TPMT Enzyme Activity Thiopurine Methyl Transferase Plasma Test

What Does the TPMT Test Measure?

The TPMT Test measures how efficiently your body can process thiopurine medications by assessing enzyme activity in red blood cells.

It helps doctors to:

• Assess Thiopurine Drug Metabolism: Determines whether your body can safely break down medications like azathioprine or mercaptopurine.
• Prevent Toxic Side Effects: Identifies individuals at risk of drug-induced bone marrow suppression.
• Guide Drug Dosing: Supports safe and personalised medication adjustment.
• Optimise Treatment: Enables precision dosing for autoimmune, oncological, and transplant patients.
• Support Pharmacogenetic Testing: Provides insights into individual genetic differences in drug metabolism.

Who Should Get a TPMT Test and When Is It Needed?

Indications for a TPMT Test

Your doctor may recommend a TPMT Test if you are:

• About to start therapy with thiopurine medications such as azathioprine, mercaptopurine, or thioguanine.
• Receiving treatment for autoimmune diseases like Crohn’s disease, ulcerative colitis, lupus, or rheumatoid arthritis.
• Undergoing chemotherapy or immunosuppressive therapy.
• A transplant recipient requiring long-term thiopurine therapy.

Who Should Get a TPMT Test?

• About to start therapy with thiopurine medications such as azathioprine, mercaptopurine, or thioguanine.
• Receiving treatment for autoimmune diseases like Crohn’s disease, ulcerative colitis, lupus, or rheumatoid arthritis.
• Undergoing chemotherapy or immunosuppressive therapy.
• A transplant recipient requiring long-term thiopurine therapy.

Why Is a TPMT Test Done?

The TPMT Test plays a vital role in preventing drug toxicity and ensuring the safe use of thiopurine drugs. By measuring enzyme activity before treatment, doctors can avoid potentially life-threatening side effects and individualise dosing.

Approximately 89 percent of people have normal TPMT activity, 11 percent have reduced activity, and less than 1 percent have little or no detectable activity. Testing before starting therapy helps determine which group you fall into, allowing for safe and effective treatment decisions.

TPMT Test Booking & Reports – Metropolis Healthcare

How to Book a TPMT Test and Access Your Reports

1. Book Your Test Easily
   You can book your TPMT Test online through the Metropolis Healthcare website or mobile app, or by visiting your nearest Metropolis Lab.
2. Sample Collection
   A healthcare professional draws 3 ml of blood into an EDTA vacutainer from a vein in your arm.
3. Laboratory Processing
   The sample is tested at a NABL & CAP accredited Metropolis Lab using Enzyme Immunoassay (EIA) to measure TPMT enzyme activity.
4. Report Access
   Your report will be available digitally via email, WhatsApp, or the Metropolis Healthcare website and app.

Is Home Sample Collection for TPMT Test Available Near You?

Yes, Metropolis Healthcare offers home sample collection for the TPMT Test.

Our trained phlebotomists ensure sterile, safe, and comfortable blood collection at your convenience.

How Long Does It Take to Get the TPMT Test Report?

Reports are generally available on the same day once the sample reaches the Metropolis Lab.
Note: Reporting time and cost may vary based on your location.

Where Can You View or Collect Your TPMT Test Results?

You can access your reports conveniently through:

1. The Metropolis Healthcare website or app.
2. Direct email or WhatsApp delivery.
3. Printed report collection from your nearest Metropolis Lab.

How Is a TPMT Test Done? (Step-by-Step Procedure)

The TPMT Test is performed through a simple blood collection process:

• Preparation: A tourniquet is applied to your upper arm to make veins visible.
• Cleaning: The puncture site is cleaned using antiseptic.
• Sample Collection: About 3 ml of blood is drawn into an EDTA vacutainer.
• Completion: The needle is removed and a small bandage applied.
• Processing: The sample is analysed using Enzyme Immunoassay (EIA) to measure TPMT enzyme activity.

Conditions That May Affect TPMT Test Accuracy

Certain factors can affect the accuracy of TPMT test results:

• Current use of thiopurine medications: Can influence enzyme activity readings.
• Recent blood transfusion: May temporarily alter enzyme levels.
• Severe illness or infection: Can affect red blood cell enzyme activity.
• Incomplete clinical information: May impact interpretation of results.

Diseases Detected or Ruled Out by the TPMT Test

• Thiopurine-induced myelosuppression
• Cytopenia or bone marrow suppression
• Drug toxicity in autoimmune, cancer, or transplant patients
• Genetic enzyme deficiency syndromes

TPMT Test Price in Different Cities

The cost of a TPMT Test may vary depending on your location. Here's a table showing the approximate price range for the TPMT Test at Metropolis Healthcare in major Indian cities:

The TPMT Test cost may vary depending on the city and the specific tests included in the panel. However, Metropolis Healthcare offers competitive TPMT Test prices across major cities in India.

References

1. Relling M.V., et al. (2019). CPIC guidelines for thiopurine methyltransferase (TPMT) genotype and thiopurine dosing. Clinical Pharmacology & Therapeutics, 105(5), 1095–1105. PMID: 30561839
2. Weinshilboum R.M., et al. (2010). Thiopurine pharmacogenetics: clinical and molecular studies of TPMT. Drug Metabolism and Disposition, 38(3), 377–387. PMID: 20031229
3. Lennard L. (2014). TPMT in the treatment of Crohn’s disease and acute lymphoblastic leukaemia. British Journal of Clinical Pharmacology, 78(4), 703–714. PMID: 24597782
4. Colombel J.F., et al. (2016). Effect of TPMT activity on adverse events and efficacy in thiopurine therapy. Gut, 65(8), 1391–1399. PMID: 26283809
5. Hindorf U., et al. (2020). Thiopurine therapy and pharmacogenetics: a review. Therapeutic Advances in Gastroenterology, 13, 1756284820974914. PMID: 33343382