MRCP2-4589

A 56-year-old woman with a 3-year history of rheumatoid arthritis presents with joint pain and numbness in her hands. She is currently taking methotrexate 20 mg per week. The pain is worse in the mornings and she experiences intermittent paraesthesia that wakes her up at night. On examination, there is mild swelling and tenderness over the small joints of the hands and wrists, but no neurological deficits are noted. Her laboratory results show a low hemoglobin level, elevated white cell count, elevated platelets, and elevated ESR and CRP. What would be the most appropriate next step in her evaluation?