Diarrhea Lab Testing and health information

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Beta Carotene, a fat soluble nutrient, is a precursor to vitamin A. Deficiencies may lead to vitamin A deficiency. Excessive vitamin A intake may lead to headaches, loss of appetite, nausea and diarrhea, skin changes, and potential birth defects.

C. difficile is the major cause of antibiotic-associated diarrhea (AAD) and pseudomembranous colitis.

Additional Charge Possible: If the GDH Antigen is detected and the Toxin A and B are not detected or the GDH Antigen is not detected and the Toxin A and B are detected, Clostridium difficile Toxin B, Qualitative, Real-Time PCR will be performed at an additional charge.

After treatment with antibiotics, many patients develop gastrointestinal problems ranging from mild diarrhea to severe pseudomembranous colitis. This organism is an opportunistic anaerobic bacterium that grows in the intestine once the normal flora has been altered by the antibiotic. For diagnosis of toxigenic C. difficile, current practice guidelines from the CDC recommend confirmation by Nucleic Acid Amplification Testing (NAAT) if the glutamate dehydrogenase of C. difficile (GDH) Antigen is positive, and toxin is not detected by Enzyme immunoassay. Additionally, if toxin is detected without the presence of GDH antigen, confirmation by NAAT is also recommended.

Rotavirus infection is the major cause of gastroenteritis in children from six months to two years. Infection occurs in both sporadic and epidemic forms and is responsible for approximately half the cases of diarrhea in infants that require hospitalization worldwide. The peak of rotavirus disease in temperate climates occurs during the cooler months of the year. Rotavirus has also emerged as a cause of enteritis in adults, particularly in elderly immunosuppressed patients.

Description: Fecal Globulin by immunochemistry is a test that measures the amount of blood present in fecal samples. The results from the fecal globulin test can be used to detect a lower gastrointestinal disorder. It is recommended to be a part of the routine physical examination.

Also Known As: Fecal Immunochemical Test, Fecal Occult Blood Test, Stool Occult Blood Test, FIT, FOBT

Collection Method: Fecal specimen collected from toilet water and brushed onto InSure® FOBT test card

Specimen Type: Fecal Specimen

Test Preparation: No preparation required

When is a Fecal Globin test ordered?

When a person chooses fecal occult blood testing as a method of colon cancer screening, the American Cancer Society and other major healthcare organizations recommend yearly testing. The American Cancer Society and others recommend that colon cancer screening begin around age 50 for the general population, but it may begin earlier if a person has a family history of colon cancer.

An FOBT may be ordered by a doctor if a patient has unexplained anemia that could be caused by gastrointestinal bleeding.

What does a Fecal Globin test check for?

The majority of colon cancer cases begin with the formation of benign intestinal polyps. Benign polyps are quite common in adults over 50, and while the majority do not cause health problems, some can turn malignant and spread to other parts of the body. These finger-like growths protrude into the rectum or the intestinal cavity. They can be delicate and bleed on occasion, as when food debris rubs against them.

The blood expelled is normally not visible in the stool, but a fecal occult blood test or a fecal immunochemical test can detect it. The FOBT and FIT are effective colorectal cancer screening techniques because this small amount of blood may be the earliest and sometimes only evidence of early colon cancer. A guaiac-based test, an over-the-counter flushable reagent pad, and an immunochemical technique are all options for testing.

It is advised that at least three stool samples be taken on different days be tested. According to the American Cancer Society, a single test performed during a digital rectal exam at a doctor's office is not recommended since it may not be sensitive enough to detect cancer. Because collecting feces on three different days increases the chances of identifying cancer, the home FOBT or FIT is advised. Additionally, those who choose this type of colon cancer screening should be screened every year.

Lab tests often ordered with a Fecal Globin test:

  • Complete Blood Count (CBC)
  • Calprotectin

Conditions where a Fecal Globin test is recommended:

  • Colon Cancer

How does my health care provider use a Fecal Globin test?

The fecal occult blood test, also known as the fecal immunochemical test, is primarily used to screen for early colon cancer. The majority of colon cancer cases begin with the formation of benign intestinal polyps. People over the age of 50 are more likely to develop benign polyps. The majority are non-cancerous, however some can develop malignant.

Blood in the stool could be the only sign of early cancer, so if caught early, therapy can begin right away, increasing the chances of a cure.

What do my Fecal Occult Blood test results mean?

Normally, the fecal occult blood test is negative.

A positive test result for the guaiac-based FOBT shows that abnormal bleeding is occurring anywhere in the digestive tract. Ulcers, diverticulosis, polyps, inflammatory bowel disease, hemorrhoids, blood eaten owing to bleeding gums or nosebleeds, or benign or malignant tumors could all cause blood loss.

