Malabsorption syndrome is a digestive disorder that prevents the efficient absorption of nutrients from the foods you eat. It is a prevalent health concern, affecting 10-25% of people, and is a poor prognostic factor for health and longevity (18).
Fat malabsorption, the inability to absorb fats from the small intestine, is one of the most common types of malabsorption. Fat malabsorption disorders can cause unpleasant changes to bowel habits and are often associated with deficiencies of fat-soluble vitamins (2). Therefore, diagnosing these conditions and monitoring their treatment is important for improving patient outcomes. The fecal steatocrit test is a valuable diagnostic tool in this context.
[signup]
Understanding Fecal Steatocrit
Normally, when you eat foods containing fat, your body breaks it down in a few steps to absorb it properly. First, your stomach starts the digestion process, but most of the work happens in the small intestine. Here, bile from the liver mixes with the fat, breaking it down into smaller droplets. Then, enzymes from the pancreas further break down these droplets into tiny molecules called fatty acids and glycerol. These molecules are absorbed through the small intestine's lining and enter the bloodstream. (20)
Fat malabsorption occurs when the digestive system fails to digest and absorb fats properly. Fats that aren't absorbed in the small intestine travel through the gastrointestinal tract and are eliminated in stool (poop). Fat malabsorption causes steatorrhea, the presence of excess fat in the stool, which leads to oily, bulky, and foul-smelling bowel movements.
The 72-hour fecal fat excretion test is the gold standard for diagnosing steatorrhea. However, the test requires a three-day stool collection by the patient and accurate results depend upon the patient correctly adhering to a high-fat diet beforehand.
The fecal steatocrit test is an alternative to the 72-hour stool collection that measures the proportion of fat in a single stool sample to evaluate the extent of fat malabsorption.
Acid steatocrit is a variation of the fecal steatocrit test that involves treating the stool sample with acid, which helps break down fat more completely. This treatment makes the test more accurate than the standard fecal steatocrit test. Compared to the 72-hour stool test, the acid steatocrit test correctly identifies all cases of steatorrhea 100% of the time, correctly rules out those without it 95% of the time, and has a 90% chance of being correct when performed on a random stool sample (1).
Clinical Applications of Fecal Steatocrit
The fecal steatocrit test is often one of the first tests a doctor will order when they suspect fat malabsorption syndromes to confirm the diagnosis and quantify the severity (2).
Steatorrhea can be caused by many underlying health conditions, including (36):
- Decreased pH (i.e., increased acidity) in the duodenum destroys pancreatic acids. This is commonly caused by Zollinger-Ellison syndrome, which is a rare condition in which a tumor in the pancreas or duodenum causes the stomach to produce too much acid.
- Small intestinal diseases can reduce the absorptive surface area of the small intestine. Examples include Crohn's disease, celiac disease, and surgical removal of a portion of the small intestine.
- Impaired bile acid synthesis or transport into the small intestine negatively impacts fat digestion and absorption. Liver disease and cholestasis (decreased bile flow through the bile ducts) can result in a bile acid-deficient state.
- The overgrowth of bacteria in the small intestine, as seen in small intestinal bacterial overgrowth (SIBO), can break down bile acids, making them ineffective in fat digestion and absorption processes.
- Exocrine pancreatic insufficiency (EPI) is the inability of the pancreas to synthesize its digestive enzymes in adequate amounts. This often results from chronic pancreatitis, cystic fibrosis, celiac disease, and Zollinger-Ellison syndrome.
- Abetalipoproteinemia is a rare genetic condition that results in impaired ability to package and transport fats in proteins called lipoproteins.
Beyond diagnosis, fecal steatocrit testing can help doctors monitor treatment for fat malabsorption disorders. The fecal steatocrit test can assess how well the therapy is working by measuring changes in stool fat content over time. This allows healthcare providers to adjust treatments accordingly.
Procedure: How Fecal Steatocrit is Measured
The fecal steatocrit test requires patients to collect a stool sample, following these general instructions:
- Patients should be given a clean, dry collection container by their healthcare provider or lab.
