Health officials are urging more black people to give blood, to meet a growing demand for a special subtype of blood.
NHS Blood and Transplant (NHSBT) said that 40,000 more black donors are needed, after the amount of Ro blood issued to hospitals in England rose by 75% between 2014 and 2016.
Ro blood is more common in people with an African or Caribbean family background.
A high proportion of Ro blood, which is a subtype of the Rhesus blood group, is used to treat sickle cell disease.
The condition, which affects around 15,000 people in the UK, is particularly common in black people.
Sickle cell disease can be extremely painful and sufferers are at higher risk of developing life-threatening conditions, having strokes and losing their vision.
But blood transfusions can relieve or prevent these symptoms.
One woman who is particularly grateful to black donors is Omotolani Olabifi.
Her son Matthew Akinmuleya was diagnosed with sickle cell at birth.
Ever since his diagnosis, the ten-year-old from London has required a blood transfusion every month.
Ms Olabifi said: ‘The hospital tried to see if he could manage without blood transfusions, but he had so much pain, A&E admissions, IV and oral morphine. Nothing could help.
‘The blood he receives makes a huge difference. In the first two weeks after his transfusion he is like a normal 10-year-old. He has energy and is able to go to school.
‘But after three weeks, he starts to look pale, jaundiced, tired and pain takes over. In the week before his transfusion, he will be in severe pain and often admitted to hospital.’
She added: ‘As a mother and carer, I really appreciate all of those who donate. My child would not have survived without you.
‘We need the help for our children to help them live. Without this blood, his story would be so different.’
To ensure patients receive the best treatment, blood matches must be as close as possible.
This means blood from someone of the same ethnicity is more likely to produce a better outcome.
But NHSBT said just 1% of people who give blood in England are black.
To mark National Blood Week, NHSBT has launched a new campaign – £ImThere – to try to encourage more donors to register and donate.
Mike Stredder, director of blood donation, NHS Blood and Transplant, said: ‘We need to ensure that we have the right mix of donors and blood types, to help meet the needs of all patients who need life-saving treatment, especially those with conditions like sickle cell disease who require blood which is more closely matched than by group alone.
‘In recent weeks, we have been overwhelmed by the numbers of people stepping forward and wanting to donate and show their support for those affected by recent tragic events.
‘Thankfully, due to the loyalty of our regular donors, our emergency stocks have proven to be strong and sufficient, but we still need to ensure that we can be there every day, for every patient who needs us.’