Serum or plasma mass concentration of diamine oxidase (DAO) activity
This test measures the activity level of diamine oxidase, an enzyme involved in breaking down histamine and other biogenic amines in the body. It may be used to assess conditions related to intestinal permeability or allergic responses.
["DAO activity helps diagnose conditions linked to gut lining damage or histamine intolerance."]
Key facts at a glance
- LOINC
- 11813-3
- Short code
- SB Diam US.meas
- Synonyms
- SB Diam US.meas
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- us-measured
- 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 bloating, diarrhea, or allergic reactions that could be linked to gut issues. It may also be used in research or specialized clinical settings to evaluate histamine metabolism.
What Does the Test Measure?
Diamine oxidase (DAO) is an enzyme found in the intestines and blood. It helps regulate histamine levels, a compound involved in allergic responses. Elevated or low levels may indicate problems such as increased intestinal permeability (leaky gut) or histamine intolerance.
Sample Collection and Preparation
A blood sample is typically drawn from a vein in your arm. The sample is processed into either serum (after clotting) or plasma (using an anticoagulant). The DAO activity is then measured using a specialized laboratory technique.
What Are Common Causes?
High DAO activity may be associated with conditions like intestinal inflammation, food intolerances, or certain medications. Low levels could suggest histamine intolerance or other metabolic issues, though this is less common.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical significance of DAO activity includes potential roles in diagnosing histamine-related disorders, assessing gut health, or evaluating allergic responses. Elevated levels might indicate increased intestinal permeability, while abnormal results may prompt further investigation into dietary or metabolic factors.
Short name
Diamine Oxidase Activity
Frequently asked questions
What does a high or low DAO activity level mean?
How long does it take to get results?
Is this test covered by insurance?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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 16, 2026. · Read our editorial policy