FISH-Neonatal Screen (2 Probes Trisomy) Test: Booking, Price, and Results
About FISH-Neonatal Screen (2 Probes Trisomy) Test: Booking, Price, and Results
| Field | Value |
|---|---|
| Also Known As | Neonatal aneuploidy detection FISH, FISH trisomy screen (Neonatal), Newborn chromosome FISH screen, Interphase FISH aneuploidy test |
| Sample Type | Peripheral blood (sodium heparin tube), cord blood, bone marrow sample, amniotic fluid, or CVS (Chorionic Villus Sampling) |
| Fasting Required | No |
| Report Time | 3 Days |
| Recommended For | Newborns of any gender with suspected chromosomal abnormalities or congenital anomalies |
| Price | Starting at ₹3,000 |
What is a FISH-Neonatal Screen (2 Probes Trisomy) Test?
The FISH-Neonatal screen (2 probes Trisomy) test is a specialised genetic test performed on a newborn's sample to detect extra copies of specific chromosomes. FISH stands for Fluorescence In Situ Hybridisation, a technique that uses fluorescently labelled DNA probes to identify chromosome abnormalities in cells. This test is also known as the Neonatal aneuploidy detection FISH or the FISH trisomy screen (neonatal). It is ordered by a paediatrician or neonatologist when a newborn shows signs that may suggest a chromosomal condition.
What Does a FISH-Neonatal Screen (2 Probes Trisomy) Test Measure?
This test uses two DNA probes to check whether specific chromosomes are present in the normal number of copies. Each probe targets a different chromosome, and the laboratory counts fluorescent signals to determine if extra copies exist.
| Probe Target | What it Checks | Significance |
|---|---|---|
| Chromosome 13 | Number of copies of chromosome 13 in each cell | Detects Patau syndrome (trisomy 13) |
| Chromosome 21 | Number of copies of chromosome 21 in each cell | Detects Down syndrome (trisomy 21) |
A normal result shows two signals per chromosome. Three signals indicate an extra copy, which points to a trisomy condition.
Why is a FISH-Neonatal Screen (2 Probes Trisomy) Test Done?
This test is performed specifically on newborns when physical or clinical signs raise concern about a chromosomal disorder. It provides rapid results so that care can begin without delay.
Common Symptoms That May Require This Test
A doctor may request this FISH-Neonatal screen (2 probes Trisomy) test when a newborn presents with one or more of the following signs:
- Distinctive facial features, such as a flat face or a small head
- Low muscle tone (hypotonia), making the baby feel unusually floppy
- Congenital heart defects identified at birth
- Feeding difficulties or poor weight gain
- Growth restriction or unusually small size
- Extra fingers or toes (polydactyly)
- Clenched hands or other physical malformations
Conditions This Test Can Help Detect
The test screens for trisomies of the two targeted chromosomes. Conditions it can help identify include:
- Down syndrome (trisomy 21), the most common chromosomal cause of intellectual disability, resulting from an extra copy of chromosome 21
- Patau syndrome (trisomy 13), a serious condition causing severe intellectual disability, cleft lip or palate, extra digits, and heart defects
How to Prepare and What to Expect
No special preparation is needed before this test. The process is straightforward and applies to both the newborn and any other indicated sample type.
Do You Need to Fast?
No fasting is required. The sample can be collected at any time, regardless of when the newborn was last fed.
Practical Tips Before Your Test
Keep the following points in mind before sample collection:
- Bring a detailed clinical history, including the newborn's symptoms, birth details, previous test results, and family history, as this is required for the test
- Inform the healthcare team about any medications the newborn is receiving
- Ensure the sample is not frozen or exposed to extreme temperatures before submission
- Use only a sodium heparin (green) tube for peripheral blood collection; other anticoagulants are not acceptable
- Arrange timely transport of the sample to the laboratory, as delays can affect quality
Step-by-Step Procedure
Collection procedures vary depending on the sample type. The Test Details Manual specifies that peripheral blood collection is the only sample type available for home collection; all other sample types require collection at a hospital or clinical centre.
Peripheral Blood (Home Collection or Centre Visit)
- A trained phlebotomist cleans the collection site (typically the heel or a vein in the arm) with an antiseptic.
- A small blood sample of around 3 ml is collected into a green sodium heparin tube.
- The tube is gently inverted several times to mix the blood with the anticoagulant.
- The sample is clearly labelled with the newborn's details and clinical history documentation.
- The sample is stored at 2 to 8°C and transported promptly to the laboratory.
Cord Blood, Bone Marrow, Amniotic Fluid, or CVS (Hospital Collection Only)
- These samples are collected by a qualified specialist in a hospital or clinical setting.
- The relevant procedure (cord blood draw, bone marrow aspiration, amniocentesis, or CVS biopsy) is performed under appropriate clinical conditions.
- Each sample is placed in the correct container as instructed by the laboratory.
- Accurate patient identification and clinical notes accompany the specimen.
- The sample is transported to the cytogenetics laboratory under the recommended storage conditions without freezing.
