Hematology, Oncology & Immunology · Topic 5 of 26

Transfusion Reactions

Hematology · transfusion complications

Transfusion Reactions

Any new symptom during a transfusion: stop it, keep the line open with saline, recheck identity and call the blood bank — assume hemolysis until proven otherwise.

Key numbers

Acute hemolysis: saline and furosemide for urine outputUO ≥ 100 mL/h

TRALI: hypoxemia, bilateral infiltrates within 6 hoursonset ≤ 6 h

Febrile nonhemolytic: temperature rise of 1 °C↑ ≥ 1 °C

01 · FirstStop the transfusion; keep saline running

For any suspected reaction, stop the transfusion, keep the line open with 0.9% saline, check vital signs, recheck patient identity against the unit label and notify the blood bank — assume hemolysis until excluded.

02 · Look forABO mismatch: fever, flank pain, shock

Acute hemolytic reaction (usually ABO incompatibility from a labeling or identification error) starts within an hour: fever, chills, flank or back pain, dyspnea, hypotension or shock, hemoglobinuria, AKI and DIC.

03 · Defined byTRALI: hypoxemia, bilateral infiltrates within 6 hours

TRALI = acute hypoxemia with bilateral infiltrates during or within 6 hours of transfusion, without left atrial hypertension; donor anti-HLA or antineutrophil antibodies cause it. Give supportive care; avoid diuretics.

Presentation

What you'll see

Febrile nonhemolytic: temperature rise of 1 °CFebrile nonhemolytic reaction, the most common, is a temperature rise of at least 1 °C (to 38 °C or more) with chills from donor leukocyte cytokines or antibodies; exclude hemolysis and sepsis, then give acetaminophen.

Under anesthesia, hemolysis shows as hypotension and oozingIn an anesthetized patient, an acute hemolytic reaction may show only as hypotension, uncontrolled bleeding from incisions and mucosa (DIC), or dark urine.

Do right now

In this order

First moves

Stop the transfusion; keep saline running

→

Send the bag and a post-transfusion sample

→

Acute hemolysis: saline and furosemide for urine outputUO ≥ 100 mL/h

Why each step

Stop the transfusion; keep saline runningFor any suspected reaction, stop the transfusion, keep the line open with 0.9% saline, check vital signs, recheck patient identity against the unit label and notify the blood bank — assume hemolysis until excluded.

Send the bag and a post-transfusion sampleReturn the unit and tubing to the blood bank and send a post-transfusion sample for repeat ABO/Rh typing and crossmatch, direct Coombs test, LDH, bilirubin, haptoglobin and urinalysis for hemoglobin.

Acute hemolysis: saline and furosemide for urine outputTreat acute hemolytic reaction with IV 0.9% saline plus furosemide 40–80 mg IV to keep urine output at least 100 mL/hour for 24 hours; consult nephrology early if no diuresis within 2–3 hours.

Management

Orders

TACO: stop the transfusion, give furosemide must knowTACO is hydrostatic edema from transfused volume, mainly in older adults or cardiac or renal disease: stop the transfusion and give IV furosemide (e.g., 20–40 mg). It is the leading cause of FDA-reported transfusion deaths.

Hives alone: antihistamine, then may resumeMild allergic reactions (urticaria, itching) are common: stop the transfusion and give an antihistamine such as diphenhydramine; if only mild urticaria and it resolves, the same unit may be resumed.

Anaphylaxis: IM epinephrine; suspect IgA deficiencyAnaphylaxis (hypotension, bronchospasm, angioedema), classically in IgA deficiency, needs epinephrine 0.3–0.5 mg IM and IV saline; do not restart. Future transfusions use washed products or IgA-deficient donors.

Septic reaction: culture patient and bag; antibioticsHigh fever, rigors and hypotension within hours — especially after room-temperature-stored platelets — suggest bacterial contamination: culture the patient and the product and start broad-spectrum antibiotics (e.g., vancomycin plus a broad beta-lactam).

Red flags & don'ts

Avoid harm

Delayed hemolysis: unexplained Hb drop 1–2 weeks later complicationDelayed hemolytic reaction is an anamnestic antibody response, usually 1–4 weeks after transfusion: unexplained fall in hemoglobin, mild fever or jaundice, raised LDH and bilirubin, and a positive direct Coombs test. Most cases are mild.

Transfusion GVHD: prevent with irradiated products complicationTransfusion-associated GVHD (donor lymphocytes attack the host) appears 4–30 days later with fever, rash, diarrhea, liver dysfunction and pancytopenia; mortality exceeds 90%, so at-risk patients get irradiated products.

TRALI or TACO?

Commonly confused

Mechanism	Permeability — donor antibodies injure the lung
Blood pressure	Hypotension
Other clues	Fever, transient leukopenia
Diuretics	Avoid — supportive care

More detail

Reference

Show 7 reference facts

Moderate allergic reactions (generalized urticaria or mild bronchospasm) add hydrocortisone 100–200 mg IV; patients with prior allergic reactions may be premedicated with diphenhydramine — drugs are never added to the blood bag.

TRALI risk rises with plasma-rich products from female donors carrying leukocyte antibodies and with a proinflammatory first hit in the recipient; TRALI is the second leading cause of transfusion death — report every case.

Post-transfusion purpura: platelets fall sharply 4–14 days after transfusion, almost always in multiparous women (anti-HPA-1a); treat with IVIG 1–2 g/kg and avoid further platelet or red-cell transfusion.

Massive transfusion adds dilutional coagulopathy, hypothermia (warm products through an in-line warmer), citrate-related hypocalcemia and potassium shifts (see Massive Transfusion & Trauma Coagulopathy).

Residual infection risk per unit in the US is about 1 in 1.5–2 million for HIV, under 1 in 2 million for hepatitis C, and about 1 in 1 million for hepatitis B.

Leukoreduced components prevent recurrent febrile reactions; acetaminophen premedication may be used before future transfusions after a febrile reaction.

Severity of an ABO-incompatible reaction depends on volume and rate: mortality rises with more than 200 mL transfused, but as little as 25 mL has been fatal.

Pearl

Fever and chills can be the first sign of an ABO mismatch — stop first, diagnose second.

Sources · Merck Manual Professional — Complications of Transfusion (rev. Apr 2026) · Ackfeld T, Schmutz T, Guechi Y, Le Terrier C. Blood Transfusion Reactions — A Comprehensive Review of the Literature including a Swiss Perspective. J Clin Med 2022;11:2859 (PMC9144124) · Vlaar APJ et al. A consensus redefinition of transfusion-related acute lung injury. Transfusion 2019;59:2465–2476 (PMC6850655) · Murphy CE, Kenny CM, Brown KF. TACO and TRALI: visualising transfusion lung injury on plain film. BMJ Case Rep 2020;13:e230426 (PMC7244285) · Klanderman RB et al. Transfusion-associated circulatory overload — a systematic review of diagnostic biomarkers. Transfusion 2019;59:795–805 (PMC7379706) · Merck Manual Professional — Anaphylaxis (epinephrine 0.3–0.5 mg IM) · US FDA CBER — Fatalities Reported to FDA Following Blood Collection and Transfusion: Annual Summary for FY2022 (TACO 34%, TRALI 18% of transfusion deaths FY2018–2022) · Starter sheet built from the verified AGACNP fact map (facts reviewed 2026-10-15).