In this category we look at digestion, absorbtion, gut immunology, gut metabolism, gut microbiology, beneficial bacteria and fecal fats.

Acetate (Stool)

Optimal range: 48.1 - 69.2 %

Acetate is the most abundant SCFA in the colon and makes up more than half of the total SCFA detected in feces. These beneficial SCFA have anti-inflammatory properties, provide energy to nourish the colonic epithelial cells and intestinal microbiota, and exert numerous positive effects on gut homeostasis.


Adenovirus 40/41

Optimal range: 0 - 9000000000 Units

Adenovirus serotypes 40 and 41 cause acute gastroenteritis (inflammation of the stomach and intestines) primarily in children.


Akkermansia muciniphila

Optimal range: 1200000 - 19000000 CFU/g stool

Akkermansia muciniphila may represent 3–5% of the microbial composition in the healthy human intestinal tract, and have a crucial role in the regulation of the gut barrier and other homeostatic and metabolic functions.


Anaerotruncus colihominis

Optimal range: 0 - 3.2 CFU/g stool

Anaerotruncus colihomonis (pronounced “an-AERO-trunk-us colly-HOM-in-iss”) is a newly described bacterial genus and species isolated from the stool specimens of children. Its clinical significance, however, is unknown.

The species is found only relatively infrequently in the human gut. It comes from the genus Anaerotruncus, which contains just this one species. The genus name comes from the Greek words “an” and “aero”, meaning respectively “without” and “air”, and the Latin word “truncus”, which means “stick”—making the overall name “a stick that lives without air”, since the cells of this bacterial genus are rod-like in shape and live in the absence of oxygen. The species name “colihominis” means “of the gut of man”.


Ancylostoma duodenale

Optimal range: 0 - 0.00001 Units

The distribution of hookworm (Necator americanus and Ancylostoma duodenale) is worldwide, with particular prevalence in rural areas of the moist tropics where there is inadequate sanitation and people walk barefoot. The two species produce indistinguishable thin-walled eggs that hatch in soil. Infection is usually acquired by walking barefoot in soil contaminated with human faeces. The larvae undergo several moults before infective larvae are produced.


Anti-gliadin IgA

Optimal range: 0 - 157 U/L

Antigliadin antibodies (AGAs) are antibodies of the IgA and IgG classes found in the serum of celiac disease patients. These antibodies mainly target gliadin-derived peptides, which are the main proteins of gluten. AGAs are not specific for celiac disease as they are also found in patients with other gastrointestinal diseases such as gastritis, gastroenteritis, and IBD.


Ascaris lumbricoides

Optimal range: 0 - 0.00001 Units

Ascaris lumbricoides, an intestinal roundworm, is one of the most common helminthic human infections worldwide.

Ascaris lumbricoides is the largest intestinal nematode of man. The female worms are larger than the males and can measure 40 cm in length and 6 mm in diameter. They are white or pink and are tapered at both ends. 


Bacillus spp.

Optimal range: 0 - 149999 Units

Bacillus spp. are spore forming bacteria, ubiquitous in the environment. B. cereus in particular is a frequently recognized cause of toxin-induced acute gastroenteritis.

Other infections caused by this genus include:

  • sepsis
  • pneumonia
  • endocarditis
  • central nervous system (CNS) and ocular infections


Bacteroides fragilis

Optimal range: 1600000000 - 250000000000 Units

Bacteroides vulgatus

Optimal range: 0 - 2.2 CFU/g stool

Bacteroides vulgatus is among the most commonly isolated microbes from the human gastrointestinal tract, and it has been found to constitute part of the core gut microbiota in healthy humans.


Bacteroides-Prevotella group

Optimal range: 3.4 - 1500 CFU/g stool

The predominant genera in the human colonic microbiota are Bacteroides and Prevotella, which belong to the major phyla Bacteroidetes.



Optimal range: 861000000000 - 3310000000000 Units

Barnesiella spp.

Optimal range: 0 - 1.6 CFU/g stool

Barnesiella ssp. is a small group of two species of bacteria that are usually only found at reasonably low levels in the gut.


