06 March 2022
: Case report 
The Missing Link: A Case of Severe Adverse Reaction to Histamine in Food and Beverages
Unknown etiology, Challenging differential diagnosis
József Tamasi1ABDEF*, Zsuzsanna Balla2BDE, Dorottya Csuka2BD, László Kalabay1DE, Henriette Farkas2BDEDOI: 10.12659/AJCR.934212
Am J Case Rep 2022; 23:e934212
Table 3. Relevant laboratory tests in case of an adverse reaction to histamine found in food and beverages.
| Test | Value | Normal range |
|---|---|---|
| Inter-attack tryptase levels | 4.8 µg/L, 6.3 µg/L | Under 11.4 µg/L |
| Plasma histamine levels | 3.3 nmol/L, 7 nmol/L | Under 9 nmol/L |
| Serum DAO concentration ELISA | 24.9 U/mL | 10–100 U/mL |
| Serum DAO activity | 12.5 IU/mL | 14–33 IU/mL |
| Total Cu levels | 13 µmol/L | 10–22 μmol/L |
| Pyridoxal-5-phospate (active form of vitamin B6) | 53.9 ng/mL | 14.5–45 ng/mL |