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


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.


Akkermansia muciniphila

Optimal range: 1200000 - 100000000000 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 - 32000000 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”.



Optimal range: 0 - 99 Units

Astrovirus can cause diarrheal illness (gastroenteritis). Infants and young children are most likely to have diarrhea caused by astroviruses, but the infection also occurs in the elderly and those with compromised immune systems.


Bacteroides vulgatus

Optimal range: 0 - 2200000000 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: 3400000 - 1500000000 CFU/g stool

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


Barnesiella spp.

Optimal range: 0 - 160000000 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 - 720000000 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 - 6400000000 Units

A common component of the microbiota of the human gastrointestinal tract and in particular are amongst the first bacterial colonizers of the intestine.



Optimal range: 4 - 10 Units

Butyrivibrio crossotus

Optimal range: 5500 - 590000 CFU/g stool

Butyrivibrio‘ is a genus of bacteria in Class Clostridia. Butyrivibrio crossotus are often found in the human gut and inversely associated with obesity.



Optimal range: 0 - 50 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: 0.4 - 4.8 mg/g


Optimal range: 0.9 - 26.8 U/g


Optimal range: 0 - 0.0001 Units

Clostridium spp.

Optimal range: 170000000 - 15000000000 CFU/g stool

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


Collinsella aerofaciens

Optimal range: 14000000 - 1900000000 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 - 120000000 CFU/g stool

The abundance of Coprococcus eutactus is associated with greater bacterial gene richness in the gut.

Coprococcus is a genus of anaerobic cocci which are all part of the human faecal flora. Coprococcus includes those gram-positive, anaerobic cocci that actively ferment carbohydrates, producing butyric and acetic acids with formic or propionic and/or lactic acids. Fermentable carbohydrates are either required or are highly stimulatory for growth and continued subculture. The genus is bio-chemically closely related to Ruminococcus.


Deoxycholic acid (DCA)

Optimal range: 0.67 - 6.76 mg/g

Desulfovibrio piger

Optimal range: 0 - 18000000 CFU/g stool

Desulfovibrio piger is part of a group called Sulfate-reducing bacteria (=SRB). SRBs are normal inhabitants of the intestine in humans. This group of bacteria can “breathe” sulfate rather than oxygen. SRBs have been suspected to contribute to gastrointestinal disease due to the production of hydrogen sulfide, which can be considered toxic to the gut epithelium.


Enteroaggregative E. coli (EAEC)

Optimal range: 0 - 99 Units

Enteroaggregative Escherichia coli (EAEC) are quite heterogeneous category of an emerging enteric pathogen associated with cases of acute or persistent diarrhea worldwide in children and adults, and over the past decade has received increasing attention as a cause of watery diarrhea, which is often persistent. EAEC infection is an important cause of diarrhea in outbreak and non-outbreak settings in developing and developed countries. Recently, EAEC has been implicated in the development of irritable bowel syndrome, but this remains to be confirmed. 


Enteropathogenic E. coli (EPEC)

Optimal range: 0 - 99 Units

Enteropathogenic Escherichia coli (EPEC) is a gram-negative bacterial pathogen that adheres to intestinal epithelial cells, causing diarrhea.


Enterotoxigenic E. coli (ETEC) It/st

Optimal range: 0 - 99 Units

Enterotoxigenic Escherichia coli (E. coli), or ETEC, is an important cause of bacterial diarrheal illness. Infection with ETEC is the leading cause of travelers’ diarrhea and a major cause of diarrheal disease in lower-income countries, especially among children.


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.


Escherichia coli

Optimal range: 2 - 10 Units

Escherichia coli (CFU/g stool)

Optimal range: 90000 - 46000000 CFU/g stool

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


Faecalibacterium prausnitzii

Optimal range: 58000000 - 4700000000 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

The fecal occult blood test (=FOBT) looks for blood in your feces. “Occult” (=hidden) means that the blood amount is so small that it cannot be seen with the naked eye. The bleeding does not change the color of the stool or result in visible bright red blood. Therefore, the blood is found only by testing the stool for blood in the laboratory.


Fecal secretory IgA

Optimal range: 0 - 680 mcg/g

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


Firmicutes/Bacteroidetes (F/B Ratio)

Optimal range: 12 - 620 Ratio

The F/B ratio provides an estimate of the predominance of two major phyla of commensal organisms, which has been associated with a number of metabolic disorders.



