From Dysautonomia International
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On MCAS
So what tests can be done to determine if the mast cells are misbehaving? The first test that is usually done is a blood test for tryptase. Tryptase is a protein that comes from mast cells and it is usually elevated in two circumstances. The first is after a severe allergic reaction (anaphylaxis) and the second is if you have too many mast cells in your body (mastocytosis). If you have a significantly elevated tryptase, your doctor might recommend a bone marrow biopsy which is usually the definitive test for mastocytosis. Mastocytosis can be a serious illness, but it is different than the problem that most people with MCAS have. In mastocytosis, there are too many mast cells due to a genetic mutation that made one cell start to grow and divide without control. Patients with mastocytosis and MCAS are treated differently.
For most people with POTS, the tryptase level is normal and they don’t have mastocytosis. In these patients we need to look for other clues that their mast cells are not functioning normally. There are many different chemicals that come out of mast cells and can be measured. Substances like histamine, prostaglandins and leukotrienes are usually measured in a 24 hour urine sample. If the symptoms fit and the patient has evidence of making too much of a mast cell chemical, many physicians are then willing to diagnose MCAS and move on to treatment.
Although different diagnostic criteria are published, a commonly used strategy to diagnose patients is to use all three of the following:
.....................
On MCAS
So what tests can be done to determine if the mast cells are misbehaving? The first test that is usually done is a blood test for tryptase. Tryptase is a protein that comes from mast cells and it is usually elevated in two circumstances. The first is after a severe allergic reaction (anaphylaxis) and the second is if you have too many mast cells in your body (mastocytosis). If you have a significantly elevated tryptase, your doctor might recommend a bone marrow biopsy which is usually the definitive test for mastocytosis. Mastocytosis can be a serious illness, but it is different than the problem that most people with MCAS have. In mastocytosis, there are too many mast cells due to a genetic mutation that made one cell start to grow and divide without control. Patients with mastocytosis and MCAS are treated differently.
For most people with POTS, the tryptase level is normal and they don’t have mastocytosis. In these patients we need to look for other clues that their mast cells are not functioning normally. There are many different chemicals that come out of mast cells and can be measured. Substances like histamine, prostaglandins and leukotrienes are usually measured in a 24 hour urine sample. If the symptoms fit and the patient has evidence of making too much of a mast cell chemical, many physicians are then willing to diagnose MCAS and move on to treatment.
Although different diagnostic criteria are published, a commonly used strategy to diagnose patients is to use all three of the following:
- Symptoms consistent with chronic/recurrent mast cell release
a. Recurrent abdominal pain, diarrhea, flushing, itching, nasal congestion, coughing, chest tightness, wheezing, lightheadedness (usually a combination of some of these symptoms is present) - Laboratory evidence of mast cell mediator (N-methyl histamine, prostaglandin D2 or 11-beta- prostaglandin F2 alpha, leukotriene E4 and others)
- Improvement in symptoms with the use of medications that block or treat elevations in these mediators
- Read the rest of the blog here - http://www.dysautonomiainternational.org/blog/wordpress/