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Serum or plasma mass concentration of methotrexate (MTX)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of methotrexate, a medication used to treat certain cancers and autoimmune conditions, in your blood.

Quick summary

["Knowing your methotrexate levels helps doctors monitor your treatment effectiveness and manage side effects."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
14836-1
Short code
MTX SerPl-sCnc
Synonyms
MTX SerPl-sCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order this test if you’re taking methotrexate to check if the dose is working properly or if your body is handling the medication well. It’s also used to detect low levels of methotrexate in cases of overdose or poor absorption.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for a few hours before the blood draw if your test involves a fasting sample. Bring any medications or supplements you’re taking to your appointment.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but it usually doesn’t cause discomfort. The blood will be sent to a lab for testing.

What Does the Test Result Mean?

Results are interpreted based on your medical condition, dose of methotrexate, and how long it’s been since you took the medication. Your doctor will discuss the findings with you and explain any changes to your treatment plan.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Methotrexate Level

Frequently asked questions

How often should I get this test?
Your doctor will determine the frequency based on your treatment plan, how often you take methotrexate, and your overall health. It’s usually done at regular intervals, such as every few weeks or months, depending on your condition.
What are the possible side effects of methotrexate?
Common side effects include nausea, fatigue, mouth ulcers, or hair loss. Severe side effects, such as liver or kidney damage, are rare but require immediate attention. Let your doctor know if you experience any unusual symptoms.
Can I still take methotrexate if my levels are too high?
Yes, but your doctor will adjust your dose or treatment plan to lower the levels safely. They may also prescribe medications to protect your organs while you’re on methotrexate.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy