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Advanced Intestinal Barrier Assessment (AIBA)

Advanced Intestinal Barrier Assessment (AIBA)

Advanced Intestinal Barrier Assessment (AIBA)

About this test

The Advanced Intestinal Barrier Assessment is a useful profile to consider if you suspect you have intestinal permeability or ‘leaky gut’ and want to know what imbalances may be driving that process. This test was designed out of years of practice of integrative practitioners who recognise we can improve health by improving the gut through diet and other interventions.

This is the only profile on the market that assesses this combination of markers as possible drivers of intestinal permeability:

  • Zonulin
  • Histamine
  • Diamine Oxidase (DAO)
  • Lipopolysaccharides (LPS) IgA, IgG, IgM

Why do the AIBA Profile?

Key symptoms which suggest this profile could provide valuable clinical information include:

  • Symptoms suggestive of food intolerance
  • Symptoms suggestive of chemical hypersensitivity
  • Symptoms suggestive of elevated histamine/histamine intolerance
  • Symptoms of fatigue 
  • Eczema/frequent skin rashes/urticaria
  • Previous diagnosis/suspicions of auto-immunity
  • Altered mood/depression

What is being measured?


Zonulin is a protein that plays an important role in the opening of small intestine tight junctions. This molecule is used as a non-invasive marker of gut wall integrity. The presence of zonulin suggests an increase between the intestinal cells gap junction, causing zonulin to be secreted.  It is an early marker of disease, elevating 2-5 years in advance of autoimmune, diabetes and allergic diseases. 

Stool zonulin levels need to be shown in context of other permeability markers and current presenting symptoms. Whereas blood zonulin levels are well researched to show intestinal permeability as demonstrated in papers by the zonulin pioneer Dr Fasano. 

Diamine Oxidase (DAO)

Diamine oxidase (DAO) 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 microvilli of a healthy small intestine, certain drugs, foods, and bacteria may suppress its production.

Low levels of DAO are associated with the following symptoms and conditions:

  • Migraine, headache
  • Chronic fatigue
  • Hives, skin rash, eczema, psoriasis
  • Nasal congestion, asthma
  • Gastrointestinal disorders, inflammation, irritable bowel syndrome
  • Dysmenorrhea, PMS, estrogen dominance
  • Arrhythmia, hypertension, hypotension
  • Fibromyalgia, muscular pain
  • Rheumatoid arthritis
  • Neurological conditions such as multiple sclerosis and attention deficit and hyperactivity disorder (in childhood and adolescence)
  • Depression and anxiety


Histamine is involved in many types of allergic and inflammatory processes, including immediate and delayed hypersensitivity reactions. 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 (from certain foods), released histamine from storage sites in the body due to food or environmental triggers, or a diamine oxidase (DAO) deficiency which is 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. When suspecting food sensitivities, it can be important to also consider histamine intolerance.

High histamine levels are associated with the following symptoms and conditions:

  • Severe allergic reactions (anaphylaxis)
  • Low muscle tone
  • High blood pressure
  • Dizziness
  • Headache
  • Nausea, vomiting
  • Diarrhea, 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
    • Memory

Low histamine levels are associated with the following symptoms and conditions:

  • Fatigue
  • Depression
  • Sleep-wake disorders such as narcolepsy

DAO: Histamine Ratio

The DAO: Histamine ratio helps identify the imbalance between DAO and histamine levels. Even if DAO is reported as normal, if histamine is high, symptoms can still occur.

A low ratio can provide evidence of insufficient levels of DAO enzyme activity relative to the current level of histamine in the body.

Lipopolysaccharides (LPS) 

In humans, the presence of LPS triggers can trigger an immune response producing inflammation. 

LPS are found on the outer surfaces of some gut bacteria and when found in the blood, it means they are passing not only between intestinal cells, but also directly through the cells, potentially causing inflammation. 

Elevated levels may be associated with bacterial infection, food sensitivities, chronic inflammation, autoimmune conditions, digestive disorders, and neurological conditions.

Lipopolysaccharides (LPS) IgA, IgG, IgM

The body makes different antibodies or immunoglobulins (Ig) to protect against bacteria, viruses and allergens, including LPS.

IgM – The first immunoglobulin or antibody made when fighting a new infection is IgM; this is the early infection response. IgM clears the body more quickly than IgG.

IgG – Following that, usually around 7-14 days later you mount immunoglobulin G. The IgG response is the later response and is a longer-lasting immune response. IgG is the most common antibody and can take time to form after an infection.

IgA antibodies are found in the linings of the respiratory tract and digestive system, as well as in saliva, tears and breast milk.

If these markers are reported as high it indicates the immune system is actively fighting bacterial overload. Treatments include antimicrobials to lower the bacterial load.

Low LPS Antibodies are associated with an immune system that is chronically worn down. IBS and IBD can both be a result of an infection that was chronic and that has resulted in little to no immune reserve which can be highlighted by this test.

Type of specimen required for the test

This profile requires a fasting blood draw. 

The blood sample needs to be centrifuged.

You will need to arrange for a blood sample to be collected by a nurse at your G.P. service or at a private clinic or hospital. Any fee for this service is not included in with the test fee.


Returning your sample

You will need to send your sample back to the lab via a courier service.

Please note that samples should only be posted on Monday – Thursday so that they do not arrive over the weekend when the lab is closed.

The sample must be shipped within 24 hours of collection.

Age range this test is suitable for

There is no minimum age for this profile, however, please bear in mind that the sample requires a blood draw which may be difficult for some paediatrics.

Gram negative overgrowth can happen at any age. However, the antibody response may be muted until 5 years of age. 

Before taking this test

Patient Preparation

Antihistamines cannot be taken at least 5 days prior to this test.

Do not take steroids within one week of testing.

Do not discontinue with any medication unless supervised by your doctor

This is a fasting test. Do not consume any food for 12 hours prior to the blood draw. You may drink water. The kit will come with full instructions – please do read and follow these. 

How long does it take to get my results?

Please note: There is currently a wait of up to 2 months for results due to a worldwide shortage of one of the reagents used in the processing of the test samples. Test samples are processed as quickly as possible.

Patient Instructions

You will need to call the laboratory at least 24 hours before your blood draw appointment. Contact details will be with your test kit.

  1. Freeze the ice brick immediately, it needs at least 6 hours in the freezer. 
  2. Take the kit with you to your phlebotomy appointment.

Please find a sample Advanced Intestinal Barrier Assessment (AIBA) test report here

Smart Nutrition Advanced Intestinal Barrier function test (AIBA) Sample Report

Please note Dunwoody Labs have changed their name to Precision Point Diagnostics.