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Lab tests for Malabsorption
Malabsorption syndrome refers to a group of disorders characterized by the impaired absorption of nutrients in the gastrointestinal tract. There are various laboratory tests that can help in the diagnosis and evaluation of malabsorption syndrome. Here are some commonly used lab tests for malabsorption:
Blood tests can assess various parameters related to malabsorption, such as nutritional deficiencies, inflammation, and autoimmune markers. These lab tests for malabsorption may include:
- Complete blood count (CBC): It is a common blood test that provides information about the different components of blood, including red blood cells, white blood cells, and platelets. A CBC is often ordered as part of a routine health checkup or to help diagnose or monitor various medical conditions. For malabsorption, this test helps evaluate anemia or signs of infection.
- Serum albumin and total protein: Albumin is the most abundant protein in the blood and is primarily produced by the liver. It plays a crucial role in maintaining the oncotic pressure of blood, transporting various substances (such as hormones and drugs), and regulating fluid balance within the body. Low levels of serum albumin can indicate malnutrition, liver disease, kidney disease, inflammatory conditions, or chronic illnesses. Additionally, it can reflect inadequate protein intake or malabsorption. Total protein refers to the overall concentration of proteins in the blood, including albumin and other proteins. Low levels of these proteins may indicate malnutrition.
- Iron studies: To assess iron deficiency, including serum iron, ferritin, and total iron-binding capacity (TIBC).
- Vitamin B12 and folate levels: Deficiencies of these vitamins can contribute to malabsorption.
- Vitamin D and calcium levels: Malabsorption can lead to deficiencies in these nutrients. Vitamin D is a fat-soluble vitamin that plays a crucial role in calcium absorption and bone health. It is obtained through sun exposure, certain foods, and dietary supplements. Malabsorption can interfere with the absorption of vitamin D from the diet or reduce the body’s ability to produce active vitamin D from sunlight. When malabsorption affects vitamin D absorption, it can result in low levels of circulating vitamin D in the body, leading to vitamin D deficiency. Vitamin D deficiency can have various consequences, including weakened bones (osteoporosis or osteomalacia), increased risk of fractures, muscle weakness, impaired immune function, and potentially other health problems.
- C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR): These markers indicate inflammation in the body. CRP is a protein produced by the liver and elevated levels of CRP in the blood indicate the presence of inflammation in the body, but they do not specify the cause or location of the inflammation. ESR is a test that measures how quickly red blood cells settle in a tube of blood. When inflammation is present, certain proteins in the blood cause red blood cells to stick together and settle more rapidly. An elevated ESR is a nonspecific indicator of inflammation in the body. ESR is not specific to any particular condition but can help assess the presence and degree of inflammation.
- Autoimmune markers: Certain autoimmune conditions such as celiac disease, enteropathy, autoimmune gastritis, autoimmune pancreatitis etc can cause malabsorption, and specific antibody tests can help identify them.
Stool analysis provides valuable information about digestion, absorption, and presence of specific markers. These lab tests for malabsorption may include:
- Stool fat analysis: To determine the presence of excess fat in the stool, indicating fat malabsorption.
- Stool elastase: Assessing the level of pancreatic elastase can indicate pancreatic insufficiency.
- Stool Calprotectin: Calprotectin is a protein found in the stool that is released during inflammation in the gastrointestinal tract. Elevated levels of calprotectin may indicate inflammatory bowel disease (IBD) or other inflammatory conditions that can contribute to malabsorption.
- Stool cultures: To check for bacterial, parasitic, or fungal infections that may contribute to malabsorption.
- Stool pH: Stool pH refers to the acidity or alkalinity of the stool. Abnormal pH levels can be an indicator of malabsorption. For example, in conditions like carbohydrate malabsorption or bacterial overgrowth in the small intestine, there may be an increase in the production of acids or fermentation by-products, resulting in a lower pH.
Breath tests measure the amount of gases produced during the breakdown of certain substances. They can help diagnose specific types of malabsorption, such as lactose or fructose intolerance. Examples of breath lab tests for malabsorption include:
- Lactose breath test: This test is used to diagnose lactose intolerance, a condition where the body has difficulty digesting lactose, a sugar found in milk and dairy products. During the test, the individual consumes a lactose-containing drink, and breath samples are collected at regular intervals. If lactose is not properly absorbed in the small intestine, it reaches the colon where bacteria ferment it, producing gases such as hydrogen and methane. Elevated levels of these gases in the breath indicate lactose malabsorption.
- Glucose breath test: The glucose breath test is used to assess malabsorption of other carbohydrates, such as fructose or sorbitol. Similar to the lactose breath test, the individual consumes a test solution containing the specific carbohydrate, and breath samples are collected at intervals to measure the production of gases. Elevated levels of hydrogen or methane in the breath indicate malabsorption of the tested carbohydrate.
Small intestine biopsy
A biopsy involves the removal of a small tissue sample from the lining of the small intestine. It can help evaluate structural abnormalities, inflammation, or specific conditions like celiac disease.
It’s important to note that the specific lab tests for malabsorption ordered may vary depending on the suspected cause of malabsorption and the individual’s symptoms. Your healthcare provider will determine which tests are most appropriate for your situation.