Irradiated Blood Component Indication Interpreter
Irradiated Blood Component Indication Interpreter
Work out whether this patient needs irradiated cellular components, using the indication list from the 2020 British Society for Haematology guideline. Transfusion-associated graft-versus-host disease is almost always fatal and entirely preventable — and leucodepletion does not prevent it.
Irradiation indicated?
Condition + drug + donationA 68-year-old needing red cells. No condition from the list, no relative or HLA-selected donation — but treated with fludarabine for chronic lymphocytic leukaemia seven years ago
What irradiation does, and what it does not do
Red cells may be irradiated at any time up to 14 days after collection, and stored for a further 14 days from irradiation.
- what it prevents
- transfusion-associated graft-versus-host disease, in which viable donor T lymphocytes engraft in a recipient who cannot reject them and then attack the recipient’s skin, gut, liver and bone marrow. BSH calls it “a rare, usually fatal, complication”; the largest systematic review, of 348 reported cases, found a survival rate of only 8%
- what it costs
- “Both gamma- and X-irradiation of red cells result in significantly accelerated leakage of potassium and an increase in the level of extracellular potassium.” That is why irradiation is targeted rather than universal, and why it matters most in the patients who tolerate it least — a neonate receiving a large volume relative to their size
- the shelf life
- irradiation resets the clock. A unit may be irradiated up to 14 days after collection and then kept only 14 more days, so a component irradiated late in its life expires early. For intrauterine and neonatal exchange transfusion the window closes to 24 hours from irradiation, and washed irradiated red cells should be transfused as soon as possible
- leucodepletion is a different intervention
- universal leucodepletion was introduced to reduce febrile non-haemolytic reactions, HLA alloimmunisation and the theoretical risk of variant CJD transmission — not to prevent TA-GvHD, and it does not. BSH: “There is insufficient evidence to recommend leucocyte depletion alone to prevent TA-GvHD in susceptible patients (1/C).” Of 348 reported cases, 66 (18.9%) were reported between 2000 and 2013, after universal leucodepletion. Holland-Frei, independently: “Cases of TA-GVHD in recipients of filtered components have been reported”
- what is not irradiated
- fresh frozen plasma, cryoprecipitate and fractionated plasma products, which carry no viable lymphocytes — and cryopreserved red cells after deglycerolisation, which BSH names as the one cellular exception
Worked example
A 68-year-old needing red cells. No condition from the list, no relative or HLA-selected donation — but treated with fludarabine for chronic lymphocytic leukaemia seven years ago
Component is cellular, so the plasma exemption does not apply
No relative donation and no HLA-selected platelets, so the donation-based indication does not fire
No listed clinical group — not Hodgkin lymphoma, not a transplant, not a congenital T-cell defect
Fludarabine is a purine analogue → a BSH indication graded 2/C, and it is indefinite
Seven years is not long enough for it to lapse, because purine analogues deplete CD4 lymphocytes profoundly and unpredictably and there is no defined point of recovery
Every other input on this page says no. One line in a clinic letter from seven years ago is the whole answer, which is exactly why this indication is the one most often missed
The useful action is not just to irradiate today's units. It is to get the requirement flagged on the transfusion laboratory system and to give the patient an irradiated blood components card, because the transfusion that goes wrong will be the one at a hospital that has never seen this letter
The BSH 2020 indication list
| Indication | Duration | Grade |
|---|---|---|
| Intrauterine transfusion | The procedure itself; components transfused within 24 h of irradiation | 1/C |
| Top-up transfusion after an intrauterine transfusion | In infancy | 2/C |
| Neonatal exchange transfusion | The procedure; components transfused within 24 h of irradiation | 1/C |
| Severe congenital T-lymphocyte immunodeficiency | Indefinitely — and from suspicion, not from confirmation | 1/B |
| HLA-selected or HLA-matched platelets | Every such component, whatever the recipient’s immune status | 1/B |
