FISH - Trisomy 18 / Edward Syndrome Test
Short Name: FISH Trisomy 18
Also known as: Edward Syndrome FISH, Chromosome 18 FISH, Trisomy 18 FISH Test
FISH - Trisomy 18 / Edward Syndrome Test test available at DNA Labs India for ₹6,000. Uses Fluorescence In Situ Hybridization (FISH) on Amniotic fluid, Chorionic villus sample (CVS), or Peripheral blood samples. Results in Results are typically available within 7 days after the sample reaches the laboratory.. Free home collection in 300+ cities across India.
🩺 Medically Reviewed By
Dr SHAILAJA RAGHUNATH MURDESHWAR
Consultant Physician · Reg: 8052
Last reviewed: September 7, 2026
Overview
The primary purpose of the FISH Trisomy 18 test is to confirm or rule out the presence of an extra copy of chromosome 18 in fetal or newborn cells. This helps in diagnosing Edward Syndrome, guiding prenatal counseling, and assisting parents and clinicians in making informed decisions about pregnancy management and postnatal care.
- Test Code
- 6279
- CPT Code
- 88271
- ICD Code
- Q91.3
- Price
- ₹6,000
- Sample Type
- Amniotic fluid, Chorionic villus sample (CVS), or Peripheral blood
- Result Time
- Results are typically available within 7 days after the sample reaches the laboratory.
- Fasting Required
- No
- Method
- Fluorescence In Situ Hybridization (FISH)
Sample Collection
Duly filled Chromosome & FISH analysis Requisition Form (Form 17) and Prenatal Genetic Testing Consent Form (Form 18) are mandatory. No fasting required.
Method: Venipuncture or amniocentesis/CVS by specialist
Laboratory Analysis
For prenatal samples, a specialist will perform amniocentesis or CVS under ultrasound guidance. For blood samples, a standard venipuncture will be performed.
Report Delivery
No specific precautions. Patients can resume normal activities immediately.
Timeline: Results are typically available within 7 days after the sample reaches the laboratory.
Patient Instructions
About This Test
Who Should Get This Test
The primary purpose of the FISH Trisomy 18 test is to confirm or rule out the presence of an extra copy of chromosome 18 in fetal or newborn cells. This helps in diagnosing Edward Syndrome, guiding prenatal counseling, and assisting parents and clinicians in making informed decisions about pregnancy management and postnatal care.
How to Prepare
- Ensure the requisition form is completely filled and signed
- For prenatal samples, the procedure must be performed by a qualified obstetrician
- Samples should be transported to the laboratory at room temperature within 48 hours
- Do not refrigerate or freeze the sample
Doctor's Notes
Reviewed by Dr SHAILAJA RAGHUNATH MURDESHWAR — MBBS, MD (General Medicine) · Reg. No. 8052
"Early detection of Trisomy 18 is crucial for parental counseling and management. FISH provides rapid results, aiding timely decisions."
Last medically reviewed: September 7, 2026
Test Parameters & Specifications
Sample Stability
- Hemolyzed or clotted blood samples
- Insufficient sample volume
- Incorrect sample container
- Samples without proper requisition forms
- Samples exposed to extreme temperatures
Understanding Your Results
Normal (2 copies)
No evidence of Trisomy 18. The risk of Edward Syndrome is significantly reduced.
Clinical action: Continue routine prenatal care; consider further testing if clinically indicated.
Abnormal (3 copies)
Trisomy 18 confirmed. This is a severe chromosomal disorder with high morbidity and mortality.
Clinical action: Genetic counseling, discussion of pregnancy options, and planning for postnatal care.
Consult your doctor if you have any risk factors for Trisomy 18, such as abnormal ultrasound findings, positive screening tests, or a family history of chromosomal abnormalities. Early consultation can help in timely diagnosis and management.
Limitations
- ⚠FISH detects only targeted chromosomal abnormalities (Trisomy 18) and does not detect other chromosomal imbalances
- ⚠Results should be confirmed by conventional karyotyping or chromosomal microarray analysis
- ⚠Not suitable for detecting mosaicism below the detection threshold
- ⚠Requires specialized laboratory equipment and trained personnel
Risks & Considerations
- ●For amniocentesis/CVS: small risk of miscarriage (0.1-0.3%)
- ●Bleeding or infection at the puncture site
- ●Discomfort or cramping during or after the procedure
Interfering Factors
- ●Maternal cell contamination in prenatal samples
- ●Insufficient cell count or poor sample quality
- ●Inappropriate sample handling or transport delays
- ●Recent blood transfusion (for postnatal blood samples)
Compare With Similar Tests
| Test | FISH - Trisomy 18 / Edward Syndrome Test | FISH | Karyotyping |
|---|---|---|---|
| Comparison | FISH - Trisomy 18 / Edward Syndrome Test |
Frequently Asked Questions
What is the cost of the FISH Trisomy 18 test?
What is the turnaround time for results?
Is fasting required before the test?
What sample is needed for the FISH Trisomy 18 test?
How accurate is the FISH test for Trisomy 18?
Can the FISH test be done during pregnancy?
What does a positive FISH result mean?
Are there any risks associated with the test?
Do I need a doctor's prescription for this test?
Is home sample collection available?
Can the FISH test detect other chromosomal abnormalities?
What is the difference between FISH and karyotyping?
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₹7,371Reference Laboratory Services
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