Health officials have issued an urgent appeal for blood donors to step forward following a "triple whammy" of surging demand, lower collection rates and the challenges posed by hot weather.
The NHS Blood and Transplant (NHSBT) division said increasing donor numbers will help ensure national blood reserves are in a stronger position to "withstand" routine summer "shocks" to the system.
It comes following various heatwaves in the UK - which directly affect eligibility, as even mildly warmer weather is capable of reducing a donor's iron levels.
NHSBT reported that donations can decrease by 10 per cent on ordinary warm days as a result.
Warm weather can also contribute to dehydration which will impact donors, while summer holidays, childcare responsibilities and deferrals for people returning from trips abroad continue to disrupt regular collection appointments.
Meanwhile, some patients reliant on routine transfusions could require a higher volume of blood than usual due to warmer conditions. NHSBT said that it has seen higher demand from hospitals during the heatwaves in June and July.
Darren Bowen, assistant director for blood supply at NHSBT, said: “This summer has been a particularly challenging one for the blood service in England – with blood stocks hit by the triple whammy of hot weather, holidays and high demand from hospitals.
“With hot weather arriving earlier and lasting much longer than we have seen in recent years, it has resulted in lower collections along with increased demand from hospitals, with many patients reliant on regular transfusions for conditions like sickle cell needing more frequent treatment, or higher quantities of blood, than usual.
“We urge donors, especially those with B negative, O negative and the Ro subtype, as well as more donors of black heritage, to keep coming forward as we work to rebuild stocks.”
It comes as blood supply organisations across England, Canada and Australia have come together for the first time to launch an appeal for more blood donors across the three countries as a range of pressures have impacted blood supplies.
These include extreme weather and seasonal illness to changing donation patterns, NHSBT said.
The organisation has previously issued an urgent call for donors to fill 60,000 appointments over the summer period.
It has joined forces with Australian Red Cross Lifeblood and both Canadian Blood Services and Hema-Quebec in Canada to highlight the growing demand for blood because of ageing populations leading to more people living with conditions such as cancer and sickle cell that require regular blood transfusions for treatment.
Meanwhile, demand for medicines made from plasma to treat immune deficiencies, bleeding disorders and other conditions continues to rise, it said.
Across the three countries, blood supplies have dropped up to 30% in recent months, NHSBT added.
Gerry Gogarty, director of blood and plasma supply at NHS Blood and Transplant, said with millions globally depending on blood transfusions for surgeries, trauma, cancer treatment and chronic disease, disruption to regular donation is a challenge all three countries face.
“Blood collection systems are vulnerable to changing weather and climate, including heatwaves in summer and cold and flu outbreaks in winter, but regular donors are the foundation of a resilient supply,” Mr Gogarty said.
“By boosting the number of donors, particularly those with key blood types including O negative, B negative and the RO subtype needed to treat sickle cell, we can better withstand these shocks and ensure we are prepared for a future where events like this may happen more often.”
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