Let’s talk about MCAS — Mast Cell Activation Syndrome. The tests we have? Honestly… not that helpful. Most have low sensitivity — meaning they can miss the diagnosis even when it’s really there. Serum tryptase? Often normal in MCAS. Urine prostaglandins, leukotrienes? Only elevated if you test right after a flare and the sample is handled perfectly. Real-world sensitivity? Likely under 50%. Here’s the key: one of the diagnostic criteria for MCAS is improvement with therapy. So if your symptoms i

When I diagnose Mast Cell Activation Syndrome (MCAS), I use the Consensus 2 criteria. This method moves beyond the traditional tryptase-level criteria of Consensus 1, and focuses instead on symptom charts, response to treatment and specific lab tests. I’ve found this method to work impeccably. Many practitioners are not aware of mast cell activation syndrome and the complexity of how it can present, or either continue to use the outdated Consensus 1 approach or, worse, revert to an understanding