Laboratory Diagnostics

Please log in to buy

Advanced Intestinal Barrier Assessment


Measured Biomarkers:

  • Zonulin is a protein that regulates tight gap junctions in the gastrointestinal tract and modulates intestinal permeability
  • Diamine oxidase (DAO) is an enzyme that breaks down histamine.
  • Histamine is a compound that affects immune response, physiological function of the digestive tract, and acts as a neurotransmitter.
  • LPS is a bacterial endotoxin that increases with transcellular permeability of the gastrointestinal lining (leaky gut).
  • Why test Zonulin?

    Zonulin plays an important role in the opening of small intestine tight junctions. The loss of gut wall integrity during conditions such sepsis might be pivotal and has been described in various experimental involving human studies. As mentioned previously, increased levels of zonulin could also be demonstrated in diseases associated with increased intestinal inflammation, such as celiac disease and type 1 diabetes. Therefore we measure this molecule as a non-invasive marker of gut wall integrity

    Why Test for DAO?

    Diamine oxidase is the body’s primary enzyme for breaking down ingested histamine and a natural defence against histamine excess. If you ingest too much dietary histamine or produce more than your DAO level can handle, reactions can occur. DAO is produced in the small intestine but certain drugs, foods and bacteria may suppress its production.

    Why Test Histamine?


    Histamine is involved in many types of allergic and inflammatory processes, including immediate and delayed hypersensitivity reactions. It also acts as a neurotransmitter and regulates physiological function in the gastrointestinal tract. Histamine imbalances in the body may cause a variety of adverse effects ranging from life-threatening allergic reactions to localised itching, runny nose or hives. 

    An excess of histamine may be a result of ingested histamine (certain foods), released histamine from storage sites in the body (from food or environmental triggers), or a diamine oxidase deficiency (needed for the breakdown of histamine). Testing histamine along with diamine oxidase (DAO) levels provides important information that standard food sensitivity tests may not reveal. In fact, many clinicians often suspect food sensitivities when the culprit may actually be histamine intolerance. An excellent full text review of histamine intolerance is available. 

    Why test LPS?

    An elevated lipopolysaccharide (LPS) level indicates intestinal permeability or “leaky gut.” Lipopolysaccharide is the immunogenic portion, as well as the major constituent, of the outer cell membrane of gram-negative bacteria. LPS is a bacterial endotoxin made by bacteria in the body. When lipopolysaccharides are high in the blood, it means they are passing not only between intestinal cells, but also directly through the cells, potentially causing neuroinflammation and brain injury. When LPS is absorbed into systemic circulation it can elicit a strong immune response.

    Sample Type
    Plasma (requires phlebotomy service)
    Turnaround time
    15 working days
    Additional Information / Instructions

    Clinical signs and symptoms that may indicate a need for testing:

    Low DAO levels:

    • Migraine, headache
    • Chronic fatigue
    • Hives, skin rash, eczema, psoriasis
    • Nasal congestion, asthma
    • Gastrointestinal disorders, inflammation, irritable bowel syndrome
    • Dysmenorrhea, PMS, oestrogen dominance
    • Arrhythmia, hypertension, hypotension
    • Fibromyalgia, muscular pain
    • Rheumatoid arthritis
    • Neurological conditions such as multiple sclerosis and ADHD
    • Depression and anxiety


    High histamine levels:

    • Severe allergic reactions (anaphylaxis)
    • Low muscle tone
    • High blood pressure
    • Dizziness
    • Headache
    • Nausea, vomiting
    • Diarrhoea, gas
    • Intestinal cramps
    • Painful menstruation
    • Shortness of breath
    • Congestion, runny nose, sneezing
    • Hives, itching, flushing
    • Abnormal heart rate
    • Changes in Circadian rhythm, Body temperature, Food intake, Learning

    Elevated LPS:

    • Bacterial infection
    • Food sensitivities
    • Chronic inflammation
    • Autoimmune conditions
    • Digestive disorders
    • Neurological conditions.



    Sample Reports / Downloads