Optimal range: 0 - 0.0001 Units

Fusobacterium spp.

Optimal range: 0 - 240000 CFU/g stool

Fusobacterium spp. present in the oral and gut flora is carcinogenic and is associated with the risk of pancreatic and colorectal cancers. Fusobacterium spp. is also implicated in a broad spectrum of human pathologies, including Crohn’s disease and ulcerative colitis (UC).

Fusobacterium is very rarely found among the usual gut bugs, but it appears to flourish in colon cancer cells.


H. PYLORI, Antigen

Optimal range: 0 - 0 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: 8300000 - 5200000000 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

Optimal range: 1.2 - 29.1 mg/g

Long chain fatty acids are a fecal fat. Fecal fats also include triglycerides, cholesterol and phospholipids. They are derived predominately from the dietary ingestion of fat, and provide important clues about digestion and absorption.


M2 Pyruvate Kinase

Optimal range: 0 - 4 U/mL

Methanobrevibacter smithii

Optimal range: 0 - 86000000 CFU/g stool

Methanobrevibacter smithii is highly prevalent in the human gut. Lower counts have been associated with obesity while higher amounts have been associated with anorexia.


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

This short-chain fatty acid (SCFA) is produced as a result of the fermentation of dietary fiber, particularly gums and pectins, by certain bacteria that inhabit the intestines (particularly probiotic bacteria such as Lactobacilli and Bifodobacteria species).

An n-butyrate level within the reference range is first and foremost then, an indicator that such health promoting bacteria are present in sufficient amounts.


Odoribacter spp.

Optimal range: 0 - 80000000 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 - 15000000 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.



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. 


Plesiomonas shigelloides

Optimal range: 0 - 999 Units

Plesiomonas shigelloides is a Gram-negative bacillus found in aquatic environments that has been primarily associated with sporadic cases and outbreaks of diarrheal disease.


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: 140000 - 16000000 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

Products of Protein Breakdown, which includes isovalerate, valerate and isobutyrate are produced by bacterial fermentation of proteinaceous material (polypeptides and amino acids) in the distal colon.

Products of Protein Breakdown (Total) is a set of markers of undigested protein reaching the colon.


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.


Pseudoflavonifractor spp.

Optimal range: 420000 - 130000000 CFU/g stool

Pseudoflavonifractor spp. has been positively associated with weight loss.


Putrefactive SCFAs

Optimal range: 1.3 - 8.6 micromol/g

Roseburia spp.

Optimal range: 130000000 - 12000000000 CFU/g stool

Roseburia is a genus (=group) of 5 species of bacteria named in the 1980s after American microbiologist Theodor Rosebury. Bacteria in this genus are notable for breaking down sugar, and producing a short-chain fatty acid called butyrate which is important as a food for the cells lining the colon.



Optimal range: 0 - 99 Units

Rotavirus affects the intestines and causes vomiting and diarrhea. This infection is especially common in young children, but it can affect adults, too. A rotavirus infection causes a condition called viral gastroenteritis. 


Ruminococcus spp.

Optimal range: 95000000 - 1600000000 CFU/g stool

The Ruminococcus bacteria in our gut microbiomes play a major role in helping us digest resistant starches - the complex carbohydrates found in high fiber foods such as lentils, beans, and unprocessed whole grains.


Short-Chain Fatty Acids (SCFA), Total

Optimal range: 23.3 - 200 micromol/g

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.



Optimal range: 0.3 - 2.8 mg/g

Most of the fats in our diet are in the form of triglycerides. These are broken down by an efficient digestive system into smaller fragments that can then be absorbed from the small intestine.


Veillonella spp.

Optimal range: 120000 - 55000000 CFU/g stool

Veillonella are anaerobic, gram-negative cocci, part of the normal flora of the mouth, gastrointestinal tract, and vaginal tract.


Vibrios are inhabitants of estuarine and fresh waters and some species are pathogenic to humans, and marine vertebrates and invertebrates. In humans, some species of vibrios can cause gastroenteritis following ingestion of contaminated food or water and septicemia when pre-existing cuts or abrasions on skin come in contact with contaminated water or seafoods.


Zonulin Family Peptide

Optimal range: 22.3 - 161.1 ng/mL

Zonulin is a protein modulator of intestinal tight junctions and is used to assess intestinal permeability. It can be used for assessing impaired gut barrier function for several autoimmune and metabolic conditions including celiac disease, type 1 diabetes and insulin resistance.