Beneficial SCFAs

Optimal range: 13.6 - 150 micromol/g

Short chain fatty acids are saturated fatty acids consisting of no more than 6 carbons. The most common forms—acetate, propionate, and butyrate—are also helpful for colon and overall health. Thus, they are called beneficial SCFAs.



Optimal range: 368 - 6266 U/g

Beta-glucuronidase is an enzyme produced by certain unfriendly gut bacteria. A proper balance of beta-glucuronidase is essential for good health and disease prevention.


Bifidobacterium longum

Optimal range: 0 - 72 CFU/g stool

Bifidobacterium longum is a specific species of microscopic non-pathogenic bacteria found naturally in the gastrointestinal tracts of humans as well as in most other animals.


Bifidobacterium spp.

Optimal range: 0 - 64 Units


Optimal range: 4 - 10 Units

Blastocystis hominis

Optimal range: 0 - 1999 Units

Butyrivibrio crossotus

Optimal range: 5500 - 590000 CFU/g stool

C. difficile, Toxin A

Optimal range: 0 - 999 Units

C. difficile, Toxin B

Optimal range: 0 - 999 Units


Optimal range: 0 - 49.9 mcg/g

Calprotectin is a protein that binds to both calcium and zinc. Fecal calprotectin levels are abnormally increased in people with intestinal inflammation, thus it is useful for distinguishing between inflammatory and non-inflammatory diarrhea.



Optimal range: 0 - 999 Units

When people worry about eating undercooked chicken, they usually focus on getting sick from salmonella bacteria. But another common type of bacteria called campylobacter can also make you ill if you eat poultry that isn’t fully cooked.


Candida albicans

Optimal range: 0 - 499 Units

Candida spp.

Optimal range: 0 - 4999 Units

Chilomastix mesnili

Optimal range: 0 - 99999 Units

Cholesterol (Stool)

Optimal range: 0.4 - 4.8 mg/g


Optimal range: 0.9 - 26.8 U/g

Citrobacter freundii

Optimal range: 0 - 499999 Units

Citrobacter spp.

Optimal range: 0 - 4999999 Units


Optimal range: 0 - 0.0001 Units

Clostridium spp.

Optimal range: 17 - 1500 Units

Clostridium spp. is part of the intestinal indigenous microbiota and they can produce several endogenous infections.


Collinsella aerofaciens

Optimal range: 14 - 1900 CFU/g stool

Collinsella aerofaciens is a group of bacteria found in the gut and also on the surface of the tongue. It is named after the microbiologist Matthew Collins.


Coprococcus eutactus

Optimal range: 0 - 120 CFU/g stool


Optimal range: 0 - 999999 Units

Cyclospora spp.

Optimal range: 0 - 49999 Units


Optimal range: 0 - 99999 Units

Deoxycholic acid (DCA)

Optimal range: 0.67 - 6.76 mg/g

Desulfovibrio piger

Optimal range: 0 - 18000000 CFU/g stool

Dientamoeba fragilis

Optimal range: 0 - 99999 Units

E. coli O157

Optimal range: 0 - 999 Units


Optimal range: 201 - 2000 ug/g

Endolimax nana

Optimal range: 0 - 9999 Units

Entamoeba coli

Optimal range: 0 - 4999999 Units

Entamoeba histolytica

Optimal range: 0 - 9999 Units

Enterobacter spp.

Optimal range: 1000000 - 50000000 Units

Enterococcus faecalis

Optimal range: 0 - 9999 Units

Enterococcus faecium

Optimal range: 0 - 9999 Units

Enterococcus spp.

Optimal range: 190000 - 200000000 Units

Enterohemorrhagic E. coli

Optimal range: 0 - 999 Units

Enterotoxigenic E. coli LT/ST

Optimal range: 0 - 999 Units

Eosinophil Protein X

Optimal range: 0 - 4.6 mcg/g

Eosinophil Protein X is a water-soluble protein that is found in eosinophils. Fecal Eosinophil Protein X levels are abnormally increased in people with intestinal inflammation where high concentrations of eosinophils may be found.


Epstein Barr Virus

Optimal range: 0 - 999999 Units

Escherichia coli

Optimal range: 2 - 10 Units

Escherichia coli (CFU/g stool)

Optimal range: 9 - 4600 CFU/g stool

Escherichia coli (E. coli) is a type of bacteria that normally live in the intestines of people and animals.


