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Serum Mast Cell Trypsin-Like Protein (MCTP) Level

Published: August 9, 2026Updated: August 17, 2026

This test measures a protein produced by mast cells, which are immune cells involved in allergic reactions and inflammation. It helps assess mast cell activity and may indicate conditions like mastocytosis or allergic disorders.

Quick summary

["This test helps evaluate mast cell function and potential underlying health concerns."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
26141-2
Short code
XR Mastoid-R Views
Synonyms
XR Mastoid-R Views
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 500 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
xr
CPT
84484
SNOMED
302774002
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order this test if you have symptoms like chronic hives, digestive issues, or unexplained allergic reactions. It may also be used to monitor conditions like mastocytosis or to check for abnormal mast cell activity in certain blood disorders.

What to Expect Before the Test

No special preparation is usually needed. You may have a simple blood draw, similar to other routine blood tests. If you’re on blood thinners or have a history of bleeding disorders, let your provider know.

What the Test Results Mean

Results may not have a single reference range since levels can vary based on health conditions and activity. Elevated levels might suggest increased mast cell activity, while lower levels could indicate reduced activity. Your provider will interpret results in the context of your symptoms and medical history.

Common Conditions This Test Helps Diagnose

This test is often used to support a diagnosis of mastocytosis (a rare blood disorder where mast cells multiply abnormally) or to investigate symptoms linked to mast cell dysfunction, such as chronic urticaria (hives) or gastrointestinal issues.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Mast Cell Trypsin-Like Protein

Frequently asked questions

What causes elevated or low levels of this protein?
Elevated levels may be linked to conditions like mastocytosis, allergic reactions, or certain inflammatory diseases. Low levels could suggest reduced mast cell function or activity, though this is less common. Your provider will consider other factors, like your symptoms and medical history, when evaluating results.
How often should I get this test?
The frequency depends on your health condition and treatment plan. If you have mastocytosis or another related disorder, your provider may recommend regular monitoring. Otherwise, this test is usually done as needed for specific symptoms or investigations.
Does this test interact with any medications?
There are no widely known interactions with common medications, but your provider should be aware of any prescriptions or supplements you take. Some blood thinners or medications that affect immune function may indirectly influence results, so it’s important to discuss your full medication list.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy