What is the Methotrexate test?

The Methotrexate test measures the concentration of methotrexate in the bloodstream. Methotrexate is a medication used in autoimmune conditions, inflammatory diseases, and certain cancers, where precise dosing is essential for safety.

Because methotrexate can affect the bone marrow, liver, kidneys, and immune system, monitoring blood levels helps ensure the drug is being cleared appropriately and is not accumulating to harmful levels. This test is part of therapeutic drug monitoring (TDM) in selected clinical settings.

Why do I need a Methotrexate test?

Monitoring methotrexate levels is important to balance treatment effectiveness with safety, especially during ongoing or high-dose therapy.

You may need this test if you:

• Are receiving methotrexate treatment

• Require monitoring during dose adjustment

• Have reduced kidney function

• Experience side effects such as nausea or mouth ulcers

• Are on long-term methotrexate therapy

• Are receiving high-dose methotrexate in hospital care

• Need assessment of drug clearance

Providing dosing time and clinical details improves interpretation.

Benefits of the test

1. Supports safe methotrexate use
   Helps prevent drug accumulation and toxicity.

2. Guides dose adjustment
   Supports personalised treatment decisions.

3. Important in high-dose therapy
   Essential in oncology and specialist care.

4. Monitors drug clearance
   Especially important in kidney impairment.

5. Reduces risk of adverse effects
   Enables early detection of unsafe levels.

6. Simple blood-based testing
   Requires only one blood sample.

7. Widely used in specialist practice
   Standard in methotrexate monitoring pathways.

8. Improves treatment safety
   Supports proactive clinical decision-making.

Step-by-step: How we offer testing

Clinic-based testing (UK-wide)

• Choose your nearest UK clinic

• Attend your appointment

• Blood sample taken at the appropriate time relative to dosing

• Clinical details recorded

• Sample sent to the laboratory

Home or hotel visit (+£60, UK-wide)

• Mobile phlebotomist arranged where appropriate

• Blood sample taken with correct timing

• Sample securely transported to the laboratory

Your results explained

Low / undetectable level

• Methotrexate not detected or very low

• Expected in low-dose weekly therapy

• Suggests appropriate clearance

Therapeutic level

• Methotrexate within expected range

• Target levels depend on dose and indication

• Suggests effective and safe exposure

High level

• Methotrexate above expected range

• Indicates delayed clearance

• Increased risk of toxicity, particularly to kidneys and bone marrow

Target ranges vary significantly depending on dose, timing, and clinical indication.