From the Guidelines

Febrile non-hemolytic transfusion reaction is estimated to occur in approximately 1.1% to 2.15% of transfusions.

The risk of febrile non-hemolytic transfusion reactions is influenced by the method of leukoreduction, with prestorage leukoreduction resulting in a lower risk of 1.1% compared to poststorage leukoreduction, which has a risk of 2.15% 1.
This type of reaction is a common complication of blood transfusions, and its incidence is higher than that of more severe reactions such as transfusion-related acute lung injury (TRALI) or transfusion-associated circulatory overload (TACO).

In comparison, the risk of fatal hemolysis is estimated to be 1:1,250,000 or 8 per 10 million red blood cell units transfused 1.
The risk of life-threatening transfusion reactions requiring major medical intervention is 1:139,908 transfusions or 7.1 per million transfusions 1.

Clinicians should be aware of the risk of febrile non-hemolytic transfusion reactions and monitor patients closely during and after transfusions.
The use of prestorage leukoreduction may help reduce the risk of this type of reaction 1.

From the Research

Febrile non-hemolytic transfusion reaction (FNHTR) is a type of transfusion reaction characterized by a post-transfusion temperature rise or chills/rigors unrelated to the underlying condition 2.
The pathophysiological mechanisms of FNHTR mainly include immune and non-immune pathways, with the former associated with antibodies against human leukocyte antigen (HLA) and the latter with cytokines released from blood products during storage 2.

Women with a reproductive history and patients with multiple blood transfusions are more likely to experience FNHTR 2.
Primary hematologic disease, malignant disease, and transfusion with over 6 units of leukocyte-depleted packed red blood cells are independent risk factors for the development of FNHTR 2.

FNHTR can be diagnosed by the accompaniment of fever symptoms (body temperature ≥38 ℃, or an increase of body temperature of more than 1 ℃ compared with that before blood transfusion) during or within 4 hours after transfusion, or the presence of chills, shakes, headache, and nausea, among other symptoms 2.
FNHTR should be mainly differentiated from other types of transfusion reactions with similar symptoms 2.

Removal of leukocyte components from blood can reduce the incidence of FNHTR significantly 3, 2.
Prophylactic strategies for the routine use of antipyretic drugs before transfusion remain controversial 4, 2.
Treatment for FNHTR is currently limited to antipyretic drugs, sedation, and other symptomatic treatment measures 2.

FNHTRs are among the most commonly reported transfusion disturbances, with an overall per-product rate of 0.24% 5.
The impact of FNHTRs on patients and hospitals may be underestimated, with a substantial burden of post-reaction clinical activity in addition to the disturbance itself 5.
Efforts to avoid this adverse event may save resources, reduce patient distress, and encourage compliance with more restrictive transfusion strategies 5.