Hematology Question 36

A 78 year old male is noted to have a haemoglobin of 89g/L with an MCV of 108fL. His neutrophil count is low at 0.9 x 10⁹/L and platelets are found to be 79,000. He feels tired and has no past medical history outside of hypertension, for which he is on hydrochlorothiazide.

Provide an approach for investigating his pancytopenia.