Blood tests on methotrexate
For people taking low-dose methotrexate for rheumatoid arthritis, psoriasis, psoriatic arthritis or a similar condition.
11 tests explainedAI-verified against cited sources. Awaiting expert reviewLast reviewed 2026-10-19
Methotrexate is the preferred first long-term medicine for rheumatoid arthritis in U.S. guidelines, and it is also used for psoriasis and other conditions. Because it can affect blood counts, the liver and the kidneys, regular blood tests are part of taking it. Checks are frequent at the start and after a dose change, then settle into a steady rhythm.
The tests that matter most
Most important first. Each one links to its full page, where the note for this group sits near the top.
Alanine Aminotransferase (ALT)
Methotrexate can affect the liver, so liver enzymes are checked before starting and regularly after. The British Society for Rheumatology (BSR) suggests ALT, AST or both at every routine check.
Sources: British Society for Rheumatology (2017) and U.S. National Library of Medicine (2026)
- Men, 18+
- 0–44 U/L
- Women, 18+
- 0–32 U/L
White Blood Cell Count
Methotrexate can lower the blood cells made in the bone marrow. White cells, which fight infection, are counted at every routine check, and the BSR says a gradual fall is worth noticing as well as a single low result.
Sources: British Society for Rheumatology (2017) and U.S. National Library of Medicine (2026)
- Usual adult range
- 3.8–10.8 ×10³/µL
Neutrophils (Absolute)
Neutrophils are the white cells that respond first to bacteria. The BSR lists a low neutrophil count among the results that should prompt an urgent call to the rheumatology team.
- Usual adult range
- 1.4–7 ×10³/µL
Platelet Count
Platelets help blood clot, and methotrexate can lower them along with other blood cells. They are part of the full blood count the BSR suggests at every check.
Sources: British Society for Rheumatology (2017) and U.S. National Library of Medicine (2026)
- Usual adult range
- 150–450 ×10³/µL
Hemoglobin
Hemoglobin is the red cell part of the blood count. The label warns that methotrexate can lower all the blood cell lines, so hemoglobin is read with white cells and platelets.
Sources: U.S. National Library of Medicine (2026) and British Society for Rheumatology (2017)
- Men, 16+
- 13–17.7 g/dL
- Women, 16+
- 11.1–15.9 g/dL
Mean Corpuscular Volume (MCV)
MCV is the average size of red blood cells. The BSR lists a raised MCV among the results that should prompt a call to the rheumatology team.
- Usual adult range
- 80–100 fL
Eosinophils (Absolute)
Eosinophils are white cells often linked to allergies, and they are counted as part of the full blood count. The BSR lists an unexplained rise in eosinophils among the results that should prompt an urgent call to the rheumatology team.
- Usual adult range
- 0–0.5 ×10³/µL
Creatinine
When the kidneys work less well, methotrexate is cleared more slowly and side effects become more likely. That is why creatinine is checked before starting and at every routine check.
Sources: U.S. National Library of Medicine (2026) and British Society for Rheumatology (2017)
- Men, 15+
- 0.74–1.35 mg/dL
- Women, 16+
- 0.59–1.04 mg/dL
eGFR (Creatinine-based)
eGFR is worked out from creatinine and checked with it. The BSR lists a low eGFR, or a large rise in creatinine over 12 months, among the results to act on.
- Usual adult range
- 60 and above mL/min/1.73 m²
Albumin
Albumin is part of the BSR's routine methotrexate checks. An unexplained fall in albumin is one of the results it asks clinics to follow up.
- Usual adult range
- 3.5–5 g/dL
Aspartate Aminotransferase (AST)
AST is a liver enzyme often checked with ALT. The BSR accepts ALT, AST or both as the liver test, so which one appears on a report depends on the clinic.
- Men, 14+
- 8–48 U/L
- Women, 14+
- 8–43 U/L
Ranges shown are the usual adult ranges labs print. The range on your own report is the one your result is judged against.
Getting results you can compare
- When starting methotrexate, the BSR suggests blood tests every 2 weeks until the dose has been stable for 6 weeks, then monthly for 3 months, then at least every 12 weeks. After a dose increase, it suggests tests every 2 weeks until the new dose has been stable for 6 weeks, then a return to the earlier schedule.
- Each routine check in the BSR guideline covers the same set: full blood count, creatinine or eGFR, ALT, AST or both, and albumin.
Good to know
- Trends matter as well as single results. The BSR gives slow falls in white cells or albumin, and rising liver enzymes, as examples worth noticing.
- For people with rheumatoid arthritis and fatty liver disease who take methotrexate, the American College of Rheumatology's 2021 guideline suggests more frequent monitoring, every 4 to 8 weeks.
- The U.S. label doesn't set a fixed schedule for arthritis or psoriasis. It asks for blood counts, liver tests and kidney tests at the start, from time to time during treatment, and as needed. Guidelines such as the BSR's fill in the timing.
Sources: U.S. National Library of Medicine (2026) and British Society for Rheumatology (2017)
Questions you could ask
- How often will I need blood tests now, and will that change later?
- Which results would you want to hear about between visits?
- Are any of my results drifting, even if they're still in range?
- Does my liver health change how often we should check?
Sources
- BSR and BHPR guideline for the prescription and monitoring of non-biologic disease-modifying anti-rheumatic drugs, British Society for Rheumatology (2017)
- 2021 American College of Rheumatology Guideline for the Treatment of Rheumatoid Arthritis, American College of Rheumatology (2021)
- Trexall (methotrexate) tablets: prescribing information, U.S. National Library of Medicine (2026)
AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-19. How we build and check these pages.
Educational information, not medical advice. Blood Test Tracker doesn’t diagnose or treat, and it doesn’t replace your clinician. Talk with your clinician before changing medications, supplements or care.