- In the laboratory, trained technologists analyse at least 50 interphase nuclei per probe set to count chromosomal signals.
Factors That Can Affect Accuracy
Certain conditions can interfere with reliable results. These include:
- Frozen or clotted specimens, which are not acceptable
- Use of anticoagulants other than sodium heparin
- Inadequate blood volume in the sample
- Delayed transport or improper storage temperatures
- Low-level mosaicism (where only some cells carry the extra chromosome), which this test may not detect
Understanding Your FISH-Neonatal Screen (2 Probes Trisomy) Test Results
Results are reported based on the number of fluorescent signals counted per chromosome in the newborn's cells. A doctor or genetic counsellor should always review the findings alongside clinical observations.
| Parameter | Normal | Abnormal (Trisomy) |
|---|---|---|
| Chromosome 13 signal count | 2 signals per cell | 3 signals per cell |
| Chromosome 21 signal count | 2 signals per cell | 3 signals per cell |
These ranges are general guidelines. Your doctor will interpret your results based on your child's age, health history, and other factors. Always consult a qualified healthcare professional for personalised medical advice.
Results During Special Conditions
Low-level mosaicism (where only a small proportion of cells carry the extra chromosome) may not be detected by this test. A normal result does not exclude all chromosomal abnormalities, as this test only screens for the two targeted chromosomes. Structural chromosomal changes, abnormalities of other chromosomes, and other genetic variants are outside the scope of this test. This is why it is often ordered alongside a chromosomal microarray or full chromosome analysis.
How to Maintain Healthy Levels
Chromosomal conditions are determined at conception and are not caused by diet or lifestyle. The following points are worth keeping in mind:
- Early identification through this FISH neonatal screen (2 probes Trisomy) test allows for timely specialist referrals and supportive care planning
- Genetic counselling can help families understand the results and make informed decisions about follow-up testing
- Mothers aged 35 and above have a higher statistical chance of having a baby with trisomy 21; genetic counselling before and during pregnancy may be beneficial for this group
Lupin Diagnostics FISH-Neonatal Screen (2 Probes Trisomy) Test Price and Home Collection
The FISH-Neonatal screen (2 probes Trisomy) test starts at ₹3,000 at Lupin Diagnostics, and home collection is available for peripheral blood samples.
| City | Approximate Price (₹) |
|---|---|
| Mumbai | 3000 |
| Pune | 3000 |
| Bangalore | 3000 |
| Chennai | 3000 |
Prices are indicative and may vary by location. Please confirm the current price at the time of booking.
How to Book
- Select the FISH-neonatal screen (2 probes Trisomy) test on the Lupin Diagnostics website.
- Choose your city and preferred time slot.
- Opt for home sample collection by a certified phlebotomist (for peripheral blood only), or visit your nearest Lupin Diagnostics centre.
- Receive your report via email or WhatsApp within 3 days.
Home Collection
Home collection is available across cities for peripheral blood samples collected in a sodium heparin tube. All samples are processed in NABL-accredited Lupin Diagnostics laboratories. Digital reports are accessible via email or WhatsApp once ready.
Frequently Asked Questions
The FISH-neonatal screen (2 probes Trisomy) test is a rapid genetic test that checks a newborn's cells for extra copies of chromosomes 13 and 21. It uses fluorescently labelled DNA probes to count chromosome signals in interphase cells. This helps detect trisomy conditions such as Down syndrome and Patau syndrome shortly after birth.
This test is ordered when a newborn shows physical signs that suggest a chromosomal disorder, such as low muscle tone, distinctive facial features, congenital heart defects, or extra fingers or toes. It is not a routine newborn screen and is used only when there is clinical suspicion of aneuploidy.
For home collection, a certified phlebotomist visits and collects around 3 mL of peripheral blood from the newborn into a green sodium heparin tube. The sample is labelled, stored at 2 to 8°C, and transported to the laboratory. All other sample types (bone marrow, cord blood, amniotic fluid, CVS) require hospital collection.
No. The FISH-neonatal screen (2 probes Trisomy) test only screens for the specific chromosomes targeted by its two probes. It does not detect structural chromosomal abnormalities, abnormalities of other chromosomes, or low-level mosaicism. A normal result should be reviewed alongside the clinical picture, and further testing may be needed.
An abnormal result, showing three signals for a targeted chromosome, indicates a trisomy for that chromosome. A genetic counsellor or paediatrician will explain the findings in detail and advise on further testing, such as full chromosome analysis or chromosomal microarray, to confirm the finding.
Results are typically available within 3 days of the laboratory receiving the sample. In urgent neonatal cases, turnaround may be faster. Your doctor will be notified once the report is ready, and you can also access it digitally through Lupin Diagnostics.
Yes. Clinical history is required for this test. The laboratory needs accurate details about the newborn's symptoms, birth observations, and family background to process and interpret the results correctly. Please bring all relevant documentation at the time of sample collection.
FISH-Neonatal Screen (2 Probes Trisomy) Test: Booking, Price, and Results
