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During cancer treatment your red cells or platelets may fall. Blood or platelet transfusions are given when the levels fall below set points, or when you are bleeding, rather than to bring the numbers back to normal. Giving less blood at higher thresholds has proved just as safe in trials, and spares people the risks of transfusion.
For red cells, NICE NG24 recommends a restrictive threshold for people without major haemorrhage, acute coronary syndrome or regular transfusion for chronic anaemia: consider transfusing at haemoglobin 70 g/L, aiming for 70 to 90 g/L afterwards, with a threshold of 80 g/L and target 80 to 100 g/L in acute coronary syndrome. AABB (2023) suggests the same 7 g/dL threshold for hospitalised adults with haematological and oncological disorders (conditional, low certainty), within its strong recommendation for stable hospitalised adults generally; clinicians may use 8 g/dL with pre-existing cardiovascular disease. Give single units to adults who are not bleeding, and reassess after each.
For platelets, prophylactic transfusion is given below 10 × 10⁹/L in people not bleeding and not having procedures (NICE; AABB/ICTMG 2025 strong recommendation for chemotherapy and allogeneic transplant), with no routine prophylaxis in chronic bone marrow failure, immune thrombocytopenia, heparin-induced thrombocytopenia or TTP. Adults having autologous transplant may be transfused at the first sign of bleeding rather than prophylactically (ASCO 2018; AABB/ICTMG 2025 conditional). For bleeding, NICE offers platelets for WHO grade 2 bleeding below 30 × 10⁹/L and allows up to 100 × 10⁹/L for severe or critical-site bleeding. Before procedures, NICE considers raising the count above 50 × 10⁹/L (100 × 10⁹/L for the central nervous system or back of the eye), while AABB/ICTMG (2025) set lower thresholds for some, such as 10 × 10⁹/L for central venous catheters in compressible sites and 20 × 10⁹/L for lumbar puncture. Give a single dose and recheck.
Why: Trials found that transfusing at a lower haemoglobin is as safe as transfusing at a higher one, and avoids unneeded blood.
“Use restrictive red blood cell transfusion thresholds for people who need red blood cell transfusions and who do not: have major haemorrhage or have acute coronary syndrome or need regular blood transfusions for chronic anaemia.”
Why: This is the threshold used in most trials and in both NICE and AABB.
“When using a restrictive red blood cell transfusion threshold, consider a threshold of 70 g/litre and a haemoglobin concentration target of 70 to 90 g/litre after transfusion.”
Why: AABB looked at people with haematological and oncological disorders separately and suggests the same threshold, on weaker evidence.
“Recommendation 2: for hospitalized adult patients with hematologic and oncologic disorders, the panel suggests a restrictive transfusion strategy considering transfusion when the hemoglobin concentration is less than 7 g/dL (conditional recommendations, low certainty evidence).”
AABB, JAMA 2023 · conditional recommendation, low certainty evidence
Why: One unit is often enough, and each extra unit adds risk.
“Consider single‑unit red blood cell transfusions for adults (or equivalent volumes calculated based on body weight for children or adults with low body weight) who do not have active bleeding.”
Why: This is the threshold both NICE and AABB/ICTMG use for people who are not bleeding; transfusing at higher counts adds risk without shown benefit.
Why: In these conditions the low count has other causes and its own treatment; NICE advises against routine prophylaxis.
“Do not routinely offer prophylactic platelet transfusions to people with any of the following: chronic bone marrow failure autoimmune thrombocytopenia heparin‑induced thrombocytopenia thrombotic thrombocytopenic purpura.”
Why: Randomised trials in this group showed that a bleeding-triggered approach is reasonable.
“Based on data from randomized controlled trials, adult patients who undergo autologous stem-cell transplantation at experienced centers may receive a platelet transfusion at the first sign of bleeding, rather than prophylactically.”
Why: Bleeding in the brain or eye is dangerous at counts that would otherwise be safe.
Why: These procedures rarely bleed, and the platelets carry their own risks.
“Do not offer prophylactic platelet transfusions to people having procedures with a low risk of bleeding, such as adults having central venous cannulation or any people having bone marrow aspiration and trephine biopsy.”
Why: One dose is usually enough; more doses add risk without benefit except in severe bleeding at a critical site.
