Sickle-cell disease is a collective term for disorders resulting from the presence of sickle haemoglobin. Sickle trait, heterozygous state for sickle haemoglobin is relatively benign however laboratories are increasingly requested to carry out tests to detect the presence of sickle haemoglobin (HbS) on immigrant patients, particularly before any form of surgery. Sickle-cell thalassaemia and sickle-cell haemoglobin C disease have an intermediate severity. Sickle-cell anaemia, the homozygous state for sickle haemoglobin, varies in its severity according to its geographical location and is commonly associated with childhood death.