Glycosylated haemoglobin (HbA1c) is a measurement commonly performed in patients with diabetes. Factors causing a change in the life span of the red blood cell (RBC) can affect the measurement of HbA1c. Thus haemolysis is an important factor that may affect the HbA1c level determination. Haemolysis has been shown to cause a falsely low HbA1c. A 62-year-old man with a history of autoimmune haemolytic anaemia was admitted for severe haemolytic anaemia and an Hb of 2.9 g/dL. HbA1c tested during hospitalisation was unrecordable due to the extremely low Hb. The patient was treated with intravenous steroids, immunoglobulin, fluids and RBC transfusions but continued to haemolyse and eventually expired. We emphasise that an extremely low HbA1c level can serve as a marker of haemolysis and an unrecordable HbA1c level may point towards fatal haemolysis.