Pathophysiology & Risk Factors

An acute hemolytic transfusion reaction (AHTR) occurs when ABO-incompatible blood triggers rapid intravascular destruction of donor red cells, releasing free hemoglobin and activating the complement cascade. It typically begins within the first 15 minutes of infusion, sometimes after only 10-15 mL. Clerical misidentification at the bedside is the leading cause. Delayed hemolytic reactions are extravascular and present 2-14 days later with a gradual hemoglobin drop, mild jaundice, and low-grade fever.

Signs & Symptoms

EarlyProgresses →

IV-site burning

early subjective cue

sense of impending doom

chest tightness

fever with chills Hallmark

rise greater than or equal to 1 degree C is significant

flank or low back pain Hallmark

dark cola-colored urine Hallmark

hemoglobinuria

tachycardia

Late / Severe

hypotension

oozing from IV sites

DIC onset

Diagnostics & Labs

Diagnostic

positive direct Coombs test

may be negative in AHTR if donor cells destroyed

hemoglobinuria

free hemoglobin in urine

decreased haptoglobin

elevated indirect bilirubin

elevated LDH

Monitor

urine outputmaintain greater than 30 mL/hr

Interventions & Priorities

AHTR response sequence

STOP the transfusionclamp tubing at port closest to client
Disconnect blood tubingkeep IV catheter in place
Hang new NS with new tubingnever flush old tubing
Full vital signs + notify provider and blood bank
Send bag and tubing to blood bankfresh sample from opposite arm to lab
Aggressive IV NS + monitor urine outputflush kidneys, support BP

Patient Teaching

verify identity with two identifiers

active self-identification at bedside

two-nurse blood verification

ABO, unit number, expiration

start infusion slowly first 15 minutes

limits volume if reaction occurs

report burning or back pain immediately

stay with client during first 15 minutes

Complications

acute kidney injury

most dangerous complication; hemoglobin precipitation in tubules

disseminated intravascular coagulation

circulatory shock

Report Nowescalate immediately

stop the transfusion at first suspicion Hallmark

every additional mL worsens hemolysis

flank pain with hemoglobinuria

intravascular hemolysis

hypotension with tachycardia

systemic inflammatory response

urine output below 30 mL/hrless than 30 mL/hr

hemoglobin-induced AKI

oozing from IV sites

DIC onset

Clinical Pearl

Recognition: back pain + dark urine + fever during a transfusion = hemolytic until proven otherwise. Response: Stop, swap, save - stop the blood, swap to new NS with new tubing, save the bag for the blood bank.