Medical Oncologist
CION Cancer Clinics
Testing a relative before a family stem cell donation | CION Cancer Clinics
If a leukaemia may be inherited, a brother, sister or parent offering stem cells is tested for the same gene fault before being chosen as the donor. The test protects the patient from receiving cells that carry the risk, and tells the donor something about their own health. This page explains which checks a family donor has, the order they happen in, and what each result means. At CION Cancer Clinics, our oncologists plan screening and care for families with an inherited cancer syndrome, explained in plain words.
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Medically reviewed by Dr. Basudev PokhrelConsultant Haematologist · last reviewed September 2026, next review due September 2027
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On this page
- Why would a relative need a gene test before donating stem cells?
- Which checks does a family donor have?
- What happens, and in what order?
- The transplant terms, in plain language
- Tissue typing and gene testing ask different questions
- Four things families tell us, and what is actually true
- What this page cannot tell you
- Common questions about testing a family donor
The short answer
Why would a relative need a gene test before donating stem cells?
Because the relative may carry the same inherited fault that raised the patient's risk of leukaemia. If an inherited cause is known or suspected, each family donor is tested for that fault before being chosen. It adds a step, and it protects both the patient and the donor.
What a family stem cell donation is
In a stem cell transplant, healthy blood-making cells from a donor replace the patient's diseased bone marrow. A fully matched brother or sister is often the first choice. In India, half-matched donation from a parent, child or sibling is also common, because registries hold fewer Indian donors than families would hope.
When the genetic step is added
Most family donors never need a gene test. The step is added when the patient already has a known inherited fault, or when there are clues. The patient may have been diagnosed young, have a relative with leukaemia or lifelong low platelets, or have a marrow report that hints at an inherited fault. The transplant team decides whether those clues are strong enough.
Every donor also has routine health and infection checks. The gene test is extra, not a replacement.What the donor goes through
Which checks does a family donor have?
Four kinds of check, each answering a different question. Only the last one is about inherited risk.
Tissue typing
A cheek swab or blood test compares the donor's tissue type, called HLA, with the patient's. It tells the team how well matched they are. It says nothing about leukaemia risk.
Health and infection checks
Blood tests for infections such as hepatitis and HIV, a heart check and a general examination. These make sure donation is safe for the donor and that no infection passes to the patient.
Blood counts and a blood film
A low platelet count or unusual cells in a healthy-looking donor can be the first sign that something is shared. It is a quick test with a lot to say.
A gene test for the family fault
Done only when a fault is known or suspected. Because the donor does not have leukaemia, an ordinary blood sample usually works.
It tells the team
- Whether this donor can safely be used
- Whether the donor needs monitoring themselves
- Whether other relatives should be tested
Not sure whether this applies to you?
Ask an oncologistStep by step
What happens, and in what order?
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The patient's own inherited test starts early
For someone with leukaemia, this is often done on a small skin sample grown in the laboratory, which can take several weeks. Starting it at diagnosis avoids a delay later.
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Brothers, sisters and parents are tissue typed
This finds out who is a full or half match. Relatives who are not a match usually need no gene test for donation purposes.
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Each matched relative is counselled first
A gene test tells the donor about their own health, not only about the transplant. A counsellor explains that before any sample is taken.
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The gene test runs alongside a registry search
The team often searches for an unrelated donor at the same time, so a carrier result does not leave the patient waiting.
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The donor is chosen
A relative who does not carry the fault goes on to the standard donor work-up. A relative who does carry it is usually not used, and is offered their own follow-up.
Words you will hear
The transplant terms, in plain language
- Allogeneic transplant
- A transplant using stem cells from another person. Family donations are this type.
- HLA or tissue type
- Markers on your cells that the immune system uses to tell self from non-self. A closer match means fewer problems after transplant.
- Half-matched donor
- A relative who shares half the tissue type. Doctors call this haploidentical. Parents and children are always at least a half match.
- Carrier
- Someone who has the inherited fault. A carrier is not ill, but is usually not used as a donor for a relative.
- Donor registry
- A list of volunteers willing to donate to a stranger. Indian and international registries are searched when no family donor is suitable.
- Germline test
- A test for a fault present from birth in every cell. It is different from the marrow tests done on the leukaemia itself.
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Side by side
Tissue typing and gene testing ask different questions
Tissue typing asks
The gene test asks
Will the patient's body accept these cells?
Could these cells carry the same risk?