A positive result for the fecal immunochemical test shows abnormal bleeding in the lower digestive tract. Other sources of blood, such as those found in the diet, do not generate a positive result since this test only identifies human hemoglobin. Furthermore, hemoglobin from upper digestive tract hemorrhage is broken down before reaching the lower digestive tract and is undetectable by the FIT. As a result, the FIT is a more precise test than the gFOBT.

Follow-up testing is required after a positive result from either the guaiac-based FOBT or the immunochemical FIT. Direct imaging of the colon and rectum is generally used.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.

Detection of antibodies to gliadin, one of the major protein components of gluten, is a sensitive assay useful in diagnosing celiac disease. However, gliadin antibodies may be found in individuals without celiac disease; thus gliadin antibody assays are less specific than assays measuring antibodies to endomysium and transglutaminase. Recent work has revealed that gliadin-reactive antibodies from celiac patients bind to a very limited number of specific epitopes on the gliadin molecule. Further, deamidation of gliadin results in enhanced binding of gliadin antibodies. Based on this information, assays using deamidated gliadin peptides bearing the celiac-specific epitopes have much higher diagnostic accuracy for celiac disease when compared to standard gliadin antibody assays.

Detection of antibodies to gliadin, one of the major protein components of gluten, is a sensitive assay useful in diagnosing celiac disease. However, gliadin antibodies may be found in individuals without celiac disease; thus gliadin antibody assays are less specific than assays measuring antibodies to endomysium and transglutaminase. Recent work has revealed that gliadin-reactive antibodies from celiac patients bind to a very limited number of specific epitopes on the gliadin molecule. Further, deamidation of gliadin results in enhanced binding of gliadin antibodies. Based on this information, assays using deamidated gliadin peptides bearing the celiac-specific epitopes have much higher diagnostic accuracy for celiac disease when compared to standard gliadin antibody assays.

Detection of antibodies to gliadin, one of the major protein components of gluten, is a sensitive assay useful in diagnosing celiac disease. However, gliadin antibodies may be found in individuals without celiac disease; thus gliadin antibody assays are less specific than assays measuring antibodies to endomysium and transglutaminase. Recent work has revealed that gliadin-reactive antibodies from celiac patients bind to a very limited number of specific epitopes on the gliadin molecule. Further, deamidation of gliadin results in enhanced binding of gliadin antibodies. Based on this information, assays using deamidated gliadin peptides bearing the celiac-specific epitopes have much higher diagnostic accuracy for celiac disease when compared to standard gliadin antibody assays.

The Lactoferrin IBD-CHEK® is a qualitative (QL) Enzyme Linked Immunosorbent Assay (ELISA) for measuring concentrations of fecal lactoferrin, a marker for leukocytes. A positive level is an indicator of intestinal inflammation. The test can be used as an in vitro diagnostic aid to distinguish patients with active inflammatory bowel disease (IBD) from those with non inflammatory irritable bowel syndrome (IBS).

Clinical Significance

Used to diagnose inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, or to differentiate IBD from irritable bowel syndrome (IBS).


Collection Instructions

Collect undiluted feces in clean, dry sterile leak-proof container. Do not add fixative or preservative.


The QuantaLite™ ASCA (S. cerevisiae) IgG kit is an Enzyme-Linked Immunosorbent Assay (ELISA) for the semi-quantitative detection of anti-saccharomyces cerevisiae antibodies (ASCA) of the IgG class in human serum. This test is intended to aid in the diagnosis of patients with Crohn's disease.

5-Hydroxyindoleacetic Acid (5-HIAA), 24-Hour Urine, with Creatinine

Patient Preparation: Patient should avoid food high in indoles: avocado, banana, tomato, plum, walnut, pineapple, and eggplant.

Collection Instructions : Collect 24-hour urine with 6N HCL to maintain a pH below 3. Urine without preservative is acceptable if pH is below 6 and the sample is shipped frozen. Keep urine refrigerated during collection if preservative is not used. Shipping refrigerated acceptable, shipping frozen acceptable. Record 24-hour urine volume on test request form and urine vial. Record patient's age on test request form and urine vial.

Clinical Significance: 5-HIAA is the end product of serotonin (5-hydroxytryptophan) and tyrptophan metabolism. Patients with carcinoid tumors of the midgut, e.g., ileum, produce high concentrations of 5-HIAA. Patients with carcinoid tumors of the foregut and hindgut may produce little or no 5-HIAA or do so intermittently.

