Stool
Digestion
Test digestive capacity via stool. Analyzes proteins, fats, and carbohydrates.
€ 65,00
All tests
Gut · Stool
Fat soaps (feces)
Fatty acids bound to calcium in the stool; gives an impression of fat absorption, but depends heavily on diet.
At a glance
- Measured in stool
- In 1 test panel
- No special preparation
Explanation
Fat soaps (feces): what is measured?
When fat has been broken down into fatty acids but is not absorbed, these fatty acids can bind to calcium and magnesium in the gut. This forms fat soaps. The laboratory looks at or measures how many fat soaps are in the stool. A lot of fat soaps more likely fits a problem with the absorption of fat in the small intestine than a problem with its breakdown.
What can it detect?
- A sign of reduced absorption of fat in the small intestine
Result
What does the result mean?
Fat soaps (feces) too high
More fat soaps than usual can be caused by a diet rich in fat and calcium, a lot of dairy or calcium tablets, or fast passage through the gut. A persistently raised value may fit poorer fat absorption in the small intestine, for example with celiac disease, or too little bile in the gut. Constipation with hard stool can also go together with a lot of fat soaps.
Fat soaps (feces) too low
Few fat soaps is the normal result. A low value has no further meaning.
After an abnormal result
Without symptoms, an abnormal result from this test usually needs no follow-up. With symptoms that fit poor digestion, the GP can request pancreatic elastase in the stool or a blood test for celiac disease, and if needed refer you to a gastroenterologist or internist (specialist in internal medicine).
Reliability
How reliable is the test?
Food remnants in a single stool sample mainly say something about what you have eaten and how quickly the food passed through the gut. How well the result shows or rules out poor digestion has not been well studied, neither in people without symptoms nor in people with bowel symptoms. If poor fat digestion (malabsorption) is suspected, the specialist may have fat measured in stool collected over a few days. For pancreatic function, pancreatic elastase in the stool has been studied better.
What can affect the result?
- Food in the days before sample collection (fat, meat, raw vegetables, legumes, dairy, sugars) largely determines the result.
- Diarrhea or, on the contrary, constipation changes the result, because the speed through the gut determines how much is digested.
- One stool sample gives a snapshot; the composition differs from day to day.
- Medicines such as laxatives, antibiotics, stomach acid inhibitors, pancreatic enzymes and weight-loss medicines that block fat absorption (orlistat) affect the result.
Who it is for
Who is the test useful for?
Useful for
Because diet strongly determines the result, this test says little in people without symptoms, and even with symptoms it does not identify a cause. With symptoms that may fit poor digestion, such as long-lasting fatty or mushy stools, unintended weight loss or long-lasting diarrhea, testing through the GP is the right route. Pancreatic elastase in the stool and a blood test for celiac disease are then more targeted first tests. With blood in the stool, unintended weight loss or new bowel symptoms after the age of 50, this test is no substitute for a visit to the GP.
How common is it?
There are no Dutch figures on how often an abnormal result for these tests occurs. Bowel symptoms themselves are common: according to the guideline, irritable bowel syndrome affects about 4 in 100 adults. Conditions in which food is truly poorly digested, such as chronic inflammation of the pancreas, are much rarer.
Dutch medical specialists' guidelines (FMS) on irritable bowel syndrome (NHG and NVMDL) and chronic pancreatitis
Get tested
Fat soaps (feces): test panels
Fat soaps (feces) is part of these test panels. You order online and have your blood drawn at a collection point or collect the sample at home.
Evidence
Sources
This explanation is based on Dutch guidelines and independent information. It is general information, not a diagnosis. Discuss an abnormal result with your GP.
More about risks and resultsMore explanations
Other tests: Gut
- Acetate and propionate production
- Acetate- and propionate-forming bacteria
- Acetic acid (feces)
- Acetic acid, relative (feces)
- Akkermansia, activity
- Alpha-1 antitrypsin (feces)
- Anti-gliadin IgA (feces)
- Anti-transglutaminase IgA (feces)
- Aspergillus fumigatus (feces)
- Aspergillus niger (feces)
- Bacteroides group, activity
- Beta-defensin 2 (feces)