H&I laboratory investigation of FNHTR includes HLA class I and II antibody testing of the patient typically by Luminex screening and SAB assays as indicated.

A febrile non haemolytic transfusion reactions (FNHTR) is defined as a 1 – 2 degree Celsius increase in temperature during or soon after a transfusion. This may be accompanied by chills and rigors. A diagnosis of FNHTR can only be made after other causes of fever such as sepsis and haemolysis have been excluded.

FNHTR can be caused by HLA antibodies in the patient binding to their cognate antigens on leucocytes in the transfused product resulting in an immune response. Leucocyte derived cytokines released into the transfused product during storage as well as cytokines released by the recipient as a result of the transfusion have also been implicated.

The incidence of HLA antibody induced FNHTR has decreased in the leucodepletion era.