[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Immunology](https://durgical.com/en/immunology/) › [Hypersensitivity](https://durgical.com/en/immunology/#a-hypersensitivity) › Transfusion reactions

[Immunology](https://durgical.com/en/immunology/) · [Hypersensitivity](https://durgical.com/en/immunology/#a-hypersensitivity)

# Transfusion reactions

- Topic

Harmful reactions to a blood transfusion, from fever and hives to a deadly blood-type mismatch. Most serious ones start in the first minutes.

Updated 2026-11-01

**See it in 3D:** [Kidneys](https://durgical.com/en/anatomy/kidney/)

## Key points

- First nursing action for any suspected reaction: stop the transfusion and keep the line open with normal saline.
- Acute hemolytic reaction = ABO mismatch, usually a clerical or identification error: fever, flank pain, dark urine, hypotension.
- Anaphylaxis without fever in a patient with IgA deficiency: anti-IgA antibodies.
- TRALI versus TACO: both cause dyspnea; TACO has hypertension and fluid overload, TRALI does not.
- Delayed hemolytic reaction: days later, falling hemoglobin and positive direct Coombs.
- Irradiated blood prevents transfusion-associated graft-versus-host disease.

## What it is

A transfusion reaction is any harmful event caused by blood or one of its components. Acute reactions start during the transfusion or within hours; delayed ones appear days to weeks later. The most feared, an acute hemolytic reaction, is usually an ABO mismatch caused by an identification error at the bedside, which is why checking the patient and the unit is the main safety step. Whatever the cause, the first move is the same: stop the transfusion.

## Step by step

- Stop the transfusion at the first sign of a reaction.
- Keep the vein open with normal saline through new tubing; never flush the rest of the blood in.
- Check vital signs and airway; call for help if the patient is unstable.
- Notify the treating provider and the blood bank.
- Repeat the bedside check of the patient's identity, the unit label and the paperwork.
- Return the bag and tubing and send the requested blood and urine samples.

## Transfusion reactions: what to recognise and the nurse's first steps

| Reaction | Timing | Mechanism | Key sign | First nursing actions |
| --- | --- | --- | --- | --- |
| Acute hemolytic | Minutes, often within the first part of the unit | Recipient anti-A or anti-B destroy donor red cells in the vessels (type II); usually an ABO identification error | Fever, chills, back or flank pain, red or dark urine, hypotension, oozing | Stop the transfusion; keep the IV line open with normal saline; notify the provider and blood bank; recheck labels and identity; send the bag and samples |
| Febrile non-hemolytic | During or within hours | Cytokines and donor white cells in the product | Fever or chills without hemolysis | Stop; keep line open; notify; rule out hemolysis and contamination before any restart; antipyretic per order |
| Allergic (urticarial) | During the transfusion | Recipient IgE against donor plasma proteins (type I) | Hives and itching only | Stop; assess airway and breathing; notify; antihistamine per order; watch for progression |
| Anaphylactic | Seconds to minutes | Often anti-IgA antibodies in a person with IgA deficiency | Wheeze, stridor, hypotension, shock, no fever | Stop; keep line open; call for help; epinephrine per protocol; support airway and circulation |
| TRALI (lung injury) | Within 6 hours | Donor anti-HLA or anti-neutrophil antibodies activate the recipient's neutrophils in the lung | Sudden breathing distress, hypoxemia, hypotension, fever; no fluid overload | Stop; oxygen and airway support; notify the provider and blood bank |
| TACO (circulatory overload) | During or within hours | Too much volume or too fast, especially in heart failure, kidney disease, the elderly or infants | Dyspnea, hypertension, distended neck veins, crackles | Stop; sit the patient upright; oxygen; notify; diuretic per order |
| Septic | Minutes to hours | Bacteria in the unit, more often in platelets kept at room temperature | High fever, rigors, hypotension | Stop; keep line open; notify; blood cultures and send the bag for culture |
| Delayed hemolytic | Days to 2 weeks | Memory response to a red-cell antigen met in earlier transfusion or pregnancy | Falling hemoglobin, jaundice, positive direct Coombs | Report to the provider and blood bank for antibody work-up |
| Transfusion-associated GVHD | 1–2 weeks | Viable donor T cells attack an immunocompromised recipient | Rash, diarrhea, liver injury, pancytopenia | Prevented with irradiated products; report urgently |

## Memory aid

Stop, keep, call: stop the blood, keep the vein with saline, call the doctor and the blood bank.

## Test yourself

Think of the answer, then tap the question to see it.

## Fifteen minutes into a red-cell transfusion, the patient has chills, flank pain and dark urine. What does the nurse do first?

Stop the transfusion, keep the IV line open with normal saline, and notify the provider and blood bank. This picture suggests an acute hemolytic (ABO) reaction.

## How are TRALI and TACO told apart?

Both cause sudden dyspnea. TACO comes with hypertension, distended neck veins and other signs of fluid overload; TRALI is non-cardiogenic lung injury, often with hypotension and fever.

## Which patients are at risk of anaphylaxis to plasma-containing products?

People with IgA deficiency who have anti-IgA antibodies. They react to the IgA in donor plasma and may need IgA-deficient or washed products.

## What is the most common cause of a fatal acute hemolytic transfusion reaction?

An ABO mismatch from an identification error: the wrong unit given to the wrong patient. Careful bedside checks prevent it.

## How is transfusion-associated graft-versus-host disease prevented?

By irradiating cellular blood products for at-risk patients, which stops donor T cells from dividing and attacking the recipient.

[Add to my cards (5)](https://durgical.app/estudiar/?add=/en/immunology/transfusion-reactions/)

## See it in 3D

The structures of Durgical's 3D anatomy where it is found.

- [Kidneys](https://durgical.com/en/anatomy/kidney/)

## Related

- [ABO and Rh blood groups, hemolytic disease of the newborn](https://durgical.com/en/immunology/abo-and-rh-blood-groups-hemolytic-disease-of-the-newborn/)
- [Type II hypersensitivity (antibody against cells)](https://durgical.com/en/immunology/type-ii-hypersensitivity/)
- [Type I hypersensitivity (immediate, IgE)](https://durgical.com/en/immunology/type-i-hypersensitivity/)
- [Direct and indirect Coombs test](https://durgical.com/en/immunology/direct-and-indirect-coombs-test/)
- [Graft-versus-host disease](https://durgical.com/en/immunology/graft-versus-host-disease/)
- [B-cell (antibody) deficiencies: XLA, CVID, IgA deficiency, hyper-IgM](https://durgical.com/en/immunology/b-cell-deficiencies-xla-cvid-iga-deficiency-hyper-igm/)

## Related conditions

- [Transfusion reactions](https://durgical.com/en/conditions/transfusion-reactions/)
- [Anaphylaxis](https://durgical.com/en/conditions/anaphylaxis/)
- [Sickle cell disease](https://durgical.com/en/conditions/sickle-cell-disease/)
- [Thalassemias (α and β)](https://durgical.com/en/conditions/thalassemias/)

[← All of immunology](https://durgical.com/en/immunology/)

Educational content on the immune system; not a treatment or individual vaccination guide and no substitute for a health professional's advice. No doses are given.

Sources: [Transfusion Reactions](https://www.ncbi.nlm.nih.gov/books/NBK482202/) (StatPearls Publishing (NCBI Bookshelf), 2023); [ABO Blood Group System](https://www.ncbi.nlm.nih.gov/books/NBK580518/) (StatPearls Publishing (NCBI Bookshelf), 2025).

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Source: https://durgical.com/en/immunology/transfusion-reactions/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/immunology/transfusion-reactions/