Warfarin Therapeutic Response Predictive Assay (VKORC1 & CYP2C9) Test: Booking, Price, and Results
About Warfarin Therapeutic Response Predictive Assay (VKORC1 & CYP2C9) Test: Booking, Price, and Results
| Field | Value |
|---|---|
| Also Known As | Warfarin Sensitivity Test, Warfarin Pharmacogenetic Test, CYP2C9/VKORC1 Genotyping, Warfarin Response Genotype, Coumadin Genotype Test |
| Sample Type | Peripheral blood (EDTA tube) |
| Fasting Required | No fasting required |
| Report Time | 5 days |
| Recommended For | Adults of any gender who are starting warfarin therapy or have difficulty maintaining a stable INR |
| Price | Starting at ₹7,800 |
What Is a Warfarin Therapeutic Response Predictive Assay (VKORC1 & CYP2C9) Test?
The Warfarin Therapeutic Response Predictive Assay (VKORC1 & CYP2C9) test is a pharmacogenetic test that examines specific gene variants to predict how a person will respond to warfarin, a commonly prescribed anticoagulant (blood-thinning) medicine. By analysing DNA from a small blood sample, the test helps doctors identify the right starting dose of warfarin for each individual. It is also known as the Warfarin Sensitivity Test or CYP2C9/VKORC1 Genotyping.
What Does a Warfarin Therapeutic Response Predictive Assay (VKORC1 & CYP2C9) Test Measure?
This test analyses two key genes that directly influence how the body processes and responds to warfarin. The findings from both genes are considered together to guide dosing decisions.
| Gene and Variant | What It Does |
|---|---|
| VKORC1 (-1639 G>A variant) | Encodes an enzyme involved in the vitamin K cycle. This enzyme is the direct target of warfarin. Certain variants reduce its activity, making a person more sensitive to the drug. |
| CYP2C9 (*2 variant) | Encodes an enzyme that breaks down the active form of warfarin. The *2 variant reduces this enzyme's activity by around 30%, causing warfarin to stay in the body longer. |
| CYP2C9 (*3 variant) | A more significant variant that reduces the enzyme's activity by around 90%, leading to considerably higher warfarin levels in the blood if standard doses are used. |
Why Is a Warfarin Therapeutic Response Predictive Assay (VKORC1 & CYP2C9) Test Done?
Warfarin dosing is notoriously difficult to get right. Genetic variation explains a large part of why two people on the same dose can have very different responses. This test helps personalise dosing before problems arise.
Common Symptoms That May Require This Test
The test is not ordered for symptoms in the usual sense. Instead, it is indicated in specific clinical situations. The following are the most common reasons a doctor may prescribe it:
- Starting warfarin therapy for the first time
- Difficulty maintaining INR (International Normalised Ratio) within the target range
- Unexplained bleeding episodes while on warfarin
- Blood clots occurring despite being on warfarin
- A personal or family history of abnormal responses to warfarin
- Requiring multiple dose changes to stabilise INR
- Need to stop warfarin before surgery and estimate how long it will take to clear
Conditions This Test Can Help Detect
This test does not diagnose conditions directly. It identifies genetic variants that help guide warfarin therapy for the following situations:
- Atrial fibrillation (an irregular heartbeat requiring anticoagulation)
- Deep vein thrombosis or pulmonary embolism (blood clots in veins or lungs)
- Prevention of thrombosis due to inherited or acquired clotting disorders
- Patients recovering from hip replacement surgery who need anticoagulation
How to Prepare and What to Expect
No special preparation is needed for the Warfarin Therapeutic Response Predictive Assay (VKORC1 & CYP2C9) test. The steps below describe what typically happens at collection.
Do You Need to Fast?
No, fasting is not required. This test analyses your DNA, which is not affected by food or drink. You may eat and drink normally before the test.
Practical Tips Before Your Test
A few simple steps help ensure a smooth collection and accurate result.
- Bring a detailed clinical history, including your symptoms, previous test results, and current medications, as this is required for the test.
- Drink adequate water before your appointment to make the blood draw easier.
- Wear a short-sleeved or loose-sleeved top for easy access to the arm.
- Inform your doctor about all medicines you are currently taking, including over-the-counter drugs and supplements.
- No dietary restrictions apply before this test.
Step-by-Step Procedure
Here is what to expect during blood collection for this test:
- A trained phlebotomist will clean a small area on your inner arm with an antiseptic wipe.
- A thin needle is inserted into a vein, and approximately 2 mL of blood is collected into a lavender-coloured EDTA tube.
- The needle is removed, and gentle pressure is applied to the puncture site to stop any minor bleeding.
- The labelled sample is stored at a refrigerated temperature (2 to 8°C) to maintain quality during transit.
- The sample is sent to an NABL-accredited Lupin Diagnostics laboratory for DNA extraction and analysis using End Point PCR and RFLP (Restriction Fragment Length Polymorphism).
- Results are prepared and delivered within 5 days.
