Hospitals have been asked to postpone non-urgent surgery after NHS Blood and Transplant (NHSBT) declared its first-ever amber alert status due to low blood supplies.
A spokeswoman for the service said current overall blood stocks in the NHS stand at 3.1 days but levels of O type blood have fallen to below two days.
The amber alert will last initially for four weeks which should enable blood stocks to be rebuilt, NHSBT said in a statement.
O negative blood is the universal blood type which can be given to everyone. It is vitally important during emergencies and when the blood type of the recipient is unknown.
Around one in seven (13 per cent) of Britons have O negative blood. Air ambulances and emergency response vehicles also carry O negative supplies for emergencies.
NHSBT urged Londoners to donate blood at centres in Stratford and Tooting, where there hundreds of spare appointments.
The current amber alert is also thought to be due to ongoing staffing issues, with more staff needed to work at donor sessions.
Hospitals have been advised to swap in other elective surgery that doesn’t require blood and put in place management plans to protect blood stocks, NHSBT said.
NHSBT has urged donors to help by filling empty appointments at permanent donor centres in towns and cities which have extended hours and greater capacity.
Wendy Clark, Interim Chief Executive of NHS Blood and Transplant said: “Asking hospitals to limit their use of blood is not a step we take lightly. This is a vital measure to protect patients who need blood the most.
“Patients are our focus. I sincerely apologise to those patients who may see their surgery postponed because of this.
“With the support of hospitals and the measures we are taking to scale up collection capacity, we hope to be able to build stocks back to a more sustainable footing.
“We cannot do this without our amazing donors. If you are O Positive or O Negative in particular, please make an appointment to give blood as soon as you can. If you already have an appointment, please keep it.”
NHSBT said maintaining blood stocks has been an ongoing challenge in the aftermath of the Covid pandemic, mainly due to staff shortages and sickness but also due to the fact people are less likely to visit collection centres in towns and cities.
Action currently being taken to tackle the issue includes moving more staff to the front line to open up more appointments, speeding up recruitment to fill vacant posts and using agency staff, as well as retaining existing workers.
Blood can only be stored for 35 days, which means there is a constant need for donations - and a need for specific blood types.