30th April 2024

A 60-year-old woman presents with a 6-month history of increasing pain in her hand.

A 60-year-old woman presents with a 6-month history of increasing pain in her hand. She reports stiffness in her fingers that worsens with activity. On examination, there is bony swelling of the distal interphalangeal joints, and she experiences pain on palpation of these joints.

Investigations:

Haemoglobin: 140 g/L (120–160)

White cell count: 7.2 × 10⁹/L (4.0–11.0)

CRP: 8 mg/L (<5)

ESR: 20 mm/hr (0–20)

Which is the most appropriate first investigation?