Introduction: Disturbances of the gut barrier function

have been related to a variety of diseases, including intestinal

and extra-intestinal diseases. The intestinal permeability

tests are considered useful tools for evaluating

disease severity and to follow-up patients after a therapeutic

intervention and indirectly assess barrier function.

Objective: The aims of this review were to highlight the

possible factors underlying higher intestinal permeability

and the clinical conditions that have been associated with

this in different age range; and also provide some insight

into methodological aspects.

Results and discussion: Abnormal regulation of tight

junction function is the main cause of altered intestinal

barrier. The impaired barrier function results in higher

permeation rates of administered probes through the

intestinal mucosa. Lactulose and mannitol are one of the

most commonly used probes. The innocuousness and

easiness of intestinal permeability tests can be explored to

expand the knowledge about the clinical situations in

which intestinal barrier dysfunction can be an important

feature. Many factors may influence the results of the

test. Researchers and healthcare professionals should try

to circumvent the possible pitfalls of the intestinal permeability

tests to produce consistent evidences. The use of

others markers of intestinal physiology may also contribute

to understand the role of barrier function in different

diseases.