Which laboratory parameter is monitored regularly during methotrexate therapy to detect hepatotoxicity?

• A. Serum creatinine
• B. Urinalysis
• C. Liver function tests
• D. White blood cell count

Answer: (C)

Methotrexate can cause liver injury, so monitoring liver function tests is the way to detect hepatotoxicity. Regular LFTs track enzymes and other markers of liver health—ALT and AST signal hepatocellular injury, while bilirubin and alkaline phosphatase can indicate cholestasis or broader liver dysfunction. Baseline LFTs before starting methotrexate and periodic follow-ups during treatment help catch early liver injury, especially with risk factors such as higher cumulative doses, obesity, diabetes, alcohol use, or preexisting liver disease. Serum creatinine measures kidney function, urinalysis screens the urine, and white blood cell count monitors bone marrow suppression; none specifically track hepatotoxicity. So liver function tests are the appropriate parameter to monitor for this toxicity.