Factors That Can Affect Accuracy
Certain factors may influence the quality or interpretation of results.
- Use of incorrect sample containers (plasma or serum samples, or heparin-based tubes, are not acceptable for this test)
- Poor sample storage or delayed transport
- Rare genetic sequence variations that the test may not detect
- Non-genetic factors, such as age, weight, diet, liver function, kidney function, and other medicines, can also affect warfarin response, independently of these gene variants
Understanding Your Warfarin Therapeutic Response Predictive Assay (VKORC1 & CYP2C9) Test Results
Results from this test are reported as genotypes rather than numerical values. A doctor will use this information alongside clinical details to guide warfarin dosing. The table below outlines what different genotype combinations typically mean.
| Genotype | Warfarin Sensitivity | Expected Dose Adjustment |
|---|---|---|
| CYP2C9 *1/*1 (normal) | Normal metaboliser | Standard dosing |
| CYP2C9 *1/*2 | Intermediate metaboliser | Approximately 19% dose reduction per allele |
| CYP2C9 *1/*3 | Intermediate metaboliser | Approximately 33% dose reduction per allele |
| CYP2C9 *2/*2, *2/*3, or *3/*3 | Poor metaboliser | Significant dose reduction required |
| VKORC1 GG | Low sensitivity | Higher doses typically needed |
| VKORC1 GA | Intermediate sensitivity | Moderate dose adjustment |
| VKORC1 AA | High sensitivity | Approximately 28% dose reduction per A allele |
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.
Results During Special Conditions
Some factors outside of genetics can also alter how a patient responds to warfarin.
- Around half of the variation in warfarin dosing requirements is linked to non-genetic factors such as age, body weight, smoking status, existing health conditions, and other medicines taken alongside warfarin.
- Liver disease and kidney disease can affect how the body processes warfarin, independent of these genetic variants.
- Vitamin K intake from green leafy vegetables can influence warfarin's effectiveness, so consistent dietary habits are important.
- There are differences in the distribution of VKORC1 and CYP2C9 genotypes across ethnic populations, including notable variation among Indian patients compared to other populations.
How to Maintain Healthy Levels
These are general wellness tips to support safe warfarin therapy based on your genetic results:
- Keep your vitamin K intake consistent day to day. Sudden increases or decreases in green leafy vegetables (such as spinach or fenugreek) can affect your INR.
- Attend all scheduled INR monitoring appointments, as genetic testing guides initial dosing but does not replace ongoing blood monitoring.
- Share your full medication list with your doctor regularly, as many common medicines interact with warfarin.
Lupin Diagnostics Warfarin Therapeutic Response Predictive Assay (VKORC1 & CYP2C9) Test Price and Home Collection
The Warfarin Therapeutic Response Predictive Assay (VKORC1 & CYP2C9) test cost starts at ₹7,800 at Lupin Diagnostics, and home collection is available for this test. The city-wise pricing details are listed below.
| City | Approximate Price (₹) |
|---|---|
| Mumbai | 7800 |
| Pune | 7800 |
| Bangalore | 7800 |
| Chennai | 7800 |
Disclaimer: Prices are indicative and may vary by location. Please confirm the current price at the time of booking.
How to Book
Booking your Warfarin Therapeutic Response Predictive Assay (VKORC1 & CYP2C9) test online is straightforward.
- 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 5 days.
Home Collection
Lupin Diagnostics offers Warfarin Therapeutic Response Predictive Assay (VKORC1 & CYP2C9) test home collection across multiple cities in India. A certified phlebotomist visits your home at a time that suits you, collecting the blood sample in a properly labelled EDTA tube. All samples are processed in NABL-accredited laboratories, and your digital report is shared securely once ready.
Frequently Asked Questions
This is a genetic test that examines two specific genes, VKORC1 and CYP2C9, to predict how your body will respond to warfarin. The results help your doctor choose a starting dose that is safer and more appropriate for you, based on your individual genetic profile.
The test is generally recommended for people who are about to start warfarin therapy, those who have had trouble maintaining a stable INR, and patients with a personal or family history of abnormal responses to warfarin. It may also be useful before surgery to estimate how long warfarin will take to clear from the body.
Your genetic makeup does not change over time, so this is typically a once-in-a-lifetime test. However, regular INR blood tests remain essential throughout the duration of warfarin therapy, as genetics is only one part of what determines your response to the medicine.
No fasting is required. This test analyses your DNA from a blood sample, and DNA is not affected by eating or drinking. You can have your normal meals and drinks before the test.
No. Genetic testing helps guide the initial dose of warfarin, but it does not replace INR monitoring. INR tests need to be done regularly throughout your warfarin therapy to ensure your blood is clotting within the safe target range.
No. This test is specific to warfarin. Newer anticoagulants such as rivaroxaban and dabigatran work through different mechanisms and are not metabolised via the CYP2C9 pathway, so these genetic variants do not apply to them.
Warfarin Therapeutic Response Predictive Assay (VKORC1 & CYP2C9) Test: Booking, Price, and Results
