Karyotyping, Chorionic Villus (CVS)
About Karyotyping, Chorionic Villus (CVS)
| Field | Value |
|---|---|
| Also Known As | CVS Karyotyping, Chromosome Analysis CVS, Prenatal Karyotyping, Chorionic Villus Biopsy |
| Sample Type | Chorionic villus tissue (placental tissue) |
| Fasting Required | No |
| Report Time | 12 days |
| Recommended For | Pregnant women (10 to 13 weeks gestation) with high-risk screening results or a family history of genetic conditions |
| Price | Starting at ₹11,000 |
What is a Karyotyping, Chorionic Villus (CVS) Test?
The Karyotyping, Chorionic Villus (CVS) test is a prenatal diagnostic procedure that analyses the chromosomes of a developing foetus. A small sample of chorionic villus tissue, which is placental tissue that shares the same genetic material as the foetus, is collected and examined in a laboratory.
It is also known as the CVS karyotyping test or the prenatal karyotyping test. Doctors typically recommend this test between 10 and 13 weeks of pregnancy when there is a concern about chromosomal abnormalities.
What Does a Karyotyping, Chorionic Villus (CVS) Test Measure?
The CVS test analyses the chromosomes present in placental tissue to detect abnormalities in their number or structure. Here is what the test examines:
| Parameter | What It Reveals |
|---|---|
| Total chromosome count | Checks whether the foetus has the normal count of 46 chromosomes (23 pairs) |
| Chromosome number (female) | Normal female pattern is 46,XX |
| Chromosome number (male) | Normal male pattern is 46,XY |
| Chromosome structure | Identifies duplications, deletions, translocations, or inversions |
| Genetic abnormalities | Detects conditions such as Down syndrome, Edwards syndrome, and Turner syndrome |
Why is a Karyotyping, Chorionic Villus (CVS) Test Done?
Doctors recommend this test when there are specific risk factors or findings during early pregnancy that suggest a chromosomal problem.
Common Clinical Indications for This Test
Several clinical situations may prompt a doctor to recommend a CVS karyotyping test:
- Abnormal results from first-trimester screening (e.g., combined test or cell-free DNA screening)
- Increased nuchal translucency detected on ultrasound
- Structural abnormalities in the foetus seen on ultrasound
- Advanced maternal age (35 years or older at delivery)
- A previous pregnancy or child affected by a chromosomal condition
- A known family history of genetic disorders
Conditions This Test Can Help Detect
The Karyotyping, Chorionic Villus (CVS) test can help identify a range of chromosomal conditions, including:
- Down syndrome (trisomy 21, an extra chromosome 21)
- Edwards syndrome (trisomy 18, an extra chromosome 18)
- Patau syndrome (trisomy 13, an extra chromosome 13)
- Turner syndrome (monosomy X, a missing or incomplete X chromosome)
- Klinefelter syndrome (an extra X chromosome in males, 47,XXY)
- Chromosomal translocations, deletions, duplications, and inversions
Karyotyping, Chorionic Villus (CVS) During Pregnancy
The CVS test procedure is specifically designed for use during pregnancy, typically between 10 and 13 weeks of gestation. Unlike screening tests that estimate the probability of a chromosomal condition, this test provides a definitive diagnosis by directly examining foetal chromosomes. It is routinely offered to pregnant women who have abnormal screening results or known risk factors for foetal chromosomal abnormalities.
How to Prepare and What to Expect
Preparation for a CVS karyotyping test involves a few simple steps, along with important documentation to arrange before your appointment.
Do You Need to Fast?
No, fasting is not required before this test. You may eat and drink normally on the day of your appointment. However, your doctor may ask you to arrive with a full bladder, as this can help with ultrasound guidance during the procedure.
Practical Tips Before Your Test
Keep the following points in mind before attending your appointment:
- Bring a detailed clinical history, including your symptoms, previous test results, and family history, as this is required for the test
- Bring your completed PNDT Consent Form and Form G, as these documents are mandatory under Indian law and must be submitted before the procedure
- Inform your doctor about all medications you are currently taking, including blood thinners
- Attend a genetic counselling session before the procedure to understand the risks, benefits, and possible outcomes
- Arrange for a family member or friend to accompany you and take you home afterwards
- Avoid strenuous physical activity on the day of the procedure
Step-by-Step Procedure
The CVS test procedure involves collection of placental tissue by a specialist under ultrasound guidance. Here is what to expect:
- An ultrasound is performed first to confirm the gestational age and identify the exact location of the placenta
- The doctor will choose either a transabdominal (through the abdomen) or transcervical (through the cervix) approach, depending on the position of the placenta
- Under local anaesthetic, a needle or catheter is guided carefully to the placenta using continuous ultrasound monitoring
- A small sample of chorionic villus tissue (approximately 30 mg) is collected and immediately checked for adequacy before the procedure ends
- The sample is placed in a sterile container and stored under refrigeration (2 to 8°C) before dispatch to the laboratory
- After the procedure, you will be advised to rest for the remainder of the day and avoid strenuous activity for at least 48 hours
Factors That Can Affect Accuracy
Certain factors may influence the reliability of CVS karyotyping test results:
- Insufficient sample size or poor tissue quality
- Maternal cell contamination during sample collection
- Confined placental mosaicism (where the placenta and foetus carry different chromosomes)
- Failure of cells to grow during laboratory culture
- Gestational age at the time of sampling
Understanding Your Karyotyping, Chorionic Villus (CVS) Results
Results from a CVS test require careful interpretation by a qualified doctor or genetic counsellor alongside ultrasound findings and your medical history.
