Pre-Treatment Testing Requirements for Methotrexate

Essential Baseline Laboratory Tests

The American Academy of Dermatology recommends obtaining complete blood count with differential, liver function tests, serum creatinine, and hepatitis B and C serologic studies before initiating methotrexate therapy 1, 2, 3, 4
Complete blood count (CBC) with differential and platelet count is required prior to starting methotrexate to assess the risk of myelosuppression 1, 2, 3
Serum creatinine measurement is mandatory before initiation to assess renal function, as methotrexate is eliminated almost entirely by the kidneys 1, 2, 3, 4
Liver function tests including ALT, AST, alkaline phosphatase, albumin, and bilirubin must be obtained to monitor hepatotoxicity 1, 2, 3, 4
Hepatitis B and C antibody testing is recommended for all patients prior to initiating methotrexate to assess the risk of hepatotoxicity 1, 2, 3, 4

Non-invasive baseline liver fibrosis assessment is recommended before starting methotrexate in psoriasis patients 5, 6
Baseline liver biopsy is NOT recommended regardless of risk factors 5, 6

Patients should limit alcohol intake to well below national guidelines 7
Medication history should be obtained to identify potential drug interactions including NSAIDs, salicylates, sulfonamides, trimethoprim, and probenecid 4
Reproductive planning is essential, and women must use two methods of contraception and have a pregnancy test prior to starting therapy 7
Family history of inheritable liver disease should be obtained 5, 6

A test dose of 2.5-5 mg should be considered, especially in patients with impaired kidney function 4, 5, 6

Hepatitis B and C screening should not be skipped even in patients without obvious risk factors 1, 2, 3, 4
Serum creatinine should not be relied upon solely in elderly patients or those with low muscle mass - calculate GFR to accurately assess renal function 4
Routine baseline liver biopsies should not be performed in psoriasis patients 5, 6
Pregnancy testing should be performed in women of childbearing potential before initiating therapy 7