MRCP2-2238

An 80-year-old woman is admitted to the hospital for a right hemicolectomy due to carcinoma of the caecum. She has a history of osteoarthritis and had a fibroma removed from her right breast two years ago. She is a non-smoker and drinks approximately 8 units of alcohol per week. Pre-operative investigations show a low Hb and MCV, but normal WCC and platelets. The procedure goes smoothly, but three days later she becomes jaundiced and complains of fatigue. postoperative investigations show a further drop in Hb and an increase in MCV, WCC, and platelets. What is the best investigation to confirm the diagnosis?