“Do not routinely transfuse more than a single dose of platelets.”
How care is usually carried out, read from the guidelines and standards cited. Your own team's protocol and their judgement come first; this page is for understanding it, not for doing it yourself.
NICE NG24 and AABB agree on restrictive thresholds. For red cells both use 70 g/L (7 g/dL); AABB's 2023 recommendation for people with haematological and oncological disorders is conditional on low-certainty evidence, while its recommendation for stable hospitalised adults overall is strong. For prophylactic platelets both use 10 × 10⁹/L in people having chemotherapy or allogeneic transplant (AABB/ICTMG 2025, strong, high or moderate certainty). They differ on procedures: NICE considers a count above 50 × 10⁹/L before invasive procedures generally and advises against platelets for central venous cannulation, whereas AABB/ICTMG (2025) set procedure-specific thresholds (10 × 10⁹/L for central lines in compressible sites, 20 × 10⁹/L for lumbar puncture and low-risk interventional radiology, 50 × 10⁹/L for high-risk interventional radiology and major non-neuraxial surgery). On autologous transplant, ASCO (2018) and AABB/ICTMG (2025, conditional) support a bleeding-triggered rather than prophylactic approach in adults.
NICE 2015 · NICE 2015 · AABB, JAMA 2023 · AABB and the International Collaboration for Transfusion Medicine Guidelines, JAMA 2025 · ASCO, Journal of Clinical Oncology 2018
Where it differs: Sets thresholds by procedure: below 10 × 10⁹/L for central venous catheters in compressible sites, below 20 × 10⁹/L for lumbar puncture and low-risk interventional radiology, below 50 × 10⁹/L for high-risk interventional radiology and major non-neuraxial surgery.
Evidence: GRADE; strong with high or moderate certainty for lumbar puncture, conditional with low or very low certainty for the others; read as an abstract.
AABB and the International Collaboration for Transfusion Medicine Guidelines, JAMA 2025
Where it differs: Allows 8 g/dL for people with pre-existing cardiovascular disease or having orthopaedic surgery, and 7.5 g/dL in cardiac surgery, in line with the trials' restrictive arms; NICE uses 80 g/L only for acute coronary syndrome.
Evidence: AABB recommendation 1, strong, moderate certainty; read as an abstract.
| Recommendation | Grade, as printed | Source |
|---|---|---|
| Restrictive red cell threshold (7 g/dL) for stable hospitalised adults | strong recommendation, moderate certainty evidence (GRADE) | AABB, JAMA 2023 |
| Restrictive red cell threshold (7 g/dL) for adults with haematological and oncological disorders | conditional recommendation, low certainty evidence (GRADE) | AABB, JAMA 2023 |
| Platelets below 10 × 10⁹/L for non-bleeding people on chemotherapy or having allogeneic transplant | strong recommendation, high or moderate certainty (GRADE) | AABB and the International Collaboration for Transfusion Medicine Guidelines, JAMA 2025 |
| No prophylactic platelets for non-bleeding adults having autologous transplant or with aplastic anaemia “For hypoproliferative thrombocytopenia in nonbleeding adults undergoing autologous stem cell transplant or with aplastic anemia, prophylactic platelet transfusion is not recommended.” | conditional recommendation, low or very low certainty (GRADE) | AABB and the International Collaboration for Transfusion Medicine Guidelines, JAMA 2025 |
Shares Thrombocytopenia, Transfusion support and anaemia management, National Institute for Health and Care Excellence and the tags protocol, transfusion.
Shares National Institute for Health and Care Excellence, American Society of Clinical Oncology (ASCO) and the tags protocol, supportive-care.
Shares National Institute for Health and Care Excellence, American Society of Clinical Oncology (ASCO) and the tags protocol, supportive-care.
Shares National Institute for Health and Care Excellence, American Society of Clinical Oncology (ASCO) and the tags protocol, supportive-care.
Shares National Institute for Health and Care Excellence, American Society of Clinical Oncology (ASCO) and the tags protocol, supportive-care.
Shares National Institute for Health and Care Excellence and the tags protocol, supportive-care.
Shares American Society of Clinical Oncology (ASCO) and the tags protocol, supportive-care.
Shares American Society of Clinical Oncology (ASCO) and the tags protocol, supportive-care.