| Donation from a first- or second-degree relative | Every such component, whatever the recipient’s immune status | 1/B |
| Allogeneic stem cell transplant | From the start of conditioning; endpoint set by the transplant centre | 1/B |
| Autologous stem cell transplant | 7 days before harvest to 3–6 months after transplant | 1/C |
| CAR-T cell therapy | 7 days before harvest to 3 months after infusion | 1/C |
| Hodgkin lymphoma | Any stage, past or present — indefinitely | 2/C |
| Purine analogues — fludarabine, cladribine, bendamustine, pentostatin | Indefinitely | 2/C |
| Alemtuzumab for CLL or haematological malignancy | Indefinitely | 2/C |
| Aplastic anaemia on anti-thymocyte globulin or alemtuzumab | During and after the therapy | 2/C |
Irradiation and leucodepletion are not the same intervention
| Irradiation | Leucodepletion | |
|---|---|---|
| What it does | Inactivates donor T lymphocytes with 25 Gy so they cannot divide or engraft | Filters leucocytes out of the component to a residual count below a specified threshold |
| What it prevents | Transfusion-associated graft-versus-host disease | Febrile non-haemolytic reactions, HLA alloimmunisation, CMV transmission, and — as the reason for its universal introduction in the UK — the theoretical risk of variant CJD |
| Who gets it | Targeted — only the patients on the indication list | Universal in the UK since 1999, for every component |
| Does it prevent TA-GvHD? | Yes. It is the only thing that does | No. BSH: “There is insufficient evidence to recommend leucocyte depletion alone to prevent TA-GvHD in susceptible patients (1/C)”. 66 of 348 reported cases (18.9%) were reported between 2000 and 2013, after universal leucodepletion |
| Cost to the component | Accelerated potassium leak from red cells; shelf life cut to 14 days from irradiation, and 24 hours for intrauterine and neonatal exchange transfusion | Minimal |
A preventable disease with an 8% survival, and why the blood is not simply irradiated for everyone
Transfusion-associated graft-versus-host disease is what the indication list exists to prevent, and it is worth understanding before the list, because the list makes no sense otherwise. Viable T lymphocytes travel in every cellular blood component. In an ordinary recipient they are recognised as foreign and destroyed within days. In a recipient whose T-cell immunity is severely impaired — or, crucially, in a fully immunocompetent recipient whose donor happens to share an HLA haplotype with them — the donor lymphocytes are not rejected. They engraft, they recognise the recipient as foreign, and they attack the skin, the gut, the liver and the bone marrow. The British Society for Haematology describes it as “a rare, usually fatal, complication of transfusion of blood components containing lymphocytes”. Symptoms begin one to six weeks after the transfusion, at a median of eleven days: rash in around 80% of reported cases, fever in two-thirds, deranged liver enzymes and pancytopenia in about two-thirds each. The largest systematic review of the published cases — 348 of them — found a survival rate of 8%. There is no treatment that reliably works; the marrow failure is the usual cause of death. And it is entirely preventable by a step that takes minutes.
So why not irradiate everything? Because irradiation damages red cells. BSH: “Both gamma- and X-irradiation of red cells result in significantly accelerated leakage of potassium and an increase in the level of extracellular potassium.” That is a real hazard, and the patients in whom it matters most are the smallest ones — a neonate receiving an exchange transfusion is taking a large volume relative to their circulating blood volume, often slowly, and the supernatant potassium of an irradiated unit that has sat for a while can be dangerous. The guideline handles this with a storage rule that has practical teeth: red cells may be irradiated at any time up to 14 days after collection and then stored for only a further 14 days, so a unit irradiated late in its shelf life expires early; and for intrauterine transfusion and neonatal exchange the window shuts to 24 hours from irradiation, with washed irradiated red cells to be transfused as soon as possible. In practice that means the irradiation has to be arranged with the transfusion laboratory in advance of a planned neonatal procedure rather than requested when the baby is on the table, because a unit that was irradiated yesterday morning may no longer be usable this afternoon.
