Fecal fat test
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191507538
2008-02-14T21:47:57Z
WhatamIdoing
1998764
moved [[Fecal fat]] to [[Fecal fat test]] over redirect: Complete name
In [[medicine]], a '''fecal fat''' test is a diagnostic test for [[fat]] [[malabsorption]] conditions (also referred to as [[steatorrhea]]).
==Background==
In the [[small intestine]], dietary fat (primarily [[triglyceride]]s) is digested by [[enzyme]]s such as [[pancreatic lipase]] into smaller molecules which can be absorbed through the wall of the small intestine and enter the [[Circulation (physiology)|circulation]] for [[metabolism]] and storage. As [[fat]] is a valuable nutrient, human [[feces]] normally contain very little undigested fat. However, a number of diseases of the pancreas and gastrointestinal tract are characterized by fat malabsorption.
Examples of such diseases are:
* disorders of exocrine [[pancreas|pancreatic]] function, such as [[chronic pancreatitis]], [[cystic fibrosis]] and [[Shwachman-Diamond syndrome]] (these are characterized by deficiency of pancreatic digestive enzymes)
* [[celiac disease]] (in which the fat malabsorption in severe cases due to inflammatory damage to the integrity of the intestinal lining)
* [[short bowel syndrome]] (in which much of the small intestine has had to be surgically removed and the remaining portion cannot completely absorb all of the fat).
*[[small bowel bacterial overgrowth syndrome]]
==Microscopy==
In the simplest form of the fecal fat test, a random fecal specimen is submitted to the [[hospital laboratory]] and examined under a [[microscope]] after [[staining]] with a [[Sudan III]] or [[Sudan IV]] dye ("[[Sudan stain]]ing"). Visible amounts of fat indicate some degree of fat malabsorption..
==Quantitative fecal fat test==
Quantitative fecal fat tests measure and report an amount of fat. This usually done over a period of three days, the patient collecting all of their feces into a container.
The container is thoroughly mixed to homogenize the feces, this can be done with a [[paint mixer]]. A small sample from the feces is collected. The fat content is extracted with [[solvent]]s and measured by [[saponification]] (turning the fat into [[soap]]).
Normally up to 7 [[gram]]s of fat can be malabsorbed in people consuming 100 grams of fat per day. In patients with [[diarrhea]], up to 12 grams of fat may be malabsorbed since the presence of diarrhea interferes with fat absorption, even when the diarrhea is not due to fat malabsorption.
{{Unreferenced|date=August 2007}}
[[Category:Gastroenterology]]
[[Category:Feces]]
[[Category:Stool tests]]