VNTR Chimerism Study [PRE-BMT] Test
About VNTR Chimerism Study [PRE-BMT] Test
| Field | Value |
|---|---|
| Also Known As | Pre-transplant chimerism assay, pre-BMT VNTR analysis, baseline chimerism study, chimerism DNA fingerprinting, engraftment baseline test |
| Sample Type | Peripheral blood (venous) in EDTA tube, from both recipient and donor |
| Fasting Required | No fasting required |
| Report Time | 5 days |
| Recommended For | Patients and donors scheduled for allogeneic bone marrow transplant or haematopoietic stem cell transplant; all ages and genders |
| Price | Starting at ₹12,000 |
What Is a VNTR Chimerism Study [PRE-BMT] Test?
The VNTR Chimerism Study [PRE-BMT] test is a specialised DNA-based blood test performed before a bone marrow transplant (BMT). It analyses specific regions of DNA in both the patient (recipient) and the donor to establish unique genetic profiles for each individual. Also known as a pre-transplant chimerism assay or engraftment baseline test, it creates the genetic reference point that all post-transplant monitoring depends on. The sample used is peripheral blood, collected into an EDTA tube.
What Does a VNTR Chimerism Study [PRE-BMT] Test Measure?
The VNTR Chimerism Study [PRE-BMT] test procedure examines specific DNA regions called VNTR (Variable Number of Tandem Repeats) loci. These are sections of DNA that vary in length among individuals, making them useful for telling one person's DNA apart from another's.
The test analyses the following elements:
| Component | What It Does |
|---|---|
| VNTR loci (e.g., D1S80, APO-B, D17S30, D1S111) | Identified by PCR amplification and gel electrophoresis to produce a DNA profile for each individual |
| Informative markers | Loci where recipient and donor show different alleles (genetic variants), selected for use in post-transplant monitoring |
| Recipient baseline profile | Confirms 100% recipient DNA before transplant |
| Donor baseline profile | Confirms 100% donor DNA before transplant |
The pre-BMT test does not measure chimerism directly. Instead, it identifies which genetic markers can reliably distinguish recipient from donor cells in future post-transplant samples.
Why Is a VNTR Chimerism Study [PRE-BMT] Test Done?
Doctors order this test as a required step before any allogeneic (donor-based) bone marrow or stem cell transplant. It is not triggered by symptoms but by the planned transplant itself. Below are the conditions and contexts that make this test necessary.
Common Symptoms That May Require This Test
Patients scheduled for BMT typically have conditions that cause blood cell abnormalities. The following are common reasons a BMT (and therefore this test) may be recommended:
- Extreme fatigue and weakness due to defective red blood cell production
- Frequent or severe infections from impaired immune function
- Unexplained bleeding or bruising caused by low platelet counts
- Persistent anaemia that does not respond to standard treatment
- Bone pain or swelling linked to abnormal bone marrow activity
- Recurrent fever without a clear infection source
- Pallor and breathlessness in children with inherited blood disorders
Conditions This Test Can Help Detect
The VNTR Chimerism Study [PRE-BMT] test is ordered for patients being treated for the following conditions:
- Leukaemia (blood cancer)
- Aplastic anaemia (bone marrow failure)
- Thalassaemia (an inherited condition causing abnormal haemoglobin)
- Lymphoma (cancer of the lymphatic system)
- Congenital immune deficiency diseases
VNTR Chimerism Study [PRE-BMT] Test for Chronic Disease Monitoring
This pre-BMT test is the essential first step in a long-term monitoring process. After the transplant, doctors use regular chimerism tests to assess whether the donor's cells have successfully established themselves and whether the disease has returned. Most transplant programmes monitor chimerism at 30, 90, and 180 days post-transplant, and annually thereafter. The baseline established by this pre-BMT test makes all of that ongoing tracking possible.
How to Prepare and What to Expect
No complex preparation is needed for this test, but a few practical steps will help ensure the sample is collected correctly and on time.
Do You Need to Fast?
No. Fasting is not required for the VNTR Chimerism Study [PRE-BMT] test. You may eat and drink normally before the blood draw.
Practical Tips Before Your Test
Keep the following points in mind before your appointment:
- The sample must be collected before conditioning therapy (preparatory chemotherapy or radiotherapy) begins, so coordinate timing carefully with your transplant team.
- Both the recipient's and the donor's blood samples are required, ideally collected around two weeks before the scheduled transplant.
- Inform your doctor about any recent blood transfusions, as these may interfere with DNA analysis.
- Ensure that both samples are labelled clearly and correctly to avoid any mix-up between the recipient and the donor.
- Bring a detailed clinical history, including your diagnosis, previous test results, and transplant plan, as this is required for the test.
Step-by-Step Procedure
Here is what to expect during sample collection for both the recipient and the donor:
- A trained phlebotomist (blood collection specialist) confirms your identity and the purpose of the sample before beginning.