The single most consequential misunderstanding in this area is that leucodepletion covers it. It does not, and the two interventions solve different problems. Universal leucodepletion was introduced in the UK in 1999 to reduce febrile non-haemolytic reactions, HLA alloimmunisation and CMV transmission, and, as the immediate driver, to reduce the theoretical risk of transmitting variant CJD. It filters leucocytes down to a residual count below a specified threshold; it does not reduce them to zero, and the number of lymphocytes needed to cause graft-versus-host disease is very small. BSH states the position plainly: “There is insufficient evidence to recommend leucocyte depletion alone to prevent TA-GvHD in susceptible patients (1/C).” The evidence for that is not theoretical — of the 348 reported cases in the systematic review, 66, or 18.9%, were reported between 2000 and 2013, which is to say after universal leucodepletion, and Holland-Frei records independently that “Cases of TA-GVHD in recipients of filtered components have been reported”. Irradiation is the only intervention that prevents the disease, and a clinician who assumes a leucodepleted unit is adequate for a patient with an indication will simply not ask for irradiation.
Two indications on the list deserve to be singled out because they are the ones that fail in practice. The first is the relative’s donation. Families offer directed donations because it feels safer, and it is more dangerous: a donor homozygous for an HLA haplotype the recipient carries supplies lymphocytes the recipient cannot see as foreign, so they engraft in a person whose immune system is entirely normal. Components from first- and second-degree relatives, and HLA-selected or HLA-matched platelets, must be irradiated regardless of the recipient’s immune status, at grade 1/B. The second is the purine analogue. Fludarabine, cladribine, bendamustine and pentostatin create an indication that never expires, because they deplete CD4 lymphocytes profoundly and with no reliable point of recovery. The failure is never a decision to withhold irradiation; it is that the drug was given years ago, in another hospital, by a team the patient no longer sees, and today’s admitting doctor has no idea. Which means that the most useful thing to do for a patient found to have an indication is not to irradiate today’s units — that part is easy — but to get the requirement flagged on the transfusion laboratory system and to put an irradiated blood components card in the patient’s hand, because the transfusion that goes wrong will be the one somewhere else. If a patient with a suspected indication needs blood before anyone can check, the transfusion reaction interpreter covers what TA-GvHD looks like when it arrives, one to six weeks later.
Frequently asked questions
Which patients need irradiated blood components?
The 2020 British Society for Haematology guideline lists: intrauterine transfusion and the top-up transfusions that follow it; neonatal exchange transfusion; severe congenital T-lymphocyte immunodeficiency, from suspicion rather than confirmation; HLA-selected or HLA-matched platelets; donations from first- or second-degree relatives; allogeneic stem cell transplant recipients from the start of conditioning; autologous transplant from 7 days before harvest to 3–6 months after; CAR-T therapy from 7 days before harvest to 3 months after infusion; Hodgkin lymphoma at any stage, indefinitely; purine analogues — fludarabine, cladribine, bendamustine, pentostatin — indefinitely; alemtuzumab for a haematological malignancy; and aplastic anaemia treated with anti-thymocyte globulin or alemtuzumab. Note what is not on the list: HIV, solid organ transplantation, most chemotherapy regimens, corticosteroids and age alone.
Does leucodepletion prevent transfusion-associated graft-versus-host disease?
No, and this is the most important misunderstanding in the subject. Leucodepletion and irradiation solve different problems. Leucodepletion, universal in the UK since 1999, reduces febrile non-haemolytic reactions, HLA alloimmunisation and CMV transmission, and was introduced primarily to reduce the theoretical risk of variant CJD transmission. It filters leucocytes below a threshold; it does not eliminate them, and very few lymphocytes are needed to cause graft-versus-host disease. BSH states that there is insufficient evidence to recommend leucocyte depletion alone to prevent TA-GvHD in susceptible patients (1/C), and 66 of 348 reported cases — 18.9% — were reported between 2000 and 2013, after universal leucodepletion was in place. Only irradiation prevents it.
Why is blood not irradiated for everyone?
