| Humoralpathologisches Forschungslabor | Stool test
Pancreas-elastase is an enzyme in pancreas which is of importance for the intestinal protein digestion.
In excretory pancreas insufficiency as in chronic intermittent pancreatitis, the secretorial function in pancreas is affected. Extremely low elastase values in faeces (< 100µg/g of faeces) indicate this condition. Clinical symptoms of milder forms of pancreas insufficiency, which frequently occur in elderly people, often go unnoticed. The symptoms may appear only as change of faeces consistency and meteorism. By examination of the nutritional uptake, an increased number of undigested components of striated muscle can be analyzed.
Should suspicion on excretory pancreas insufficiency remain, this should be confirmed, if possible, through repeated tests of pancreas-elastase in faeces.
Analysis of pancreas-elastase aims at verifying an exocrine pancreas insufficiency. Symptoms of this are recurrent discomfort from the upper part of the abdomen, heart burn, sensation of bloating, meteorism, steatorrhoea.
Normal value: 200-20.000µg/g of faeces
Note: To enable a reliable analysis, substituting preparations should be discontinued at least 3 days prior to testing. Otherwise, high values, simulating a physiological situation, can be obtained. False values can also appear in case of a strongly increased presence of proteolytic intestinal bacteria. Considering possible differential diagnosis, by low elastase values the total phenol values in morning urine should be defined.
D2 Examination of bile acids in faeces
Bile acids are excreted in the lumen of the small intestine. Their function is emulgation of nutritional fat in the fluid environment of the intestinal content. This course is a prerequisite for resorption through the mucosa. The essential degradation of complex fat takes place through pancreas lipases. Moreover, bile acids promote the intestinal peristaltic and stimulate the pancreas secretion.
Physiologically, approximately 97% of the bile acids in the small intestine are again resorbed in the small intestine, mainly ileum, and are renewed through the enterohepatical cycle to be used for digestion. Non-resorbed bile acids are bacterially deconjugated in colon and exit with the faeces. A bacterial growth over the small intestine can, already in this section, lead to deconjugation of the bile acids. Deconjugated bile acids inhibit the water resorption and results in a secretion of fluid and electrolytes in the intestinal lumen. The intestinal peristaltic and the permeability simultaneously increase in the intestinal mucosa. Clinically, this appears as watery thin diarrhoea.
Additionally, deconjugated bile acids cause structural changes in the intestinal mucosa. Their complicity in colon cancer is being discussed. If a lengthy loss of bile acids remains, due to decreased synthesis in the liver, they can no longer act equalizing, but affect the digestion of fat. Clinically this decompensated loss of bile acids manifests itself as steatorrhoea.
Defining bile acids in faeces is recommended because when persistent diarrhoea also is accompanied by an increase of fat, a suspicion on decompensated loss of bile acids remains. In these cases they are also used for diagnostics of collagen diarrhoea.
Normal value: < 1,7µmol/g of faeces
D3 Fat and nitrogen in faeces
Fat: Nutritional fat is decomposed almost completely by pancreas enzymes and the decomposing components (glycerine, free fatty acids, mono- and diglycerides) are resorbed through the intestinal mucosa.
The increased microscopic signs of neutral fat and/or fatty acids in faeces confirm clinical suspicion on a fat-mal-assimilation.
Normal value: < 4,5g/100g of faeces
Nitrogen: An increased amount of nitrogen in faeces indicates a disturbance of the protein digestion or protein resorption in the small intestine.
Upon suspicion of mal-assimilatory disturbances, a definition of the nitrogen content is an important differential diagnostic aid.
Normal value: < 1,g/100g of faeces
D4 Lactic acid (D- and L-form) in faeces
The D- and L-forms of lactic acid are the product of the bacterial metabolism in the intestine. Originating substrates for these are mono- and complex carbohydrates.
Lactic acid is normally not detectable or only in small amounts. Increased lactic acid values in faeces give a first hint of intestinal overgrowth (SBOG) as well as acquired or congenital carbohydrate intolerance (lactose-, glucose-, galactose-, saccharose intolerances.
Normal value: < 10 mg/g of faeces
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