- The venepuncture site, usually the inner arm, is cleaned and prepared.
- A small 2 mL blood sample is drawn into a lavender-top EDTA tube (a tube containing anticoagulant to preserve the sample).
- This process is repeated separately for the donor, with each sample clearly labelled.
- Both samples are stored at refrigeration temperature (2 to 8 degrees Celsius) and transported to the laboratory.
- In the lab, DNA is extracted from each sample, and VNTR markers are amplified using End Point PCR to establish individual genetic profiles.
Factors That Can Affect Accuracy
The following factors can affect the reliability of results:
- Incorrect or swapped labelling of recipient and donor samples
- Poor sample quality or inadequate anticoagulation
- Recent blood transfusions prior to sample collection
- Delay in transporting the sample beyond the acceptable window
- Insufficient DNA concentration in the collected sample
Understanding Your VNTR Chimerism Study [PRE-BMT] Test Results
Your pre-BMT results establish a genetic baseline and are reviewed by your transplant team alongside post-transplant chimerism data. The table below explains the key terms used in chimerism reporting (relevant primarily for post-transplant comparisons made against this baseline).
| Chimerism Status | Definition |
|---|---|
| Complete donor chimerism | More than 95% of cells in the sample are from the donor; indicates successful engraftment |
| Mixed chimerism | Between 5% and 95% donor cells present; may indicate partial engraftment or early signs of rejection |
| Absent donor chimerism | Less than 5% donor cells detected; indicates graft failure or relapse |
| Split chimerism | Different proportions of donor cells found in different cell types (e.g., blood-forming vs immune cells) |
For the pre-BMT test specifically, the patient's sample will show 100% recipient DNA, and the donor's sample will show 100% donor DNA. This is the expected and normal baseline result.
Disclaimer: 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.
How to Maintain Healthy Levels
While chimerism is managed by your transplant team, the following general steps support a better transplant outcome:
- Attend all scheduled post-transplant chimerism monitoring appointments as advised by your doctor.
- Follow your immunosuppression medication plan precisely to help the donor cells establish themselves.
- Report any new or unusual symptoms (such as persistent fever, fatigue, or bleeding) to your doctor promptly.
Lupin Diagnostics VNTR Chimerism Study [PRE-BMT] Test Price and Home Collection
The VNTR Chimerism Study [PRE-BMT] test cost at Lupin Diagnostics starts at ₹7,200, and home sample collection is available for both the recipient and donor.
| City | Approximate Price (₹) |
|---|---|
| Mumbai | 12000 |
| Pune | 12000 |
| Bangalore | 12000 |
| Chennai | 12000 |
Disclaimer: 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 the VNTR Chimerism Study [PRE-BMT] test online:
- Select the test on the Lupin Diagnostics website.
- Choose your city and preferred time slot.
- Opt for home sample collection by a certified phlebotomist, or visit your nearest Lupin Diagnostics centre.
- Receive your report via email or WhatsApp within the stipulated turnaround time.
Home Collection
VNTR Chimerism Study [PRE-BMT] test home collection is available across cities, allowing both the recipient and donor to have their blood drawn at home by a certified phlebotomist. All samples are processed in NABL-accredited laboratories to ensure accuracy and reliability. Digital reports are accessible via email or WhatsApp once ready.
Frequently Asked Questions
VNTR (Variable Number of Tandem Repeats) markers are inherited DNA sequences that differ among individuals. Before a transplant, this test maps the unique genetic profiles of both the patient and the donor. This baseline is essential so that after the transplant, doctors can measure how much of the patient's blood-forming system has been replaced by donor cells.
The test compares the DNA of the recipient and the donor side by side. Without a sample from both individuals, it is not possible to identify which genetic markers are unique to each person. These distinctive markers are then used in post-transplant tests to calculate the proportion of donor versus recipient cells.
No fasting or dietary changes are needed. However, the sample must be collected before conditioning therapy begins. You should also inform your doctor about any recent blood transfusions, as these can affect DNA analysis. Bringing a complete clinical history to the appointment is also required.
Swapped or incorrectly labelled samples would produce an unreliable baseline, which could affect all subsequent post-transplant monitoring. This is why correct labelling at the time of collection is critical. Always ensure a trained phlebotomist handles the collection and labelling of both samples.
Leukaemia, aplastic anaemia, thalassaemia, lymphoma, and congenital immune deficiency diseases are among the most common conditions treated with allogeneic bone marrow or stem cell transplantation. The VNTR Chimerism Study [PRE-BMT] test is a standard requirement for all patients undergoing this type of transplant.
The pre-BMT test itself only establishes a baseline. It is the post-transplant chimerism tests, compared against this baseline, that can detect early signs of relapse or graft failure. Regular monitoring after the transplant is essential for timely clinical decisions.
VNTR Chimerism Study [PRE-BMT] Test