Escherichia spp.

Optimal range: 3700000 - 3800000000 Units

Faecalibacterium prausnitzii

Optimal range: 58 - 4700 CFU/g stool

Faecalibacterium prausnitzii is one of the most important bacteria in the human gut flora and makes up to 5-10% of the total number of bacteria detected in stool samples from healthy humans. Faecalibacterium prausnitzii has a crucial role in maintaining gut physiology and host wellbeing.


Fecal Fat, Total

Optimal range: 3.2 - 38.6 mg/g

A fecal fat test helps your doctor identify pancreatic or intestinal disorders. It can indicate your body isn’t creating enough enzymes or there is malabsorption.


Fecal Occult Blood

Optimal range: 0 - 0.0001 Units

Fecal secretory IgA

Optimal range: 0 - 885 mcg/g

Fecal Secretory IgA is a marker of gut secretory immunity and barrier function.



Optimal range: 57000000000 - 304000000000 Units

Firmicutes:Bacteroidetes Ratio

Optimal range: 0 - 0.99 Ratio


Optimal range: 0 - 0.0001 Units

Fusobacterium spp.

Optimal range: 0 - 240000 CFU/g stool

Geotrichum spp.

Optimal range: 0 - 299 Units


Optimal range: 0 - 4999 Units

Giardia infection (giardiasis) is one of the most common causes of waterborne disease in the United States.


Helicobacter pylori

Optimal range: 0 - 999 Units

Klebsiella pneumoniae

Optimal range: 0 - 49999 Units

Klebsiella spp.

Optimal range: 0 - 4999 Units

Lactobacillus species

Optimal range: 2 - 10 Units

Lactobacillus species is a type of bacteria. There are lots of different species of lactobacillus.

Lactobacillus bacteria are commonly found in the human gut, mouth and vagina. They are considered generally as “good bacteria”, and in fact may contribute to good health, often being included in probiotic supplements. These bacteria are characterized by their ability to produce lactic acid as a byproduct of glucose metabolism.


Lactobacillus spp.

Optimal range: 83 - 52000 Units

Lactobacillus species is a type of bacteria. There are lots of different species of lactobacillus.

Lactobacillus bacteria are commonly found in the human gut, mouth and vagina. They are considered generally as “good bacteria”, and in fact may contribute to good health, often being included in probiotic supplements. These bacteria are characterized by their ability to produce lactic acid as a byproduct of glucose metabolism.


LCA / DCA Ratio

Optimal range: 0.39 - 2.07 Ratio

LCA and DCA are secondary bile acids. These secondary bile acids are associated with disease. An LCA:DCA ratio greater than 1 is associated with increased risk of gallstones, breast cancer, and colorectal cancer. 


Lithocholic acid (LCA)

Optimal range: 0.65 - 5.21 mg/g

Long-Chain Fatty Acids (Stool)

Optimal range: 1.2 - 29.1 mg/g

Methanobrevibacter smithii

Optimal range: 0 - 86000000 CFU/g stool

Microsporidium spp.

Optimal range: 0 - 4999 Units

Morganella spp.

Optimal range: 0 - 999 Units

n-Butyrate (Stool)

Optimal range: 11.8 - 33.3 %

N-Butyrate is one of the short-chain fatty acids produced by Lactobacillus and Bifidobacteria in the colon. It becomes a food supply capable of providing up to 30% of the energy needed by colon cells. N-butyrate improves colon health.


n-Butyrate Concentration

Optimal range: 3.6 - 100 micromol/g

Necator americanus

Optimal range: 0 - 0.0001 Units

Norovirus GI/II

Optimal range: 0 - 9000000 Units

Odoribacter spp.

Optimal range: 0 - 80000 CFU/g stool

The bacteria are found in the human gut where they are considered “commensal”, which means “eating from the same dish”. They exist in the human body without either helping or hindering us.


Oxalobacter formigenes

Optimal range: 0 - 1.5 CFU/g stool

Oxalobacter formigenes is a bacterium that colonizes the colon of a substantial proportion of the normal population and metabolizes dietary and endogenous oxalate and hence reducing the incidence of kidney stones.


