| Level 1, 2 & 3 | Must meet both of the following criteria (if one or both not met, it is not a case–level 5):___Sudden onset of symptoms/signs___Rapid progression of symptoms/signs |
| Use the pattern of MAJOR and minor criteria met for skin, respiratory, cardiac and gastrointestinal (GI) systems and laboratory result from the table above to determine the highest level of diagnostic certainty (with level 1>level 2>level 3) |
| Level 1 | ≥1 Skin MAJOR AND (≥1 Respiratory MAJOR AND/OR≥1 Cardiac MAJOR) |
| Level 2 (4 different ways to meet level 2) | 1. ≥1 Skin MAJOR AND (≥1 Respiratory minor AND/OR≥1 Cardiac minor)2. ≥1 Respiratory MAJOR AND≥1 Cardiac MAJOR3. ≥1 Respiratory MAJOR AND≥1 minor from a different system (Skin, Cardiac, GI, lab)4. ≥1 Cardiac MAJOR AND≥1 minor from a different system (Skin, Respiratory, GI, lab) |
| Level 3 (2 different ways to meet level 3) | 1. ≥1 Respiratory minor AND≥1 minor from each of 2 different systems (Skin, Cardiac, GI, lab)2. ≥1 Cardiac minor AND≥1 minor from each of 2 different system (Skin, Respiratory, GI, lab) |
| Level 4 | Reported anaphylaxis with insufficient evidence to meet any of levels of diagnostic certainty |
| Level 5 | Not a case of anaphylaxis: if unable to check 1.1 and 1.2 (i.e., onset not sudden and did not progress rapidly) |