Functional lab tests help show the root cause of digestive symptoms. These are non-invasive tests that use either stool or saliva samples.
There are several companies offering such testing. This page reviews the tests I have found most helpful with clients.
Diagnostechs GI panel
Diagnostechs GI Health Panel is invaluable for giving clinically relevant information, in a cost effective manner.
The following are the more important markers on their GI Health Panel.
Inflammation
- Intestinal Lysozyme: marker of colonic inflammation
- Alpha Anti-chymotrypsin: marker of GI inflammation including in the small intestine
- Calprotectin: inflammatory marker which can help to differentiate inflammatory bowel disease (Chron’s or Ulcerative Colitis) from other GI system disorders.
Sometimes people have no digestive symptoms, but elevated inflammatory markers. The inflammation may be there and cause other symptoms, such as autoimmune disease or frequent allergies.
However, there are no direct digestive symptoms.
Othertimes, people may have severe GI symptoms, but low inflammatory markers.
Some people have pathogens, or allergies that cause symptoms, but their inflammatory markers are low. You can not assume there is inflammation based upon symptoms alone.
Secretory IgA
Secretory IgA is the immune system’s first line of defense. It is secreted acrross the whole length of the digestive tract.
Its job is to bind to pathogens and alert the rest of the immune system to pathogens.
- Low total secretory IgA: supressed immunity. Oftern related to stress.
- Elevated total IgA: increased immune system activity, usually in response to a pathogen.
Specific IgA tests
Besides testing for total IgA levels, it can also be tested against specific foods or pathogens. This helps to show hidden food allergies or parasites.
Available IgA food markers
- Gliadin (wheat)
- Corn
- Soy
- Egg
- Cassein (dairy)
IgA tests for parasites
Looking at a stool sample for parasites commonly gives false negative.
Tests for IgA against specific parasites helps to lower the chance of false negatives.
In fact, over years of running this test, I‘ve seen many more times parastites found on IgA tests, then microscopic exam.
- Blastocystis hominis: estimated 2.6% of US population infected. About 50 to 80% of those infected will present with symptoms, and often diagnosed with “Irritable Bowel Syndrome.”
- Entamoeba coli: estimated 4.2% of US population infected.
- Toxoplasma gondi: estimated 40 to 50% of US population infected. Causes multiple symptoms including brain cysts leading to behavioral disorders, muscle cysts, depression, insomnia and reduced stress tolerance.
- Entamoeba histolytica: causes episodic diarrhea or perianal itch causing colon ulceration. May be locally invasive, causing liver and lung abscesses.
- Trichinella spiralis: tissue worm, causing abdominal cramping, nausea, diarrhea and muscle soreness and pain leading to fibromyalgia, edema of the upper eye lids or fever.
- Ascaris lumricoides: roundworm. The most common worm infection in the world. Causes nutritional deficiencies, reduced liver and pancreas function, intestinal colic, diarrhea, dyspepsia and spasmodic cough.
- H. pylori: common cause of stomach symptoms (they test for this using saliva IgG)
Bacterial and yeast culture
A stool culture for bacteria and yeast can quantify amounts of certain dysbiotic organisms such as candida, Klebsiella, E. coli, Streptococcus and more.
Microscopic Exam
Parasitse may still be found on microscopic exam. For comprehensive testing doing both, looking under the microscope and IgA is best.
FilmArray PCR Gastrointestinal Panel
This is a different lab test avaiable through biofiredx and is more specific for pathogenic bacteria and a few parasites.
PCR stands for polymerase chain reaction. This test looks for strands of DNA to identify specific pathogens. Sometime when there is a need to identify specific pathogens, this is the best way to do it.
The following pathogens can be identified on this test:
BACTERIA:
- Campylobacter (jejuni, coli, and upsaliensis)
- Clostridium difficile (toxin A/B)
- Plesiomonas shigelloides
- Salmonella
- Yersinia enterocolitica
- Vibrio (parahaemolyticus, vulnificus, and cholerae)
- Vibrio cholerae
DIARRHEAGENIC E. COLI/SHIGELLA
- Enteroaggregative E. coli (EAEC)
- Enteropathogenic E. coli (EPEC)
- Enterotoxigenic E. coli (ETEC) lt/st
- Shiga-like toxin-producing E. coli (STEC) stx1/stx2
- E. coli O157
- Shigella/Enteroinvasive E. coli (EIEC)
PARASITES:
- Cryptosporidium
- Cyclospora cayetanensis
- Entamoeba histolytica
- Giardia lamblia
VIRUSES:
- Adenovirus F40/41
- Astrovirus
- Norovirus GI/GII
- Rotavirus A
- Sapovirus (I, II, IV, and V)
Who may benefit from a functional digestive system test?
Since digestion effects just about every other part of the body, there are many conditions where functional tests for the digestive symptoms may be helpful. The following are a few of the most common examples:
- Anyone with chronic digestive issues such as cramps, bloating, chronic constipation or diarrhea, IBD, IBS
- Conditions of inflammation such as autoimmune disease, sleep apnea, or multiple food allergies
- Unexplained fatigue
- Chronic Candida or other yeast infection that does not easily resolve