Restrictive haemoglobin thresholds and single unit blood transfusions toolkit

This page contains information for clinical and laboratory transfusion staff to support restrictive transfusion and a single unit approach to blood transfusion.

Patient blood management strategies are paramount to optimise patients' own red cells and avoid transfusion where possible.

However, where transfusion is unavoidable, restrictive haemoglobin thresholds and a single unit approach should be adopted.

Using restrictive haemoglobin (Hb) thresholds and targets for red blood cell transfusions, and transfusing one unit at a time, minimises inappropriate transfusion and reduces serious risks such as transfusion-related circulatory overload (TACO). It also improves patient outcomes, reduces hospital costs, and preserves blood stocks.

These guidelines apply to all patients apart from those with major bleeding and those requiring regular red cell transfusion or exchange transfusion.

In this section

Pages in the 'Appropriate use of blood components' section

Guidance

Use this guidance from the National Institute for Health and Care Excellence (NICE) to ensure the safe and appropriate use of blood components:

Indication codes for transfusion are available to download on the National Blood Transfusion Committee (NBTC) recommendations page:

NBTC recommendations

Recommendations

Examples of good practice

The PBM team has worked collaboratively with multiple hospitals, developing resources to support the implementation of a single use policy.

Our 2014 pilot project with King's College Hospital introduced a single unit transfusion policy for non-bleeding medical patients in an acute medical unit. This resulted in a 40% to 45% reduction in red cell use over a 6-month period.

In 2018 the PBM Team ran a number of projects with hospitals and developed resources which may help other hospitals to implement a single use policy.

Use these resources to help your hospital achieve similar success.

Royal Derby Hospital:

Resources

Use these resources to support the implementation of a single unit policy within your organisation:

Research and publications

The links below are to research publications related to restrictive transfusion in different clinical settings.

A Restrictive Versus a Liberal Transfusion Strategy in Patients With Spontaneous Intracerebral Hemorrhage: A Secondary Analysis of TRAIN Randomized Clinical Trial - published on the JAMA network website

Comparison of safety and efficacy of li beral versus restrictive red blood cell transfusion thresholds on the quality of life in patients with myelodysplastic syndromes: a systematic review and meta-analysis - on the National Library of Medicine website

Effects of liberal versus restrictive transfusion strategies on intermittent hypoxaemia in extremely low birthweight infants: secondary analyses of the ETTNO randomised controlled trial Published in  Archives of Disease in Childhood: Fetal and Neonatal Edition - BMJ Journals website

Liberal or restrictive transfusion for veno-arterial extracorporeal membrane oxygenation patients: a target trial emulation using the OBLEX study data - Critical care journal, National Library of Medicine website

Liberal versus restrictive red blood cell transfusion strategy in acute coronary syndrome and anemia: an updated systematic review and meta-analysis - Frontiers in cardiovascular medicine, National Library of Medicine website

Liberal versus restrictive red blood cell transfusion thresholds in acute acquired brain injury: a systematic review and meta- analysis - BMJ Open Access website

Restrictive versus Liberal blood transfusion strategies for patients undergoing orthopedic surgery: a meta-analysis of randomised trials with trial sequential analysis - published in Journal of Orthopaedic Surgery and Research, on the Springer website

How low can we go? Comparison of liberal and restrictive red cell transfusion thresholds in paediatric allogeneic haematopoietic stem cell transplantation: A randomized multicentre feasibility trial - British Journal of Haematology, on the Wiley online library website

Infographics

These infographics are designed for you to use alongside appropriate text in presentations and educational resources. Please acknowledge the NHS Blood and Transplant Patient Blood Management team as the author.

Don't give two without review

Graphic showing two units of blood that are crossed out, with text advocating for a single-unit transfusion approach

Text reads: "Single unit transfusions reduce the risk of an adverse reaction and may be suitable for the following adults:

Clinically stable
Normovolaemic
No evidence of clinically significant active bleeding

Clinically reassess the person after each unit has been transfused:

Are there any signs or symptoms of transfusion reaction?
Have their symptoms of anaemia improved?
Re-check haemoglobin levels - is a further unit indicated?"

Download the single unit transfusion infographic (PDF 1,041 KB)

Download the single unit transfusion infographic (PPTX 560KB)

Share your learning

Tell us about your single unit blood transfusions projects, highlighting your successes or where things didn't go so well, and we'll include them on this page.

Page last reviewed: August 2026