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DRThere was a time when I ordered mast cell testing frequently — serum tryptase, plasma histamine, 24-hour urine mediators.
Over time, I’ve stepped back.
Not because mast cell activation isn’t real — but because many of these tests lack sensitivity, fluctuate significantly, and often don’t change what I’m going to do clinically.
If someone has episodic, multi-system flares — flushing, GI symptoms, brain fog, tachycardia — especially in the context of hypermobility and dysautonomia, and I can’t otherwise explain their symptoms, I treat the mast cell physiology.
If the presentation is atypical, overlaps with autoimmune disease (lupus, inflammatory arthritis, vasculitis), or something structural, I investigate further.
But if it feels like mast cell activation, and nothing else convincingly explains it, I start there.
If they don’t respond? I reassess. I widen the lens. I reconsider testing.
Every test you order should come with an understanding of its sensitivity, specificity, and limitations. Some data points are inherently fallible. And when that’s the case, I don’t anchor to them.
Listening carefully — and watching how someone responds to thoughtful therapy — is often more informative than a single lab value.
#mcas #mastcell #mastcellactivationsyndrome #mastcellactivationdisorder #hypermobility
@drzacspiritos
