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What are the lab tests used to help detect MCAS?

Peyt

Senior Member
Messages
678
Location
Southern California
Methyl-histamine, Prostaglandins (PG D2 and PG F2 Alpha), Tryptase, and many others. Some test are blood and others are urine. The blog/website "Mast Attack" lists all of them and is a very good resource.
Do people with this condition generally have higher than normal histamine?
The reason I ask is I actually was tested for histamine and my histamine is lower than normal. but
the symptoms are close to what I have been suffering with.
 

Gingergrrl

Senior Member
Messages
16,171
Do people with this condition generally have higher than normal histamine? The reason I ask is I actually was tested for histamine and my histamine is lower than normal. but the symptoms are close to what I have been suffering with.

My understanding is that there is great variation in symptoms and test results amongst patients with MCAS. At present, I remain in remission with no allergic reactions to food or smells yet my PG F2 Alpha test is in the thousands (and upper cut-off is around 200). My initial histamine test in Dec 2014 was 4x the normal limit but I did not develop acute symptoms until three months later. And there was yet another point that my tests had normalized with MCAS meds but my symptoms were still off the charts. So I have not found that test results always correlated with symptoms in my own case.
 

Research 1st

Severe ME, POTS & MCAS.
Messages
768
Don't want to sound like a party pooper here guys, but it's largely pointless running histamine/tryptase unless you test it rapidly as in you need to have an attack in the hospital (supervised) or in the ER within 60 mins.

This is why it's hard to diagnose using 'accepted' general assays hospital use for more accepted conditions, because naturally few patients can have an 'agreement' that you turn up at 3.12am in your local emergency department in a MCAS episode and there's a kind lab team sitting waiting ready to process your sample just in case you turn up. Sure if you were dangerously ill and getting swelling they can't not believe you, but less obvious symptoms are less believed. (Dizzyness, SOB, pain).

It's so infuriating to be allergic to so many things, and just have allergic attacks out of nowhere (in bed) that is like being in a loft full of dust or worse, but not having and 'evidence' to show a doctor of what happens during these attacks to explain why you're flying around the room on vertigo, getting migraines, panic, nausea, terrible burning pain, asthma, watering eyes, itching, low BP, high BP, or far worse... maybe infuriating isn't the word, scary and dangerous is more accurate to be honest when this happens for years and no one cares to have you in hospital for observation, or lets you, on agreement you don't trigger MCAS.

Catch 22. I've had this before with meds. They claim you aren't allergic and putting it on, so you offer to come to hospital and take the drug that made you really sick and they say no, that's not safe because you might be allergic!
 

Gingergrrl

Senior Member
Messages
16,171
Don't want to sound like a party pooper here guys, but it's largely pointless running histamine/tryptase unless you test it rapidly as in you need to have an attack in the hospital (supervised) or in the ER within 60 mins.

This was not my experience and I think there must be great variation amongst patients. My first test was at OMI as part of routine blood testing (in 2014) and we were stunned when it showed blood histamine at 4x the normal limit b/c it was three months before I had my first allergic reaction to a yellow food dye.

Now I've been in remission (to the MCAS part of my illness, not to everything!) for 10 mos from IVIG so we tested prostaglandin levels on a random date (right before my IVIG at infusion center in March 2017) expecting them to be normal but both were elevated. One (PG D2) was only about 20 points above the upper range but the PG F2 Alpha was in the thousands and upper range about 200. We were very surprised b/c am no longer having allergic reactions to food or smells.

For me the numbers do not correlate with the symptoms b/c my tests before I started IVIG (when I was still quite symptomatic and taking 7-8 MCAS meds just to eat food) were all on the high end of "normal".
 

Gingergrrl

Senior Member
Messages
16,171

justy

Donate Advocate Demonstrate
Messages
5,524
Location
U.K
While tests are available that may point to an MCAS diagnosis they are not necessarily conclusive, Many people with MCAS show no elevated markers, some only show elevated when in a reaction, and then there is the issue of labs not knowing how to handle and store samples correctly.

