and diabetic status may affect biochemical marker levels
- ●Hemolyzed or lipemic serum samples may interfere with immunoassay results
Compare With Similar Tests
| Test | Maternal Serum Screen 2: Advanced Reflex to Maternal Blood for Fetal DNA (MBFD) Chromosome 21 Test | Dual Marker Test | NIPT (Non-Invasive Prenatal Testing) | Combined First Trimester Screening (FTS) | Amniocentesis / CVS |
|---|---|---|---|---|---|
| Comparison | Maternal Serum Screen 2: Advanced Reflex to Maternal Blood for Fetal DNA (MBFD) Chromosome 21 Test | The Dual Marker test measures PAPP-A and Free Beta hCG but does not include reflex fetal DNA analysis. The MSS2 with MBFD-21 adds a second layer of screening via cfDNA sequencing for more accurate risk stratification. | Standalone NIPT directly analyses cell-free fetal DNA for multiple chromosomal conditions. The MSS2 with MBFD-21 uses a reflex model, performing cfDNA analysis only when the initial biochemical screen is positive, making it a cost-effective approach. | FTS combines biochemical markers with nuchal translucency (NT) ultrasound. The MSS2 with MBFD-21 replaces NT measurement with reflex cfDNA analysis, offering a blood-only screening option. | These are invasive diagnostic tests that provide definitive chromosomal analysis. They carry a small procedural risk. The MSS2 with MBFD-21 is non-invasive and used for risk assessment, not definitive diagnosis. |
Frequently Asked Questions
What is the MSS2 with MBFD Chromosome 21 test?
When should this test be done during pregnancy?
Is the MSS2 MBFD-21 test a diagnostic test?
How is the test performed?
Is fasting required for this test?
What does a positive MBFD-21 result mean?
What does a negative MBFD-21 result mean?
Is this test safe for the baby?
What is the cost of the MSS2 MBFD-21 test in India?
What information do I need to provide before the test?
What happens if my initial screening result is positive?
In which cities is home sample collection available for this test?
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