Malabsorption

Malabsorption is a disorder in which sufferers struggle to digest foods or absorb their nutrients. This condition occurs in many different diseases. It can cause sufferers to become generally malnourished or deficient in essential nutrients.

Lab testing is used to evaluate individuals at a higher risk for malabsorption on account of a condition they suffer from, find the root causes, and determine the type and extent of nutritional deficiencies and possible complications, like anemia. Order the malabsorption test to evaluate individuals for malabsorption syndrome and bile acid malabsorption to find the root cause.

Lab tests are used to look at the condition of cells, organs, and the digestive system. They are used to search for a cause for primary symptoms, such as chronic diarrhea, which is one of the most common malabsorption symptoms that rule out any diseases linked with malabsorption. Tests can also find deficiencies and potential complications.

SEE BELOW THE LIST OF TESTS FOR MORE INFORMATION ABOUT Malabsorption


Name Matches
An increase in serum bile acids concentration in the fasting state or postprandial is considered to be a specific indicator of liver disease. A decreased level indicates bile acid malabsorption, possibly due to ileal dysfunction.

 Specimens from children less than 4 years of age (i.e., less than 48 months) are not appropriate for this test. The test for children 4 years of age and younger is the Celiac Disease Comprehensive Panel, Infant (test code 15981).

Includes

Tissue Transglutaminase, IgA with Reflexes; Total IgA with Reflex

IMPORTANT - Note this is Reflex Test which if additional tests are run you will be charged for the specific tests that the lab peforms. Additional test will be run if the following criteria are met.


If the Tissue Transglutaminase IgA is positive,

1. Endomysial Antibody Screen (IgA) will be performed at an additional charge (CPT code(s): 86255).

If the Endomysial Antibody Screen (IgA) is positive, 

2. Endomysial Antibody Titer will be performed at an additional charge (CPT code(s): 86256).

If the Total IgA is less than the lower limit of the reference range, based on age

3. Tissue Transglutaminase IgG will be performed at an additional charge (CPT code(s): 83516).

Clinical Significance

Celiac disease is caused by an immune response to gluten in genetically sensitive individuals. The diagnosis is largely based on a biopsy of the small intestine, but serologic tests also help support a diagnosis and may assist identification of patients who may require biopsy.

Tissue transglutaminase antibodies (tTG, IgA) is a marker with 95% sensitivity and specificity. Total IgA is measured because 2-3% of celiac disease patients are IgA deficient. Because tTG, IgA, and anti-Gliadin IgA tend to decrease in patients on a gluten-free diet, these markers are also used to assess dietary compliance.

The endomysial antibody (EMA, IgA) assay has high specificity for celiac disease and is used to confirm positive anti-tTG results.


Most Popular
Decreased levels of ceruloplasmin are found in Wilson''s Disease, fulminant liver failure, intestinal malabsorption, renal failure resulting in proteinuria, chronic active hepatitis and malnutrition. Elevated levels are found in primary biliary cirrhosis, pregnancy (first trimester), oral contraceptive use and in acute inflammatory conditions since ceruloplasmin is an acute phase reactant

A Complete Blood Count (CBC) Panel is used as a screening test for various disease states including anemia, leukemia and inflammatory processes.

A CBC blood test includes the following biomarkers: WBC, RBC, Hemoglobin, Hematocrit, MCV, MCH, MCHC, RDW, Platelet count, Neutrophils, Lymphs, Monocytes, Eos, Basos, Neutrophils (Absolute), Lymphs (Absolute), Monocytes(Absolute), Eos (Absolute), Basos (Absolute), Immature Granulocytes, Immature Grans (Abs)


See individual tests

Most Popular
Copper is an essential element that is a cofactor of many enzymes. Copper metabolism is disturbed in Wilson's disease, Menkes disease, primary biliary cirrhosis, and Indian childhood cirrhosis. Copper concentrations increase in acute phase reactions and during the third trimester of pregnancy. Copper concentrations are decreased with nephrosis, malabsorption, and malnutrition. Copper concentrations are also useful to monitor patients, especially preterm newborns, on nutritional supplementation. Results of copper are often interpreted together with ceruloplasmin.

Clinical Significance

Copper is an essential element that is a cofactor of many enzymes. Copper metabolism is disturbed in Wilson's disease, Menkes disease, primary biliary cirrhosis, and Indian childhood cirrhosis. Copper concentrations increase in acute phase reactions. Copper concentrations are decreased with nephrosis, malabsorption, and malnutrition. Copper concentrations are also useful to monitor patients, especially preterm newborns, on nutritional supplementation. Results of copper are often interpreted together with ceruloplasmin.


