Some science behind the scenes

Stool test

 

A stool test involves the collection and analysis of fecal matter.  Its most common regular use is in the ‘fecal occult blood test’, which can be used to identify whether there is any blood in the stool, which may have been caused by bleeding in the gastrointestinal system, itself a symptom of colorectal cancer or stomach cancer.  It is worth noting that “Participants at higher age have a significantly higher risk of a false negative result. Males were at increased risk of a false positive result, so were smokers and regular NSAID users”.  So it is indicative, not a final test.

  • Parasitic diseases such as ascariasis, hookworm, strongyloidiasis and whipworm can be diagnosed by examining stools under a microscope for the presence of worm larvae or eggs.
  • Some bacterial diseases can be detected with a stool culture. Toxins from bacteria such as Clostridium difficile ('C. diff.') can also be identified.
  • Viruses such as rotavirus can also be found in stools.

Biomarkers

There is also the possibility to look for so called biomarkers.  For example, testing a stool culture for beneficial bacteria (Lactobacillus and Bifidobacterium) may provide evidence of low growth suggestive of intestinal dysbiosis.  If the stool has abnormally elevated eosinophil protein X, this is suggestive of a food allergy.  Elevated calprotectin is suggestive of inflammation.  Low pancreatic elastase is suggestive of exocrine pancreatic insufficiency.

There are other inflammation markers that can signify that not all is well with the intestine.  With food allergies, increased IgE and histamine levels may be present  in the stool itself.  If only histamine levels are elevated, the view appears to be that this can be classified as an intolerance, for example a lactose intolerance.

Steatorrhea can be diagnosed using a Fecal fat test that checks for the malabsorption of fat.

Key biomarkers

The following are key biomarkers

  • Alpha-1-antitrypsin is an enzyme formed in the liver and found in the intestine if the permeability of the intestinal mucosa has been increased.
    This is a key test, as when this is the case large molecules can penetrate these mucous membranes and arrive in the blood and we have all the makings of an allergy.  This applies especially to the biogenous amines contained within foods and to many 'pseudo'allergenic' substances.
    With increasing intolerance to foods in general, there is increasing gluten and sugar intolerance.
    People with rheumatoid arthritis and also with eczema of long standing should really have this test.
  • Lysozyme - Lysozyme is formed by macrophages and granulocytes.  If the mucous membrane barrier is no longer intact because of inflammation then the value is increased.  
  • PMN elastase - originates from polymorphonuclear granulocytes, which are responsible for the removal of foreign proteins or denatured body proteins.  With any inflammatin PMN elastase is formed
  • Pancreas elastase - gives reliable information abut the pancreatic function.  The pancreas is an organ where environmental poisons and residual viral and bacterial burdens end up and become concentrated.  Quite frequently an otherwise fine intestinal result may hide a pancreatic abnormality