Version August 2025
| Test | Comment |
| Plasma-free metanephrine Urinary vanillylmandelic acid | Elevated in pheochromocytoma, not systemic anaphylaxis |
| Serum serotonin Urinary 5-hydroxyindoleacetic acid | Elevated in carcinoid syndrome, not systemic anaphylaxis |
| Serum vasointestinal polypeptide hormone panel: Pancreastatin, vasoactive intestinal peptide, substance P, neurokinin | To rule out gastrointestinal tumors or medullary carcinoma of the thyroid, which can secrete these vasoactive mediators |
| Plasma kallikrein High-molecular-weight kininogen | To assess activation of the contact pathway, leading to production of bradykinin |
| Plasma C3a or C5a | To assess activation of the complement pathway, leading to production of these anaphylatoxins |