This test will identify approximately 90% of Cystic Fibrosis (CF) mutations in the Caucasian population, and 97% in the Ashkenazi Jewish population. For prenatal specimens, use test code 10226.

Vitamin D (distinct from the vitamin D metabolites, 25-hydroxyvitamin D or 1, 25 dihydroxyvitamin D) is an essential nutrient obtained via exposure to sunlight (cholecalciferol) or diet (ergocalciferol). Measuring the vitamin D cholecalciferol and ergocalciferol can be used in the diagnosis and management of disorders of fat absorption such as Crohn's Disease.

IMPORTANT - Requires a Prescription for 50,000 UNITS VITAMIN D2 to conduct this test that is not part of this test.


Fatty Acid Profile, Comprehensive


Fatty Acid Profile, Essential (C12-C22)


The fecal occult blood test is an immunochromatographic fecal occult blood test that qualitatively detects human hemoglobin from blood in fecal samples. This is a useful screening aid for detecting primarily lower gastrointestinal (G.I.) disorders that may be related to iron deficiency anemia, diverticulitis, ulcerative colitis, polyps, adenomas, colorectal cancers or other G.I. lesions that can bleed. It is recommended for use by health professionals as part of routine physical examinations and in screening for colorectal cancer or other sources of lower G.I. bleeding.

Most Popular

Immunoglobulin A (IgA)

Test Highlight

 

   

Clinical Use

  • Diagnose IgA deficiencies

  • Determine etiology of recurrent infections

  • Diagnose infection

  • Diagnose inflammation

  • Diagnose IgA monoclonal gammopathy

Clinical Background

IgA is the first line of defense for the majority of infections at mucosal surfaces and consists of 2 subclasses. IgA1 is the dominant subclass, accounting for 80% to 90% of total serum IgA and greater than half of the IgA in secretions such as milk, saliva, and tears. IgA2, on the other hand, is more concentrated in secretions than in blood. IgA2 is more resistant to proteolytic cleavage and may be more functionally active than IgA1.

IgA deficiency is the most prevalent isotype deficiency, occurring in 1/400 to 1/700 individuals. Many patients with IgA deficiency are asymptomatic, while others may develop allergic disease, repeated sinopulmonary or gastroenterologic infections, and/or autoimmune disease. Individuals with complete absence of IgA (<5 mg/dL) may develop autoantibodies to IgA after blood or intravenous immunoglobulin infusions and may experience anaphylaxis on repeat exposure. 

Elevated serum IgA levels are associated with infection, inflammation, or IgA monoclonal gammopathy.

 

The methylmalonic acid (MMA) test may be used to help diagnose an early or mild vitamin B12 deficiency. It may be ordered by itself or along with a homocysteine test as a follow-up to a vitamin B12 test result that is in the lower end of the normal range.


The Nonesterified Fatty Acids (Free Fatty Acids) assay is useful in evaluating lipolysis and fatty acid oxidation. Nonesterified Fatty Acids may be useful in evaluating patients with hypoglycemia and for nutritional assessment.



Most Popular
Prealbumin is decreased in protein-calorie malnutrition, liver disease, and acute inflammation. It may be used as an indicator of nutritional requirements and response to therapy during total parenteral nutrition and as a biochemical marker of nutritional adequacy in premature infants.

Screening test for abnormalities of coagulation factors that are involved in the extrinsic pathway. Also used to monitor effects of Warfarin therapy and to study patients with hereditary and acquired clotting disorders.

The presence of reducing substances is useful in the diagnosis of abnormalities in carbohydrate metabolism, i.e., sucrose and lactase. The unabsorbed sugars in stool are measured as reducing substances.


Useful in differentiating inflammatory and neoplastic diseases and as an index of disease severity. CRP is also useful in monitoring inflammatory disease states.

Most Popular

The Thyroid-stimulating Hormone (TSH) Blood Test is for differential diagnosis of primary, secondary, and tertiary hypothyroidism. The TSH test is also useful in screening for hyperthyroidism. This assay allows adjustment of exogenous thyroxine dosage in hypothyroid patients and in patients on suppressive thyroxine therapy for thyroid neoplasia.


Clinical Significance

Peroxisomes play a vital role in several metabolic pathways, including the synthesis of plasmalogens and bile acids. They are also involved in the catabolism of Very Long Chain Fatty Acids (VLCFAs), phytanic acid, and pristanic acid. Defects in these pathways usually result in the accumulation in tissues and body fluids of one or more metabolites derived from the blocked metabolic steps. Specific accumulations are used for the differential biochemical diagnosis of numerous peroxisomal disorders. These disorders include (A) Zellweger spectrum disorders of peroxisomal biogenesis, (B) X-linked adrenoleukodystrophy (X-ALD) and its adult form X-linked adrenomyeloneuropathy (X-AMN), (C) Refsum disease (Phytanoyl-CoA hydroxylase Deficiency), and (D) 2-methylacyl-CoA racemase deficiency.

