In vitro hemolysis occurring before or after a blood transfusion may mimic an in vivo hemolytic transfusion reaction.
Before or During Infusion
Blood Sample Handling
environmental or unregulated refrigerator
environmental, specimen handling, or unregulated refrigerator
blood warmer or makeshift warmer; placing blood on a room heater
mixing with hypotonic or hypertonic solution
infusion of blood with an IV solution; addition of a drug
drawing from a peripheral line running an infusion
small needle with high pressure
use of pressure bag forcing flow through small needle
difficult draw with large syringe
Some causes of in vitro hemolysis:
(1) storing blood in an unregulated refrigerator, with undetected freezing
(2) using a microwave oven or other unregulated device to warm blood
(3) malfunction of a blood warmer
(4) traveling in an ambulance or helicopter during the winter
Both occurrences require a high index of suspicion, usually after the transfusion reaction workup turns up negative:
(1) A careful redraw of a new sample will usually detect a problem in specimen handling.
(2) Preinfusion hemolysis often requires exclusion of the different causes plus circumstantial evidence.
(2a) If the blood bag or infusion setup is still available then it should be examined.
(2b) If a blood warmer was used it should be tested.
(2c) All personnel involved in handling and transfusing the implicated blood product(s) should be debriefed.
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Specialty: Clinical Laboratory