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Serum or Plasma Methotrexate Concentration (Quantitative)

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

["Your methotrexate level helps doctors monitor your treatment dose and adjust it for safety and effectiveness."]

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

Key facts at a glance

LOINC
98991-3
Short code
MTX 5M p dose SerPl-sCnc
Synonyms
MTX 5M p dose 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 This Test Is Done

Your healthcare provider may order this test if you’re taking methotrexate to manage conditions like rheumatoid arthritis, psoriasis, or certain types of cancer. It helps ensure the medication is working properly and at a safe level in your body.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or vein to draw blood. It usually takes a few minutes. If you’re on a low-dose regimen, your provider may check levels more frequently.

What the Results Mean

Results are used to guide treatment adjustments. Too-high levels may cause side effects like nausea or kidney issues, while too-low levels might mean the medication isn’t working well. Your provider will discuss these findings with you.

Possible Side Effects

Methotrexate can cause mild side effects like nausea, fatigue, or mouth sores. Severe reactions (rare) may include liver damage or bone marrow suppression. Your provider will monitor you closely during treatment.

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 expect this test?
Your provider will determine the timing based on your treatment plan. For example, frequent monitoring may be needed if you’re taking high doses or have kidney issues.
Can I eat or drink before the blood draw?
You can eat and drink normally unless instructed otherwise. Avoid alcohol before the test, as it may affect test results.
What if my levels are too high or too low?
If levels are out of range, your provider may adjust your dose, switch medications, or recommend additional tests to protect your health.
  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