A blood stem cell or bone marrow transplant is most often the last hope of a cure for many blood cancers and disorders.
Blood cancers such as leukaemia, lymphoma and myeloma can be treated with a blood stem cell transplant.
Donation is almost as simple as giving blood — but finding an HLA-matched donor is the hard part. HLA markers help your immune system tell your own cells from foreign ones.
Most registered donors never get called, because a match is rare — between 1 in 10,000 and 1 in a million. Which is exactly why every extra donor counts.
Fill out a simple form. No needles, no appointments.
5 minutesWe mail you a cheek swab kit with clear instructions.
Within 1 weekSwab your cheek and post it back. All postage prepaid.
2 minutesYou're added to the international donor registry.
DoneThe whole campaign comes down to one remarkable cell. Here's what it does and why a single donor match can rebuild a life.
Blood stem cells are the body's blood-making cells. They live mostly in the soft marrow inside your bones.
They're "unspecialised", which means one stem cell can do two extraordinary things: copy itself, and grow into every type of blood cell your body needs to survive.
The body carefully balances how many of each cell are made, when they mature, and when old cells die.
Your bone marrow makes those master cells and matures them into red cells, white cells and platelets. Normally the whole process is tightly controlled — the right cells, in the right numbers, at the right time.
Leukaemia breaks that control in two ways. Some genetic mutations jam the accelerator, so cells divide relentlessly and ignore the signals that should tell them to stop. Others block maturation altogether, so immature "blast" cells pile up and never become anything useful.
The marrow floods with cells that can't do their job, which is exactly why the illness shows up the way it does:
For people with leukaemia and other blood cancers, transfusions are often essential, not optional. Patients may need repeated transfusions throughout treatment:
Stem cell transplants also depend on healthy donors joining the registry and falling numbers make suitable matches harder to find, especially for Black, Asian and minority-ethnic patients who are already under-represented. For the Kevin Kararwa Leukaemia Trust, that's exactly why we champion both blood donation and stem cell registration, particularly among younger and more diverse communities who can help build a donor base that truly reflects the patients who need it.
Behind every figure is a person waiting for the one match that fits. Here is what the shortage looks like right now.
7 in 10 patients must find an unrelated donor to survive - someone they have never met.
The registry sounds large, but active, available donor numbers are falling worldwide.
Someone, somewhere in the world, is diagnosed with blood cancer. The clock does not stop.
The decline in the UK and many other countries isn't down to one thing, it's a mix of demographic, social and practical pressures, all pulling in the same direction.
Loyal, long-term donors are reaching an age where they can no longer give and younger people aren't stepping in fast enough to replace them.
Packed schedules and competing priorities make it hard to find the time, especially when donating means travel or time off work.
Because shortages are rarely visible, many people assume there's always enough blood or that someone else will give.
The pandemic cancelled sessions and broke long-standing habits. Many donors never returned, and remote working ended the routines that once made city-centre and workplace donation easy.
Safety rules rightly protect patients, but recent travel, some medical conditions, low iron, pregnancy, new medications or a recent tattoo can all rule a donor out, shrinking the eligible pool.
Needles, fainting, or the belief that giving is painful or slow still put first-timers off. In reality, a whole-blood donation takes about 5–10 minutes, with the whole visit around an hour.
Some ethnic communities have historically lower donation rates through low awareness, cultural beliefs, mistrust, language barriers or too little outreach. It matters hugely: patients with conditions like sickle cell often need closely matched blood from donors of similar heritage.
Even as donors decline, demand holds steady or grows — complex surgery, cancer treatment, trauma care, blood disorders and transplants all depend on supply. Every donation counts for more.
Traditional methods reach fewer people. Younger adults respond to social media, creators and digital campaigns far more than to leaflets or post.
With the cost of living high, many people put paid work and caring responsibilities first, even though donating is completely free.
Finding a stem cell match needs very specific genetic compatibility. Because markers vary across ethnic groups, patients from minority backgrounds face far slimmer odds.
Most donors are never matched. But if you are, here's the full journey.
Out of thousands on the registry, your tissue type aligns with a patient's. A coordinator gets in touch.
Further testing checks you're the best available donor. You can ask any question along the way.
A thorough check-up ensures donating is safe for you as well as for the patient.
Peripheral blood stem cell collection takes a few hours as an outpatient. Bone marrow donation (10% of cases) is under anaesthetic.
Your body replaces the donated stem cells within weeks. Travel, accommodation and lost earnings are covered — donation is always voluntary.
If you're ever matched to a patient, the team talks you through both methods and may suggest one - but the final choice is always yours.
Over the four days before donating, you have injections that gently raise the number of stem cells in your blood. You can learn to give these yourself after a single nurse visit (what most donors choose), or have a nurse give all four.
At a specialist centre you relax while connected to a machine - much like giving platelets or plasma. It separates out the stem cells and returns the rest of your blood to you.
Occasionally you're asked back the next day so enough cells are collected, the same easy process - and that's it, you've helped save a life.
In roughly one in ten cases it's best to collect stem cells directly from the hip bones using a thin needle. It's done under general anaesthetic, so you're comfortable throughout.
You stay in hospital for up to 48 hours afterwards for monitoring and pain management.
Plan for around five days of rest as you recover - your energy may be lower than usual while your body heals.
You rest and recuperate while the team keeps in touch to check you're feeling well. Your body replaces the stem cells that were collected within a few weeks to a couple of months, depending on the method.
Stem cell donation is considered very safe. As with any medical procedure there's some small risk and possible temporary discomfort
Donation means painful bone marrow extraction from the hip.
90% of donations are through peripheral blood - very similar to giving blood.
The process takes weeks and requires the donor to be hospitalised.
Most donations are outpatient and take only a few hours.