Dr Fitzsimons was Consultant Haematologist at Monklands hospital and Senior Lecturer in Haematology at the University of Glasgow from 1985 to 1996. From 1996 onwards he acted as Senior Lecturer, Consultant Haematologist, and Head of Department at the Western Infirmary and Gartnavel General Hospitals. He is Lead consultant for Anticoagulant Services West Glasgow, Examiner for the Royal College of Pathologists and in charge of Haematology teaching for 3rd year Medical students at Glasgow University.

Between 2002-2008, Dr Fitzsimons was Chair of the West of Scotland Managed Clinical Network in Blood Cancer. In 2010 he was appointed Head of Laboratory Haematology in NHS Greater Glasgow and Clyde, and in 2012 he became Clinical Director of Laboratory Medicine for the Golden Jubilee National Hospital which provides specialist Ophthalmic, Cardiac, Respiratory and Orthopaedic services. In 2014 he was appointed Honorary Associate Clinical Professor at the University of Glasgow. Dr Fitzsimons also became Medical Advisor to Haemochromatosis UK in 2014 and Lead Author for the British Society of Haematology Guidelines for Genetic Haemochromatosis in 2018.

Dr Fitzsimons also has more than 60 peer reviewed research publications in scholarly journals, with major clinical and research interests in Genetic Haemochromatosis and in the many different Anaemias.

• General haematology
• Genetic haemochromatosis
• Anemias
• Iron, vitamin B12 and folate deficiencies
• Abnormalities of platelets and white blood cells
• Disorders of coagulation, blood clotting and anticoagulants
• Investigation and diagnosis of lymphadenopathy and splenomegaly

• British Medical Association
• General Medical Council
• British Society for Haematology
• Fellow of Royal College of Physicians UK
• Fellow of Royal College of Pathologists UK