MSRA-0971

MSRA-0971

A 68-year-old woman presents to her General Practitioner with worsening back pain over a period of several months. She also feels generally unwell. She is exhausted, has a dry mouth and is constipated.
Investigations:
Investigation Result Normal value
Haemoglobin (Hb) 93 g/l 115–155 g/l
White cell count (WCC) 6.4 × 109/l 4.0–11.0 × 109/l
Platelets (PLT) 380 × 109/l 150–400 × 109/l
Mean corpuscular volume (MCV) 100 fl 80–100 fl
Erythrocyte sedimentation rate (ESR) 94 mm/h < 15 mm/h
Estimated glomerular filtration rate (eGFR) 32 ml/min per 1.73 m2 > 90 ml/min per 1.73 m2
Corrected calcium (Ca2+) 2.8 mmol/l 2.2–2.6 mmol/l
What is the most appropriate initial investigation to confirm the diagnosis in this patient?