30th April 2024

A 70-year-old woman presents with a three-month history of increasing fatigue, bone pain, and unexplained weight loss.

A 70-year-old woman presents with a three-month history of increasing fatigue, bone pain, and unexplained weight loss. She has a past medical history of hypertension and type 2 diabetes. On examination, she has tenderness over her spine and ribs.

Investigations:

Haemoglobin: 95 g/L (120–160)

Serum Calcium: 3.0 mmol/L (2.2–2.6)

Serum Creatinine: 200 μmol/L (44–80)

Serum Protein Electrophoresis: Presence of monoclonal protein

Bone Marrow Aspirate: 40% plasma cells

Which of the following investigations is most important to further evaluate her bone disease?