AKT-5556

AKT-5556

An 80-year-old gentleman presents to you with a complaint of a change in bowel habit. He reports that over the last 1-2 months he has gone from having firm stools passed once a day to looser stools passed 3-4 times a day. He has noticed some vague lower abdominal pains and has lost 2-3 kilograms in weight, he denies any blood loss per rectum or black stools. He says he otherwise feels OK. He was seen about 2 weeks ago by a colleague who sent a stool sample to the lab and ordered some initial investigations.

On examination, you note pale conjunctiva and angular stomatitis, you cannot elicit any focal abdominal signs and rectal examination is normal.

The stool sample was negative and the bloods have revealed a haemoglobin of 94 g/L (normal range 125-165). Thyroid function, renal function, liver function and coeliac screen are all normal. ESR is 68 (normal <20). You are expecting the ferritin to be low, but it returns as 568 (normal range 15-300). On further review of the full blood count you note an MCV of 72.6 (normal range 76-96). The remainder of the full blood count including white blood cell count and platelet count are within normal limits. You refer the patient urgently for colorectal investigation. Which of the following further blood investigations will most likely help determine the underlying cause of this patient’s anaemia?