Done for every possible family donor
Done only when a fault is known or suspected
The result is about the transplant
The result is also about the donor's own health
A cheek swab or blood sample
Usually a blood sample from the donor
Commonly believed
Four things families tell us, and what is actually true
"If I am a match, I have no choice but to donate."
Donation is always voluntary. A donor can say no at any stage, including to the gene test. Many transplant centres give donors their own doctor, separate from the patient's team, so the decision is truly theirs.
"The gene test will delay the transplant."
It need not, when it is started early and run alongside the registry search. Delays usually happen when the question is raised late, after a donor has already been chosen.
"If I carry the fault, I will get leukaemia too."
A carrier has a raised risk, not a certainty. Many carriers stay well. Knowing means you can have regular blood counts, so any change is found early.
"An unrelated donor is always second best."
A well-matched unrelated donor is a standard option. A related donor who carries the fault is not a safer choice just because they are family.
Being straight with you
What this page cannot tell you
It cannot tell you whether your relative can donate. That decision belongs to the transplant team, who weigh the match, the donor's health, the gene result and how urgent the transplant is. Every family's situation is different.
It cannot interpret a donor's result
Gene tests sometimes return a variant the laboratory cannot yet classify. What a specific variant means for donation is a question for the counsellor who ordered the test and the transplant team together. The donor's result belongs to the donor. Ask how it will be shared, and with whom, before the sample is taken.
Who this does not apply to
Most families going through a transplant do not need donor gene testing. When the leukaemia shows no inherited clues, the standard tissue typing and health checks are enough. Evidence on how best to screen related donors is still growing, and practice differs between centres.
If you are unsure whether your family needs this step, ask the transplant team directly. It is a reasonable question at any stage.Questions we are asked
Common questions about testing a family donor
Why not simply use the best-matched sibling?
A perfect tissue match can still carry the same inherited fault as the patient. Cells from that donor could bring the risk back into the patient's new marrow. So when a fault is suspected, the match is checked for it first.
Does the donor need a skin sample too?
Usually not. The skin route is for the patient, whose blood contains leukaemia cells. A healthy donor's blood is normally reliable for the gene test, so a routine blood sample is enough in most cases.
How long does the donor's gene test take?
Testing a relative for one known fault is usually quicker than a full panel. Exact timing varies by laboratory. Ask the team for their current turnaround, and start early so the result is ready when a donor is needed.
What if every matched relative carries the fault?
The team turns to an unrelated donor from a registry, or to other donor options they consider suitable. This is why the registry search is often started at the same time as family testing.
Can a relative refuse the gene test?
Yes. Nobody can be made to take a gene test. When an inherited fault is suspected, a relative who declines is usually not used as the donor. A counsellor can talk through that choice without pressure.
Who pays for the donor's tests?
It depends on the centre, the transplant package and any insurance or government scheme. Ask the transplant coordinator whether donor tests are included, and whether Aarogyasri or Ayushman Bharat covers any part of them.
Will the rest of the family be told the donor's result?
Not without the donor's agreement. The result is about the donor's own health. A counsellor can help the donor decide whether and how to tell brothers, sisters or their own children, who may also want testing.
Where do we start?
Ask the haematologist whether an inherited cause has been considered, and whether the patient's own test has been sent. Then list every brother, sister, parent and adult child who may be willing to donate. The CION helpline can point you to the right team.
Your Specialists
Meet CION's oncologists. Bring your family history or genetic report to them.
Our medical oncologists see people with a strong family history of cancer, arrange genetic counselling and testing where it fits, and plan the checks that follow.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
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Sources
- National Cancer Institute — Stem Cell Transplants in Cancer Treatment
- NHS — Stem cell and bone marrow transplants
- GeneReviews (NCBI) — RUNX1 Familial Platelet Disorder with Associated Myeloid Malignancies
- GeneReviews (NCBI) — CEBPA-Associated Familial Acute Myeloid Leukemia (AML)
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
Why a related donor must be screenedThe reasons behind the extra step, in more depthInherited predisposition to leukaemia and MDSWhich gene faults raise the risk in the first placeClues that a blood cancer may be inheritedWhat makes a transplant team suspect an inherited causeRUNX1 and donor selectionHow one well-known gene changes the donor decision
Talk to us
Is a relative about to be tested as a stem cell donor?
Tell us what the transplant team has said and who in the family has offered to donate. We will explain the next steps and whether genetic counselling should come first. One helpline serves every CION centre.