A patient with a fever associated with the transfusion of a blood product needs to be evaluated in order to determine the cause. Some causes are significant while others are not.


When transfusing multiple blood products, it is important to evaluate the patient’s temperatures:

(1) before and after each product being transfused

(2) before the first and after the last product


A febrile reaction is usually defined as a rise in temperature by >= 1°C (>= 1.8 °F) from the pretransfusion level.


Questions that should be asked when evaluating the patient:

(1) Was the rise in temperature temporally related to a blood product transfusion?

(2) Was the onset of fever immediate, acute or delayed relative to the start of the transfusion?

(3) What type of blood product was implicated?

(4) Was there concurrent hemolysis?

(5) What comorbid conditions does the patient have?

(6) What medications is the patient receiving?

(7) Does the patient have history of a febrile reaction in the past?

(8) Was the blood product leuko-poor or leuko-reduced?

(9) Was the patient pretreated prior to the transfusion? If so, with what?

(10) Was the blood product irradiated?

(11) Were blood cells transfused that were recovered during surgery?


Causes of a pseudo-febrile reaction:

(1) resuscitation from hypothermia to normothermia

(2) concurrent infection

(3) febrile reaction to a drug

(4) early postoperative period, especially after orthopedic surgery

(5) error in temperature measurement or recording


Immediate febrile reactions may include:

(1) bacterial contamination and overgrowth in the product

(2) severe hemolytic transfusion reaction to incompatible blood

(3) allergic reaction with anaphylaxis


Acute febrile reactions may include:

(1) acute hemolytic transfusion reaction to incompatible blood

(2) reactivation of an infection (bacterial, malaria)

(3) nonhemolytic reaction to leukocyte antigens

(4) nonhemolytic reaction to platelet or protein antigens


Delayed febrile reactions may include:

(1) delayed hemolytic transfusion reaction

(2) graft-vs-host disease (GVHD)

(3) serum sickness

(4) hyperhemolysis in sickle cell disease

(5) virus transmitted by the product

(6) bacteria transmitted by the product

(7) parasite transmitted by the product


To read more or access our algorithms and calculators, please log in or register.