| Result | Typical Finding |
|---|---|
| Normal (negative) | 46 chromosomes present (46,XX or 46,XY) with no structural changes |
| Abnormal (aneuploidy) | Incorrect chromosome number, e.g., 47 chromosomes in Down syndrome |
| Structural abnormality | Deletions, duplications, translocations, or inversions identified |
These ranges are general guidelines. Your doctor will interpret your results based on your age, health history, and other factors. Always consult a qualified healthcare professional for personalised medical advice.
Results During Special Conditions
A few specific situations can affect how results are interpreted:
In approximately 1% to 2% of CVS cases, the placenta carries a chromosomal abnormality that is not present in the foetus. This is called confined placental mosaicism (CPM). When CPM is suspected, follow-up amniocentesis may be recommended to confirm the foetal karyotype.
Mosaicism, where two or more different cell lines are found in the same sample, occurs in approximately 2% of CVS results and may require further investigation. Prior or ongoing chemotherapy can cause chromosome breaks that interfere with karyotyping analysis. Always inform your doctor if this applies to you.
How to Support a Healthy Pregnancy
While chromosomal results cannot be altered, there are steps you can take to support a healthy pregnancy:
- Attend genetic counselling before and after the procedure to fully understand your results and next steps.
- Begin prenatal care early and keep up with regular ultrasound appointments to monitor foetal development.
- Share your personal and family history of genetic conditions with your doctor before and during pregnancy.
Lupin Diagnostics Karyotyping, Chorionic Villus (CVS) Price
The Karyotyping, Chorionic Villus (CVS) test at Lupin Diagnostics is priced starting at ₹11,000. This test requires a visit to a hospital where a medical specialist will safely extract the required tissue sample. Once collected by a clinical specialist, the tissue sample is securely transported to a Lupin Diagnostics centre for expert genetic checking and karyotype evaluation. City-wise prices are listed below.
| City | Approximate Price (₹) |
|---|---|
| BHOPAL | 11000 |
| CHENNAI | 11000 |
| HYDERABAD | 11000 |
| KOLKATA | 11000 |
| NAVI MUMBAI | 11000 |
| PUNE | 11000 |
Prices are indicative and may vary by location. Please confirm the current price at the time of booking.
How to Book
Follow these steps to book your CVS test at Lupin Diagnostics:
- Select the Karyotyping, Chorionic Villus (CVS) test on the Lupin Diagnostics website
- Choose your city and preferred centre location
- Visit the hospital at your scheduled time for tissue extraction by a medical specialist
- The hospital will securely transfer your sample to a Lupin Diagnostics laboratory for expert genetic analysis
- Receive your detailed report directly from Lupin Diagnostics via email or WhatsApp within 12 days
Frequently Asked Questions
Both tests examine foetal chromosomes, but they differ in timing and sample source. The CVS karyotyping test procedure is performed between 10 and 13 weeks using placental tissue, while amniocentesis is done after 15 weeks using amniotic fluid. CVS provides results earlier in pregnancy, which allows more time for decision-making.
A full karyotype, which examines all the foetal chromosomes under a microscope, typically takes up to 12 to 14 days. Rapid tests such as QF-PCR or FISH can provide targeted results for specific conditions like Down syndrome within approximately three working days.
No fasting is required before this test. You may eat and drink as normal. Your doctor may, however, ask you to have a full bladder on the day of the procedure to assist with ultrasound guidance.
You must bring a completed PNDT Consent Form and Form G, as these are legally required in India before the procedure can take place. A detailed clinical history, including previous test results and family history, is also required.
Doctors typically recommend this test for pregnant women with abnormal first-trimester screening results, increased nuchal translucency on ultrasound, advanced maternal age (35 or older), a previous child with a chromosomal condition, or a known family history of genetic disorders.
No. The Karyotyping, Chorionic Villus (CVS) test is designed to identify chromosomal abnormalities and may not detect conditions caused by mutations in a single gene. If a specific inherited condition is suspected, additional molecular or biochemical tests may be needed.
Confined placental mosaicism (CPM) occurs when the chromosomal pattern in the placenta differs from that of the foetus. This happens in approximately 1% to 2% of CVS cases. In such situations, a doctor may recommend a follow-up amniocentesis to confirm whether the foetus is actually affected.
Karyotyping, Chorionic Villus (CVS)