Limitations: Patients with renal disease may display falsely decreased results. Urinary 5-HIAA is increased in patients with malabsorption disorders who also display a larger concentration of urinary tryptophan metabolites. Urinary 5-HIAA is increased in patients with intestinal obstruction and with some noncarcinoid islet cell tumors. Carcinoid syndrome may not cause elevated results, especially if the patient does not have diarrhea.

Description: A Comprehensive Metabolic Panel or CMP is a blood test that is a combination of a Basic Metabolic Panel, a Liver Panel, and electrolyte panel, and is used to screen for, diagnose, and monitor a variety of conditions and diseases such as liver disease, diabetes, and kidney disease. 

Also Known As: CMP, Chem, Chem-14, Chem-12, Chem-21, Chemistry Panel, Chem Panel, Chem Screen, Chemistry Screen, SMA 12, SMA 20, SMA 21, SMAC, Chem test

Collection Method: 

Blood Draw 

Specimen Type: 


Test Preparation: 

9-12 hours fasting is preferred. 

When is a Comprehensive Metabolic Panel test ordered:  

A CMP is frequently requested as part of a lab test for a medical evaluation or yearly physical. A CMP test consists of many different tests that give healthcare providers a range of information about your health, including liver and kidney function, electrolyte balance, and blood sugar levels. To confirm or rule out a suspected diagnosis, abnormal test results are frequently followed up with other tests that provide a more in depth or targeted analysis of key areas that need investigating. 

What does a Comprehensive Metabolic Panel blood test check for? 

The complete metabolic panel (CMP) is a set of 20 tests that provides critical information to a healthcare professional about a person's current metabolic status, check for liver or kidney disease, electrolyte and acid/base balance, and blood glucose and blood protein levels. Abnormal results, particularly when they are combined, can suggest a problem that needs to be addressed. 

The following tests are included in the CMP: 

  • Albumin: this is a measure of Albumin levels in your blood. Albumin is a protein made by the liver that is responsible for many vital roles including transporting nutrients throughout the body and preventing fluid from leaking out of blood vessels. 

  • Albumin/Globulin Ratio: this is a ratio between your total Albumin and Globulin  

  • Alkaline Phosphatase: this is a measure of Alkaline phosphatase or ALP in your blood. Alkaline phosphatase is a protein found in all body tissues, however the ALP found in blood comes from the liver and bones. Elevated levels are often associated with liver damage, gallbladder disease, or bone disorder. 

  • Alt: this is a measure of Alanine transaminase or ALT in your blood. Alanine Aminotransferase is an enzyme found in the highest amounts in the liver with small amounts in the heart and muscles. Elevated levels are often associated with liver damage. 

  • AST: this is a measure of Aspartate Aminotransferase or AST. Aspartate Aminotransferase is an enzyme found mostly in the heart and liver, with smaller amounts in the kidney and muscles. Elevated levels are often associated with liver damage. 

  • Bilirubin, Total: this is a measure of bilirubin in your blood. Bilirubin is an orange-yellowish waste product produced from the breakdown of heme which is a component of hemoglobin found in red blood cells. The liver is responsible for removal of bilirubin from the body. 

  • Bun/Creatinine Ratio: this is a ratio between your Urea Nitrogen (BUN) result and Creatinine result.  

  • Calcium: this is a measurement of calcium in your blood. Calcium is the most abundant and one of the most important minerals in the body as it essential for proper nerve, muscle, and heart function. 

  • Calcium: is used for blood clot formation and the formation and maintenance of bones and teeth. 

  • Carbon Dioxide: this is a measure of carbon dioxide in your blood. Carbon dioxide is a negatively charged electrolyte that works with other electrolytes such as chloride, potassium, and sodium to regulate the body’s acid-base balance and fluid levels.  

  • Chloride: this is a measure of Chloride in your blood. Chloride is a negatively charged electrolyte that works with other electrolytes such as potassium and sodium to regulate the body’s acid-base balance and fluid levels. 

  • Creatinine: this is a measure of Creatinine levels in your blood. Creatinine is created from the breakdown of creatine in your muscles and is removed from your body by the kidneys. Elevated creatinine levels are often associated with kidney damage. 

  • Egfr African American: this is a measure of how well your kidneys are functioning. Glomeruli are tiny filters in your kidneys that filter out waste products from your blood for removal while retaining important substances such as nutrients and blood cells. 

  • Egfr Non-Afr. American: this is a measure of how well your kidneys are functioning. Glomeruli are tiny filters in your kidneys that filter out waste products from your blood for removal while retaining important substances such as nutrients and blood cells. 

  • Globulin: this is a measure of all blood proteins in your blood that are not albumin. 

  • Glucose: this is a measure of glucose in your blood. Glucose is created from the breakdown of carbohydrates during digestion and is the body’s primary source of energy. 

