Test | Comment | Availability |
Total tryptase (serum/plasma) | Mature + proforms of alpha/beta tryptases. Maximal elevation above baseline 30 to 120 minutes after onset of anaphylaxis. Declines to baseline with a half-life of approximately 2 hours. Comparing acute and baseline levels improves sensitivity and specificity. | Thermo Fisher Scientific (many commercial laboratories) |
Histamine (plasma) | Peaks 5 to 10 minutes after symptom onset and declines to baseline by 15 to 30 minutes. Histamine may be released ex vivo by passing basophils in blood through a small-bore needle under vacuum or when blood clots. | Most commercial laboratories |
Histamine (24-hour urine) | May be elevated in urine collected up to 24 hours after symptom onset, but histamine-containing foods and histamine-producing mucosal bacteria may be problematic sources. | Most commercial laboratories |
N-methylhistamine (24-hour urine) | Most commercial laboratories | |
N-methylimidazole acetic acid (24-hour urine) | Research laboratories | |
11-beta-prostaglandin F2-alpha (24-hour urine) | Prostaglandin D2 metabolite; falsely low if cyclooxygenase inhibitor taken; produced by activated mast cells, eosinophils, antigen-presenting cells, megakaryocytes, and T helper type 2 lymphocytes but not by basophils. | Some commercial laboratories (Mayo Clinic) |
Leukotriene E4 (24-hour urine) | Leukotriene C4 metabolite; produced by mast cells, basophils, eosinophils, certain phagocytic mononuclear cells, endothelial cells, vascular smooth muscle cells, and platelets. | Some commercial laboratories (Mayo Clinic) |
Platelet-activating factor (plasma) | May be useful for food-induced anaphylaxis; human cell source(s) uncertain. | Research laboratories |
Do you want to add Medilib to your home screen?