MCAS Consensus-2: Revised Criteria for Mast Cell Activation Syndrome
A peer-reviewed global consensus-2 paper led by Dr. Lawrence Afrin and co-authored by Dr. Hoffman revises MCAS diagnostic criteria, which matters for patients whose doctors know mainly systemic mastocytosis.
Dr. Bruce HoffmanMSc, MBChB, FAARM, IFMCP · Integrative medicine educator
March 4, 2024March 4, 2024Updated October 21, 20262 min read
Please take a look at this newly published peer-reviewed article by Dr. Lawrence Afrin of which I was a co-author, on the revised criteria for the diagnosis of mast cell activation syndrome (MCAS):
In one paragraph: mast cell activation syndrome is diagnosed on the basis of increased mast cell activity, not an increase in the number of mast cells, which separates it from systemic mastocytosis. Systemic mastocytosis is most often diagnosed with the biomarker tryptase, while MCAS has much broader diagnostic criteria. A peer-reviewed global consensus-2 paper by Dr. Lawrence Afrin, co-authored by Dr. Hoffman, sets out these revised criteria.
One of the most common difficulties patients seem to face after they have been to our clinic and given a diagnosis of mast cell activation syndrome is when they return to their GP’s or specialists with a description of this syndrome. Traditional medicine is well-schooled in the diagnosis of systemic mastocytosis, a condition characterized by an increased number of mast cells as opposed to MCAS which is a diagnosis arrived at due to the increased activity of mast cells (and not an increase in the actual numbers).
Systemic mastocytosis is most often diagnosed by using a biomarker called tryptase, whereas the diagnosis of MCAS has much broader diagnostic criteria as this article will outline.
For a much more in-depth description of MCAS, please see my treatment page and the following articles:
What is the difference between MCAS and systemic mastocytosis?
Systemic mastocytosis is characterised by an increased number of mast cells. MCAS is diagnosed due to increased activity of mast cells, not an increase in their actual numbers.
How is systemic mastocytosis diagnosed?
Systemic mastocytosis is most often diagnosed using a biomarker called tryptase. The diagnosis of MCAS relies on much broader diagnostic criteria.
Who wrote the global consensus-2 on MCAS diagnosis?
The peer-reviewed paper Diagnosis of mast cell activation syndrome: a global consensus-2 was written by Dr. Lawrence Afrin, with Dr. Bruce Hoffman as a co-author. It covers revised criteria for diagnosing MCAS.
Why is MCAS hard to get recognised by GPs and specialists?
Dr. Hoffman notes that traditional medicine is well-schooled in diagnosing systemic mastocytosis, a condition of increased mast cell numbers. MCAS involves increased mast cell activity and has broader criteria, so patients often struggled when describing it to their GPs or specialists.
More on MCAS & POTS
Everything Dr. Hoffman has written on mast cell activation syndrome, histamine and POTS: what it is, how it is tested, what triggers it and how it is treated, from the co-author of the global MCAS consensus-2 paper.
