Appeal for O-type blood donors intensifies following a cyber attack that has impacted hospitals in London.

Several London hospitals declared a critical incident, leading to the cancellation of operations, tests, and blood transfusions.

An appeal has been made for O blood-type donors to schedule appointments nationwide due to a ransomware attack impacting major London hospitals.

NHS Blood and Transplant urgently appeals to O blood-type donors to schedule donations, as the recent IT attack has disrupted the hospitals’ ability to match patients’ blood at the usual frequency.

Several London hospitals declared a critical incident and had to cancel operations and tests, as well as being unable to carry out blood transfusions this week following an attack on the pathology firm Synnovis, believed to have been orchestrated by the Russian cyber criminal group Qilin.

Memos to NHS staff at King’s College Hospital, Guy’s and St Thomas’ (including the Royal Brompton and the Evelina London Children’s Hospital) and primary care services in London declared a critical incident.

NHS Blood and Transplant seeks O-Positive and O-Negative blood donors to schedule appointments at one of the 25 NHS Blood Donor Centres in England in order to increase blood supplies.

NHS Blood and Transplant reported that hospitals affected by the cyber attack are currently unable to match patients’ blood at the usual frequency.

Hospitals require O type blood for surgeries and procedures, as it is safe for all patients. Blood has a shelf life of 35 days and stocks need continual replenishment, according to the NHS.

More units of O-negative blood will be needed in the upcoming weeks as it can be transfused to anyone, making it the universal blood type.

O negative blood is in high demand for emergencies and when the patient’s blood type is unknown, with air ambulances and emergency vehicles carrying supplies. Although only 8% of the population has type O Negative, it constitutes around 15% of hospital orders.