Pancreatic Elastase 1

Optimal range: 200 - 1000 mcg/g

Pancreatic elastase is an enzyme that digests protein. It’s only produced by the pancreas and when it is seen in the stool, it’s an excellent biomarker of how well the pancreas is performing.


Pentatrichomonas hominis

Optimal range: 0 - 99 Units

Phospholipids (Stool)

Optimal range: 0.2 - 6.9 mg/g

The enzyme LCAT transesterifies cholesterol in the blood with fats from lecithin. When this happens as it should, HDL, VLDL and LDL lipoprotein particles are remodeled and cholesterol is moved out of the blood. The Phospholipid test looks for LCAT deficiency. 


Prevotella copri

Optimal range: 0 - 9999999 Units

Prevotella copri is a gut bacteria that may cause rheumatoid arthritis. Studies consistently find different bacterial patterns in people with inflammatory arthritis vs controls.


Prevotella spp.

Optimal range: 140 - 16000 CFU/g stool

Prevotella spp. is known for its ability to degrade complex plant polysaccharides (carbohydrates) and fiber.


Products of Protein Breakdown (Total)

Optimal range: 1.8 - 9.9 micromol/g

Propionate (Stool)

Optimal range: 0 - 29.3 %

Propionate is among the most common short-chain fatty acids produced in the human gut in response to indigestible carbohydrates (fiber) in the diet.


Proteus mirabilis

Optimal range: 0 - 999 Units

Proteus spp.

Optimal range: 0 - 49999 Units

Pseudoflavonifractor spp.

Optimal range: 42 - 13000 CFU/g stool

Pseudomonas aeruginosa

Optimal range: 0 - 499 Units

Pseudomonas spp.

Optimal range: 0 - 9999 Units

Putrefactive SCFAs

Optimal range: 1.3 - 8.6 micromol/g

Rodotorula spp.

Optimal range: 0 - 999 Units

Roseburia spp.

Optimal range: 13 - 1200 CFU/g stool

Ruminococcus spp.

Optimal range: 95 - 1600 CFU/g stool


Optimal range: 0 - 9999 Units

Secretory IgA

Optimal range: 510 - 2010 ug/g

Shiga-like Toxin E. coli stx1

Optimal range: 0 - 999 Units

Shiga-like Toxin E. coli stx2

Optimal range: 0 - 999 Units

Short-Chain Fatty Acids (SCFA), Total

Optimal range: 23.3 - 200 micromol/g

Staphylococcus aureus

Optimal range: 0 - 499 Units

Staphylococcus spp.

Optimal range: 0 - 9999 Units


Optimal range: 0 - 14.9 %

Stool pH

Optimal range: 6.1 - 7.9 pH

A fecal pH test is one where a specimen of feces is tested for acidity in order to diagnose a medical condition.

  • Human feces is normally acidic.
  • The average pH for a healthy person is a pH of 6.6.

Stool pH is dependent in part on fermentation of sugars. Colonic fermentation of normal amounts of carbohydrate sugars and production of fatty acids accounts for the normally slightly acidic pH.


Streptococcus spp.

Optimal range: 0 - 999 Units

Taenia spp.

Optimal range: 0 - 0.0001 Units

Trichuris trichiura

Optimal range: 0 - 0.0001 Units

Triglycerides (Stool)

Optimal range: 0.3 - 2.8 mg/g

Veillonella spp.

Optimal range: 12 - 5500 CFU/g stool

Vibrio cholerae

Optimal range: 0 - 99999 Units

Virulence Factor, babA

Optimal range: 0 - 0.0001 Units

Virulence Factor, cagA

Optimal range: 0 - 0.0001 Units

Virulence Factor, dupA

Optimal range: 0 - 0.0001 Units

Virulence Factor, iceA

Optimal range: 0 - 0.0001 Units

Virulence Factor, oipA

Optimal range: 0 - 0.0001 Units

Virulence Factor, vacA

Optimal range: 0 - 0.0001 Units

Virulence Factor, virB

Optimal range: 0 - 0.0001 Units

Virulence Factor, virD

Optimal range: 0 - 0.0001 Units

Yersinia enterocolitica

Optimal range: 0 - 99999 Units

Zonulin, Stool

Optimal range: 22.3 - 161.1 ng/mL