The results of the tryptase blood test are used to indicate whether mast cell activation has taken place. These cells are tissue cells that are found in bone marrow, the intestines, skin, and even in airways. The cells release tryptase when an injury occurs, but is more commonly present when there is an allergic reaction of some kind.
This is a rare blood test to be ordered. It is used to examine two specific health situations: whether anaphylaxis shock from an allergic reaction has occurred or if mastocytosis has occurred. Most people who are having an anaphylaxis reaction can be sight diagnosed and treatment, which means the primary reason why this blood test is ordered is for anaphylaxis-like symptoms that may not be allergy related.
These recurrent and chronic symptoms that do not have an explanation may cause a medical provider to order the tryptase blood test.
1. Flushing of the skin, low blood pressure, or swelling in the face.
2. Nausea, vomiting, stomach pain, or changes in bowel movements.
3. Dizziness, lightheadedness, or cardiac arrhythmia.
4. Confusion, itching, difficulty breathing or a loss of consciousness.
Symptoms may appear in any combination and in any level of severity.
What Do My Test Results Mean?
Most people who have the tryptase blood test will have results that come back as normal. This indicates that the mast cells are not activating to cause the symptoms that are being felt. It may also be an indication that the sampling of the blood test fell outside of the peak time of high tryptase levels. When a severe allergic reaction occurs, tryptaste will usually peak within 2 hours of symptom onset. Early or late samples will still come back as normal.
Sometimes the tryptase blood test is combined with a histamine test to determine if an allergic reaction has occurred. If one test is normal while the other is abnormal, then this may suggest that there is an allergy which needs to be treated. If both are negative, then there may another medical issue going on.
As for mastocytosis, a positive test result must be present with the symptoms of mast cell activation without the presence of an allergy. This result will typically require additional blood tests to corroborate the results that have been received. Because it is such a rare condition, the assumption of any result over 10 with anaphylaxis symptoms is typically treated as an allergic reaction.
Acute elevation of tryptase is typically a result of a severe allergic reaction and is typically treated as such.
This Is Not an Allergy Test
The tryptase blood test is not used to determine if there is a specific allergy present. A medical provider will order allergy tests to determine what substances may be causing a reaction. This blood test is only ordered to determine if a potentially rapidly fatal reaction is occurring because of a severe reaction to an allergy.
What Do My Numbers Mean?
Many test results for the tryptase blood test are communicated as “normal” or “abnormal” or “high.” Some medical providers, however, may provide the actual numbers of the test instead. These are the numbers that are given to them from the laboratory and indicate what a person’s total tryptase levels happen to be. It includes all forms together and then compares mature tryptase ratios to the total amount.
This provides a test result that is called the “total to mature rate.” It may also be called the TMR. If someone has a TMR that is 10 or below, then this is an indication that anaphylaxis has occurred. If the TMR is above 20, however, this may be an indication of systemic mastocytosis. Results that are 11-19 typically require follow-up testing to determine what may be happening.
If the tryptase blood test results indicate that the TMR is above 20, the medical provider will typically order a bone marrow aspiration. This is used to confirm the diagnosis. It is necessary because there are some individuals who have an allergic reaction that causes a high total to mature rate.
In rare cases, there may be a genetic mutation to blame for these high results. Specific testing for this issue is often the last test conducted if all other tests ordered are unable to determine a definitive diagnosis.
The tryptase blood test results explained here can be a guide to help you speak with your medical provider. This uncommon blood test can help to determine if an allergy or something potentially more systemic and serious has occurred to cause bothersome physical symptoms.