Transfusion Reactions from Incompatible Blood: Immediate and Delayed Dangers

Receiving ABO-incompatible blood triggers a potentially fatal acute hemolytic transfusion reaction (AHTR).

Immediate Reaction (Minutes–Hours)

Recipient anti-A/B antibodies attack donor RBCs → intravascular hemolysis.

• Fever, chills, rigors
• Flank/back pain, dark urine (hemoglobinuria)
• Hypotension, tachycardia, dyspnea
• Chest pain, nausea, vomiting
• DIC, acute kidney injury, shock, death

Delayed Hemolytic Transfusion Reaction (DHTR)

Days–weeks later: anamnestic antibody response → extravascular hemolysis. Milder: falling Hb, jaundice, low-grade fever.

Complications

• Renal failure (hemoglobin casts)
• Hepatic injury
• DIC
• Severe anemia
• Death

Prevention

Strict protocols: type and screen, crossmatch, patient ID verification at bedside, electronic barcode scanning. Never assume—always verify.