Demand for blood needed to treat rare disorders such as sickle cell has soared by more than 130% in 10 years, forcing the NHS to ask for more donors to come forward.

Requests for haemoglobin S (HbS)-negative blood, the type most used in blood transfusions for sickle cell anaemia patients, stood at 82,181 units in 2015. But last year, more than 191,000 units were needed, a 132% increase.

HbS is a type of haemoglobin commonly found in people with sickle cell trait and sickle cell disorder. It gives red blood cells a crescent or ‘sickle’ shape, reducing the flexibility of the cells in blood vessels.

For transfusions, patients with sickle cell should receive blood that does not contain HbS.…