Patient Preparation 

Avoid alcohol for 24 hours prior to collection. Draw sample in the morning following overnight fasting (12-14 hours)


Most Popular
Vitamin A is critical for vision, growth, and many cell functions. High concentrations of vitamin A are seen with renal failure, but this is not associated with toxicity, and excessive ingestion. High concentrations are associated with bone fractures. Low concentrations of vitamin A are consistent with fat malabsorption and rarely due to inadequate diet. Vitamin A, vitamin E, and carotene are always extracted and detected simultaneously. This is a free vitamin A (retinol

Vitamin B12 is decreased in pernicious anemia, total or partial gastrectomy, malabsorption and certain congenital and biochemical disorders



Malabsorption is a disorder in which sufferers struggle to digest foods or absorb their nutrients. This condition occurs in many different diseases. It can cause sufferers to become generally malnourished or deficient in essential nutrients.

For the body to function, it needs nutrients that allow it to maintain and repair itself. Nutrients are also used to produce energy and fight off infections. There are many essential vitamins and minerals that people derive from their diet.

When we eat food, it goes through three stages of digestion.

The fats, proteins, and complex sugars that we eat are broken down by the acids in our stomach, bile from our livers, and enzymes from our pancreas. When these nutrients are broken down, micronutrients are released.

The cells around our small intestines absorb most of the nutrients we eat.

From there, these nutrients travel throughout the body, where they used or stored for later.

If this process is halted in any way, malabsorption can occur. The seriousness of this issue and the symptoms that it causes can vary based on several factors. Is the disorder inhibiting the body’s ability to digest food? Which nutrients is the body struggling to digest?

Digestive Issues

Enzymes from the pancreas and bile are both required to correctly digest proteins, fats, and carbohydrates. If the liver or pancreas is diseased, it could inhibit the body’s ability to produce these substances. This can also occur in patients that suffer from cystic fibrosis. Enzymes from the pancreas may struggle to reach the body’s digestive tract.

Issues With Absorption

When the intestines cannot properly absorb nutrients, these nutrients are expelled from the body through bowel movements. This may occur when the tissue or cells of the intestine has been damaged in some way. This can also happen when the intestine has been shortened it some way, which could happen after surgery. This reduces the intestine surface area, which means there is less time for the body to absorb nutrients from food as it moves throughout the digestive tract.

For the body to absorb vitamin B12, it needs acid from the stomach as well as a substance called intrinsic factor, which is made by the stomach’s parietal cells. Acid from the stomach causes B12 to separate from proteins, which allows the intrinsic factor and the B12 to bind. If either stomach acids or intrinsic factor is not present, B12 cannot be absorbed by the intestines, which can cause a deficiency in vitamin B12. This may occur as people grow older. Several medications can cause less stomach acid to be produced. This issue may also occur after gastric bypass surgery if someone has a disorder that has caused damage to their parietal cells, or in patients that are suffering from general malabsorption.

Issues With Transport

After nutrients have been absorbed, they are transported through the body by cells. In some cases, transport problems may occur. This may happen in patients that are experiencing issues with their lymphatic system, which can be caused by lymphoma or abetalipoproteinemia, which is a rare hereditary disorder.

Malabsorption And Its Causes

Many disorders and diseases that can lead to malabsorption. These are just a few examples:

  • Cancers, such as stomach cancer, pancreatic cancer, or lymphoma
  • Conditions that cause the bile ducts to close, narrow, or disappear like biliary atresia, or block bile flow, like cholestasis, which leaves the body with insufficient bile for digestion
  • Celiac disease, a type of autoimmune disease that causes the lining of the intestines to be damaged
  • Intestinal damage, like the damage that can occur during radiation treatment
  • Cystic fibrosis, a hereditary disorder that can impact the pancreas and make it more difficult for enzymes from the pancreas to be transported through the body
  • A decrease in the production of intrinsic factor
  • Disorders that make it more difficult for the body to circulate throughout the body, like heart disease
  • Enzyme deficiencies, or intolerances to foods, like lactose intolerance
  • Hyperthyroidism
  • AIDS
  • Digestive tract infections, such as parasitic, bacterial, and viral infections
  • Inflammatory bowel diseases, such as ulcerative colitis or Crohn’s disease
  • Medications that inhibit the production of stomach acid, like phenytoin
  • Liver disease
  • Pancreatic disease or insufficiency, which can cause the amounts of enzymes the pancreas produces to be decreased
  • Certain types of surgeries, like gastric bypass or bowel resection s
  • Scleroderma
  • Zollinger-Ellison syndrome, a rare disorder that causes tumors to develop on the intestines or pancreas

Symptoms Of Malabsorption

The symptoms of a patient with malabsorption can vary based on the root cause of their condition. The type of nutrient someone is deficient in and the extent of the deficiency. The signs may be severe immediately, or they may gradually get worse in time. The body stores certain nutrients, like vitamin B12. Because of this, symptoms of deficiency will only become apparent after stores have been depleted. This is also true of pancreatic enzyme deficiency. Symptoms may not show until approximately 90% of the production capacity in the body has been halted.

