Anaphylaxis is a life-threatening hypersensitivity reaction. To identify biomarkers for the condition, we assessed serum levels of apolipoprotein (Apo)A and ApoE. We found a reduction of both lipoproteins in anaphylactic mice as well as in orally challenged food allergic patients. We then compared patients after acute anaphylaxis with several control groups (nonallergic, history of allergen-triggered anaphylaxis, acute cardiovascular/febrile reactions). In this unpaired setting, ApoE levels were unaltered, while ApoA1 was reduced in the anaphylactic group. Although unable to discriminate between anaphylaxis and cardiovascular/febrile reactions, ROC curve analysis revealed a reasonably high area under the curve (AUC) of 0.91 for ApoA1. Serum 9α,11ß-PGF2 , recently identified as a suitable biomarker for anaphylaxis, outperformed ApoA1 with AUC=0.95. Intriguingly however its power further increased upon combination of both mediators reaching AUC=1. Our data suggest that ApoA1 combined with 9α,11ß-PGF2 represents a useful composite biomarker of anaphylaxis, achieving superior diagnostic power over either factor alone.