Anaemia is a common condition affecting approximately 30% of surgical patients, with iron deficiency being the leading cause (Musallam et al, 2011). The World Health Organization historically defined anaemia as a haemoglobin concentration of less than 120 g/litre for women and 130 g/litre for men. However, a more recent international consensus statement on management of perioperative anaemia has suggested using 130 g/litre for both men and women (Muñoz et al, 2017).