A few of the symptoms that are most associated with general malabsorption are:

  • Chronic diarrhea
  • Steatorrhea, which causes bulky and oily stools with a strong odor
  • Children may be diagnosed with failure to thrive.
  • Cramps, gas, bloating, and general abdominal pain.

Many symptoms may be caused by nutritional deficiencies or by poor health. Some of these symptoms are:

  • Fatigue
  • Ascites, which causes a build-up of fluid in the abdomen
  • Rashes or dry and scaly skin
  • Glossitis, which is inflammation of the tongue
  • Unexplained weight loss or decrease in muscle mass
  • Nausea
  • Accumulation of fluid in the feet, legs, and hands
  • Mouth inflammation
  • Gum disease
  • Paleness
  • Tingling or a number feeling in the hands or feet.
  • Pain in the muscles or bones
  • Issues that can occur when someone suffers from chronic malabsorption, include:
  • Iron deficiency (anemia)
  • Confusion or difficulty concentrate
  • Failure to grow or develop in children
  • Osteoporosis
  • Malnutrition
  • Deficiencies in key vitamins, like vitamins D, k, and A

Testing For Malabsorption

Testing is primarily done to:

Evaluate patients that may be at a higher risk for malabsorption on account of a condition they suffer from, like cystic fibrosis

Diagnose malabsorption, find the root causes, and determine the type and extent of nutritional deficiencies

Diagnose possible complications, like anemia

Determine how effective malabsorption treatment has been

While there are many tests that a doctor might order if they suspect malabsorption, there isn’t any single test that can provide a diagnosis. In most cases, when a professional is ordering tests, they will look at additional factors as well, such as medical and family history, symptoms, and the results of a general examination. In many cases, testing will be done in stages so that other possible causes can be ruled out before a doctor provides a diagnosis. Examples of tests that may be run include:

Typically, the first set of tests will look at the condition of cells, organs, and the digestive system. From there, healthcare providers will search for a cause for primary symptoms, such as chronic diarrhea, which is one of the most common malabsorption symptoms.

After that, follow-up tests may be ordered to find or rule out any diseases that are linked with malabsorption. Tests can also find deficiencies and potential complications.

Lab Tests

Common initial tests are:

Complete blood count: Evaluates red blood cells and checks for anemia, which can be caused by B12, folate, or iron deficiency.

Comprehensive metabolic panel: Detects electrolyte imbalances, evaluates proteins, and function of various organs, like the liver.

Prealbumin: Checks for protein malabsorption and can provide information about general nutritional deficiency

Erythrocyte sedimentation rate: Detects bodily inflammation, which can be caused by conditions like inflammatory bowel disease

Fecal fat testing: To see if the body is properly digesting fat

Stool culture: Used to check for bacterial infection

Diff toxin and Clostridium difficile testing: Checks for bacterial overgrowth, which can cause chronic diarrhea

Ova and parasite examination: Checks for parasites, which can cause chronic diarrhea

White blood cells in stool: Can be found in patients suffering from certain inflammatory intestinal conditions

Gastrointestinal pathogen testing: Looks for bacteria, parasites, and viruses in the stool, which can cause both diarrhea and infections of the digestive tract

Thyroid-stimulating hormone: Identifies or eliminated thyroid disease

After the initial round of tests, healthcare practitioners will look at those results as well as the information from examinations and order additional tests. Examples of tests that may be ordered include:

Fecal occult blood test: Looks for digestive tract bleeding

Testing for deficiency in vitamins like AB12and D

Prothrombin time: Tests for deficiency in vitamin K

Celiac disease testing

Celiac disease testing, such as trypsinogen, CF gene mutation panels, and sweat tests

Tests that evaluate the pancreatic function, like stool trypsin, fecal elastase, and blood tests

Other tests that may be ordered are:

Hydrogen breath test: Can identify digestive system bacterial overgrowth and lactose intolerance

Methylmalonic Acid: Can detect vitamin B12 deficiency before signs are shown

Xylose absorption test: Carbohydrate digestive testing

Lactose tolerance test: This test, which can be used when testing for lactose intolerance, can also be used when diagnosis malabsorption