Because irradiation damages red cells. It accelerates potassium leakage across the red cell membrane, raising the supernatant potassium concentration, and it shortens the component’s usable life: a unit may be irradiated any time up to 14 days after collection but may then be stored for only 14 more days. Those two costs are worst in exactly the patients least able to tolerate them — for intrauterine transfusion and neonatal exchange transfusion, components should be transfused within 24 hours of irradiation, and washed irradiated red cells as soon as possible, because a neonate receives a large volume relative to their circulating blood volume. So irradiation is targeted at the patients on the indication list rather than applied universally, and the shortened expiry has to be planned around.
How dangerous is transfusion-associated graft-versus-host disease?
It is almost always fatal. The British Society for Haematology describes it as a rare but usually fatal complication; the largest systematic review, covering 348 reported cases, found a survival rate of only 8%, and a peer-reviewed review of the same literature gives a mortality of more than 90%. Symptoms begin one to six weeks after transfusion at a median of eleven days — rash in about 80% of cases, fever in about two-thirds, deranged liver enzymes and pancytopenia in about two-thirds each — and the marrow failure is what usually kills. There is no reliably effective treatment, which is why the entire clinical effort goes into prevention.
Does a patient who had fludarabine years ago still need irradiated blood?
Yes. The BSH indication for purine analogues — fludarabine, cladribine, bendamustine and pentostatin — is indefinite, because these drugs deplete CD4 lymphocytes profoundly and with no reliable point of recovery, so there is no safe moment at which the requirement lapses. This is the indication most often missed, and the reason is administrative rather than clinical: the drug was given in a different year by a different team, and the doctor requesting blood today has no way of knowing. A patient found to have this indication should have it flagged on the transfusion laboratory information system and should be given an irradiated blood components card to carry, because the transfusion at risk is the one at the next hospital.
Related calculators
References
- Foukaneli T, Kerr P, Bolton-Maggs PHB, et al. Guidelines on the use of irradiated blood components. British Society for Haematology; Br J Haematol. 2020;191(5):704–724. “Transfusion-associated graft-versus-host disease (TA-GvHD) is a rare, usually fatal, complication of transfusion of blood components containing lymphocytes.” “Relevant abnormalities occur 1–6 weeks after transfusion, with the median time from transfusion to first symptom being 11 days.” “The minimum dose achieved in the irradiation volume should be 25 Gy, with no part receiving >50 Gy (1/B).” “Red cells may be irradiated at any time up to 14 days after collection, and thereafter stored for a further 14 days from irradiation.” “Both gamma- and X-irradiation of red cells result in significantly accelerated leakage of potassium and an increase in the level of extracellular potassium.” “There is insufficient evidence to recommend leucocyte depletion alone to prevent TA-GvHD in susceptible patients (1/C).” “It is not necessary to irradiate fresh frozen plasma, cryoprecipitate or fractionated plasma (1/B).”
- Kopolovic I, Ostro J, Tsubota H, et al. A systematic review of transfusion-associated graft-versus-host disease. Blood. 2015;126(3):406–414. 348 reported cases; survival of 8%. Cited and quoted in Transfusion-Associated Graft-Versus-Host Disease in Adults, which gives the general mortality as “>90% of cases” and documents TA-GvHD occurring despite leucodepletion.
- Transfusion-Associated Graft-Versus-Host Disease. In: Holland-Frei Cancer Medicine. NCBI Bookshelf NBK12934. “The majority of reported cases of TA-GVHD have not responded to immunosuppressive therapies and have been fatal.” “Immunocompetent patients who share an HLA haplotype with HLA-homozygous blood donors also appear to be at risk”, and components from such donors should be irradiated with “at least 2,500 cGy”; “products from all family member-directed donors should be irradiated”; “Cases of TA-GVHD in recipients of filtered components have been reported.”
- New HV, Berryman J, Bolton-Maggs PHB, et al. Guidelines on transfusion for fetuses, neonates and older children. British Committee for Standards in Haematology; Br J Haematol. 2016;175(5):784–828.
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