A good Dr with knowledge of MCAS would diagnose clinically not just based on test results. For a full discussion of MCAS I suggest Dr Afrin's excellent book Never Bet Against Occam.
 

redo

Senior Member
Messages
874
I see Wikipedia lists this as useful when making a MCAS diagnosis:
Laboratory evidence of mast cell mediator (elevated serum tryptase, N-methyl histamine, prostaglandin D2 or 11-beta- prostaglandin F2 alpha, leukotriene E4 and others)

But, where's the best place to get tested for it? If there is a reputable lab that any doctor would accept the results from, then that's best - naturally.
 

Neunistiva

Senior Member
Messages
442
The Mastocytosis Society (TMS) said:
Consensus members also agreed that when serum tryptase evaluation is not available or when the tryptase level does not rise sufficiently to meet the required increase for the co-criterion, other mediator tests could suffice. A rise in urinary n-methyl histamine, prostaglandin-D2, or its metabolite, 11β-prostaglandin-F2α (24-hour urine test for any of the three), is considered an alternative for the co-criterion related to a requirement for a mast cell mediator level rise during a systemic mast cell activation event.
...
Mastocytosis Society said:
TMS does recognize, however, that capturing a mediator rise is not always easy, and depends on many factors, internal and environmental. We have seen 24-hour urine samples test negative simply because the lab technician did not refrigerate the sample in a timely manner (when the test was repeated and handled properly, the result was positive). Therefore, we support the use of a clinical diagnosis and advise that the patient continues to be treated when the following criteria have been met:7

  • An exhaustive work-up has ruled out other medical conditions with similar symptoms and presentations
  • The patient has exhibited consistent symptoms of mast cell activation in 2 or more organ systems during the same period of time, such as skin, gastrointestinal tract, central nervous system, etc.
  • The patient responds to antimediator therapy
  • The patient is monitored on a regular basis, with testing for mediator rises performed periodically, by a mast cell or other specialist and/or in conjunction with an established local allergist or other physician
  • The patient is evaluated for other disease processes on an ongoing basis in order to be inclusive of any new changes in the patient’s condition

https://tmsforacure.org/tests/

I would also like to get checked but have no idea how since I'm not in the US.
 
Messages
23
Location
New Mexico
Dear @Neunistiva and @redo,
Even Afrin, the "godfather" of MCAS knowledge does not have a magic laboratory to send anyone to. The problem is after the blood draw or submitting the 24-hour urine, ANYONE in the chain of taking the sample to testing it can very easily screw this up. The half-life of many mast cell mediators tested is ONE MINUTE, meaning, if they leave it unrefrigerated for even a miniscule amount of time, the amount of histamine/heparin/prostaglandin D2, etc. are reduced by HALF, then in the second minute, in HALF again! Also ones release of mediators goes up and down a lot. Kind of a mess, in terms of testing, huh!
 

Gingergrrl

Senior Member
Messages
16,171
Even Afrin, the "godfather" of MCAS knowledge does not have a magic laboratory to send anyone to. The problem is after the blood draw or submitting the 24-hour urine, ANYONE in the chain of taking the sample to testing it can very easily screw this up. The half-life of many mast cell mediators tested is ONE MINUTE, meaning, if they leave it unrefrigerated for even a miniscule amount of time, the amount of histamine/heparin/prostaglandin D2, etc. are reduced by HALF, then in the second minute, in HALF again! Also ones release of mediators goes up and down a lot. Kind of a mess, in terms of testing, huh!

My own situation was so weird b/c in Dec 2014 my main doctor tested me for MCAS markers and my blood histamine was 4x the normal limit. I had no allergic symptoms (yet) and we were both shocked at the results. He wanted to put me on H1 and H2 blockers immediately but I declined b/c I thought I did not need them.

By March 2015, I started having allergic reactions to yellow and red food dyes and by April/May, I was allergic to all food but water and ended up in the hospital for a week. It was crazy that the tests picked up on it before my anaphylactic reactions started. My doctor said this is very unusual but pretty much everything about my case has been unusual.