Alterations in HbAlc resulting from the donation of autologous blood for elective surgery in patients with diabetes mellitus

Background. The aim of this study was to confirm the change in haemoglobin A1c consequent to pre-operative donation of autologous blood for elective surgery in patients with diabetes mellitus. Material and methods. For enrolment in this prospective study, patients had to be scheduled for multiple autologous blood donations at different times and have a haemoglobin A1c level more than 5.8% at the first donation. The values of four factors, haemoglobin, haemoglobin A1c, glycated albumin, and glycated albumin/haemoglobin A1c ratio were determined. Changes in the values of these four factors between before and after the blood donations were calculated. Results. In all 24 patients studied, haemoglobin and haemoglobin A1c decreased as a result of the autologous blood donations. The group with a reduced glycated albumin/haemoglobin A1c ratio had short intervals between blood donations. Correlations were observed between donation interval and change in haemoglobin A1c (r=0.63, P=0.003), and between donation interval and change in the glycated albumin/haemoglobin A1c ratio (r=0.489, P=0.045). Discussion. Haemoglobin A1c levels are likely to be underestimated after autologous blood donation by patients with diabetes mellitus, so glycated albumin may be a better indicator of these patients' glycaemic control.