30th April 2024

A 57-year-old man, known to have hypertension, presents with a 6-month history of increasing tiredness and a feeling of fullness in his abdomen.

A 57-year-old man, known to have hypertension, presents with a 6-month history of increasing tiredness and a feeling of fullness in his abdomen. He reports no significant weight loss, night sweats, or fever. His blood pressure is 138/85 mmHg. On examination, he has mild splenomegaly.

Investigations:

Haemoglobin: 180 g/L (130-170)

White cell count: 12 × 10⁹/L (4.0-11.0)

Platelets: 450 × 10⁹/L (150-400)

Mean corpuscular volume (MCV): 86 fL (80-96)

Lactate dehydrogenase: 250 IU/L (70-250)

Uric acid: 0.35 mmol/L (0.20-0.42)

Which investigation is most appropriate to establish the diagnosis?