Febrile non-haemolytic transfusion reactions (FNHTR)

This occurs during or within the first 24 hours of a transfusion

When to suspect this adverse reaction?

Patients present with an unexpected temperature rise (≥38ºC and ≥1ºC above baseline, if baseline ≥37ºC) during or shortly after transfusion. This is usually an isolated finding. Occasionally the fever is accompanied by chills.

Chills, rigors, increased respiratory rate, change in blood pressure, anxiety and a headache may accompany this reaction but may also occur in several more serious transfusion reactions also, the most serious being acute haemolytic reaction, transfusion transmitted bacterial infection and TRALI. FNHTR is a diagnosis of exclusion.(1,2)

This occurs in 0.1% to 1% of transfusions with leucocyte depleted products.(1)

Usual causes?

Cytokine accumulation during storage of cellular components (especially in platelet units) is thought to be the most common event leading to symptoms of FNHTRs (1). Cytokines are released by white cells and pre-storage leucodepletion has reduced this risk.(2,3)

FNHTR is also caused by the presence of recipient antibodies (2,3) (raised as a result of previous transfusions or pregnancies) reacting to donor human leucocyte antigens (HLA) or other antigens. These antigens are present on donor lymphocytes, granulocytes, or platelets.(1,2)


Clinically assess the transfused patient for fever, chills, rigors and headache.

Acute haemolytic reaction may need exclusion.

Direct antiglobulin test (DAT), blood count and repeat ABO grouping may be indicated. Consider investigations for transfusion associated sepsis.

In patients with repeated FNHTR, investigation for HLA antibodies may be useful.

What to do?

Stop transfusion immediately and follow other steps for managing suspected transfusion reactions.

Treat the fever with an antipyretic. However, avoid aspirin in thrombocytopenic and paediatric patients.

Consider and exclude other causes, as fever alone may be the first manifestation of a life threatening reaction.

Rule out acute haemolytic reactiontransfusion associated sepsis and Transfusion-related acute lung injury (TRALI).

Recommencement of the transfusion, at a slow rate, is possible if other causes of a fever have been excluded.

  1. Fung MK (ed). Non-infectious complications of blood transfusion. Chapter 27, AABB Technical Manual, 18th edition. AABB, Bethesda, 2014.
  2. Popovsky M (ed). Transfusion reactions, 3rd edition. AABB Press, Bethesda, 2007.
  3. Callum JL, Lin Y, Pinkerton PH, Karkouti K, Pendergrast JM, Robitaile N et al. Chapter 5, Transfusion Reactions. Bloody Easy 3: Blood Transfusions, Blood Alternatives and Transfusion Reactions: A Guide to Transfusion Medicine, 3rd edition. Canada: Ontario Regional Blood Coordinating Network, 2011. [cited 2012 Sep 13]. Available from: transfusionontario.org/en/documents/?cat=bloody_easy