- Avoid contaminating the sample by urinating before starting and taping the provided liner onto the toilet seat.
- Collect the sample by pooping onto the liner and using a disposable spatula to scoop a sample of the stool into the collection container.
- Tightly seal the container to prevent leakage. On the label provided, write your name, date, and time of collection.
- Store the sample in a cool place until you can deliver it to the lab. The sample should be returned to the lab as soon as possible after collection.
Patients may be asked to consume a high-fat diet before the test. If this is the case, patients should consume 100 grams of fat daily for one to three days before collecting stool. This can be achieved by eating high-fat foods like butter, oils, full-fat dairy products, meat, and nuts.
To determine steatocrit results, the stool sample is processed by spinning it in a centrifuge, which separates the fat from the rest of the stool. The fat content is then reported as a percentage, calculated by comparing the volume of the fatty layer to the volume of the liquid-free part of the stool. This percentage shows how much fat is in the stool sample. (25)
Understanding Fecal Steatocrit Results
Normal steatocrit level is less than 15% of the stool volume.
High fecal steatocrit levels are suggestive of fat malabsorption, but it is not diagnostic for any one health condition that is responsible for causing steatorrhea. After receiving abnormal results, healthcare providers should conduct a thorough clinical evaluation to identify the underlying cause of fat malabsorption. Depending on the suspected condition, this may involve additional diagnostic tests, such as additional stool or blood testing, imaging studies, and endoscopy. (2)
Results should also be interpreted in the context of the patient's health history, as high levels may be caused by excessive dietary fat intake or taking medications that affect fat absorption, such as bile acid sequestrants or orlistat.
Low steatocrit values, although less common, may be caused by low-fat diets (12).
Management of Conditions Associated with High Fecal Steatocrit
Dietary adjustments are often the first step in managing the symptoms of fat malabsorption. Patients may be advised to follow a low-fat diet to reduce symptoms. However, long-term adherence to a low-fat diet is associated with malnutrition. Therefore, dietary fat restriction is no longer recommended as a mainstay treatment option in managing chronic conditions, such as EPI (2).
Eating smaller, more frequent meals can provide symptomatic relief without risking malnutrition associated with fat restriction (36).
The management of fat malabsorption disorders also requires addressing the underlying cause. Examples include:
- Pancreatic enzyme replacement therapy (PERT) is the primary treatment for EPI. PERT involves supplementing pancreatic enzymes (amylase, lipase, and protease) with meals to replace the digestive enzymes the pancreas is not making. These supplements improve fat digestion and absorption, thereby reducing steatorrhea and improving nutritional status. (36)
- Patients with celiac disease require a strict gluten-free diet to prevent irreversible damage to the small intestine, allow for intestinal healing, and improve nutrient absorption.
- SIBO treatment encompasses antimicrobial therapy (with antibiotics or herbs), dietary modifications, and prokinetic therapy to prevent recurrence.
Fat-soluble vitamins (A, D, E, and K) rely on proper fat absorption to be effectively utilized by the body. When fat malabsorption occurs, it can result in deficiencies of these vitamins. Therefore, screening for, correcting, and preventing these deficiencies is also a standard part of managing fat malabsorption. This can be done through supplementation or by increasing the intake of foods rich in these vitamins:
- Vitamin A: fish oil, butter, orange vegetables
- Vitamin D: cod liver oil, mushrooms, fortified milk
- Vitamin E: sunflower seeds, almonds
- Vitamin K: kale, spinach
[signup]
Key Takeaways
- The fecal steatocrit test is a diagnostic tool for diagnosing and managing fat malabsorption disorders.
- Its ability to provide direct and reliable measurements of stool fat content makes it invaluable in clinical practice. Through accurate diagnosis and ongoing monitoring, healthcare providers can tailor treatment strategies to improve patient outcomes.
- As research continues, advancements in testing methodologies and patient education will likely enhance the utility of fecal steatocrit in managing fat malabsorption disorders.
- For healthcare professionals and patients alike, understanding the role of fecal steatocrit in clinical practice is essential for effectively managing these complex conditions.
%201.svg){kind=logo}