  • Potassium: this is a measure of Potassium in your blood. Potassium is an electrolyte that plays a vital role in cell metabolism, nerve and muscle function, and transport of nutrients into cells and removal of wastes products out of cells. 

  • Protein, Total: this is a measure of total protein levels in your blood. 
    Sodium: this is a measure of Sodium in your blood. Sodium is an electrolyte that plays a vital role in nerve and muscle function. 

  • Sodium: this is a measure of sodium in your blood's serum. Sodium is a vital mineral for nerve and muscle cell function.

  • Urea Nitrogen (Bun): this is a measure of Urea Nitrogen in your blood, also known as Blood UreaNitrogen (BUN). Urea is a waste product created in the liver when proteins are broken down into amino acids. Elevated levels are often associated with kidney damage. 

Lab tests often ordered with a Comprehensive Metabolic Panel test: 

  • Complete Blood Count with Differential and Platelets
  • Iron and Total Iron Binding Capacity
  • Lipid Panel
  • Vitamin B12 and Folate
  • Prothrombin with INR and Partial Thromboplastin Times
  • Sed Rate (ESR)
  • C-Reactive Protein

Conditions where a Comprehensive Metabolic Panel test is recommended: 

  • Diabetes
  • Kidney Disease
  • Liver Disease
  • Hypertension

Commonly Asked Questions: 

How does my health care provider use a Comprehensive Metabolic Panel test? 

The comprehensive metabolic panel (CMP) is a broad screening tool for assessing organ function and detecting diseases like diabetes, liver disease, and kidney disease. The CMP test may also be requested to monitor known disorders such as hypertension and to check for any renal or liver-related side effects in persons taking specific drugs. If a health practitioner wants to follow two or more separate CMP components, the full CMP might be ordered because it contains more information. 

What do my Comprehensive Metabolic Panel test results mean? 

The results of the tests included in the CMP are usually analyzed together to look for patterns. A single abnormal test result may indicate something different than a series of abnormal test findings. A high result on one of the liver enzyme tests, for example, is not the same as a high result on several liver enzyme tests. 

Several sets of CMPs, frequently performed on various days, may be examined to gain insights into the underlying disease and response to treatment, especially in hospitalized patients. 

Out-of-range findings for any of the CMP tests can be caused by a variety of illnesses, including kidney failure, breathing issues, and diabetes-related complications, to name a few. If any of the results are abnormal, one or more follow-up tests are usually ordered to help determine the reason and/or establish a diagnosis. 

Is there anything else I should know? 

A wide range of prescription and over-the-counter medications can have an impact on the results of the CMP's components. Any medications you're taking should be disclosed to your healthcare professional. Similarly, it is critical to provide a thorough history because many other circumstances can influence how your results are interpreted. 

What's the difference between the CMP and the BMP tests, and why would my doctor choose one over the other? 

The CMP consists of 14 tests, while the basic metabolic panel (BMP) is a subset of those with eight tests. The liver (ALP, ALT, AST, and bilirubin) and protein (albumin and total protein) tests are not included. If a healthcare provider wants a more thorough picture of a person's organ function or to check for specific illnesses like diabetes or liver or kidney disease, he or she may prescribe a CMP rather than a BMP. 

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.

Please note the following regarding BUN/Creatinine ratio: 

The lab does not report the calculation for the BUN/Creatinine Ratio unless one or both biomarkers’ results fall out of the published range. 

If you still wish to see the value, it's easy to calculate. Simply take your Urea Nitrogen (BUN) result and divide it by your Creatinine result.  

As an example, if your Urea Nitrogen result is 11 and your Creatinine result is 0.86, then you would divide 11 by 0.86 and get a BUN/Creatinine Ratio result of 12.79. 

Clinical Significance

Serum osmolality is increased in hypernatremia, hyperglycemia, uremia, ethanol, methanol, or ethylene glycol overdoses, and in diabetes insipidus.

Description: The electrolyte panel test is a blood test that measures levels of electrolytes in the blood’s serum.

Also Known As: Lytes Panel, Anion Gap Panel, Electrolyte Test, Lytes Test, Anion Gap Test

Collection Method: Blood Draw

Specimen Type: Serum

Test Preparation: No preparation required

When is an Electrolyte Panel test ordered?

An electrolyte panel may be requested as part of a regular screening or as a diagnostic tool when an individual symptoms, such as:

  • Accumulation of fluid
  • Weakness Nausea or vomiting
  • Confusion
  • Heartbeat irregularity

It is usually requested as part of an examination when a person has an acute or chronic illness, as well as at regular intervals when a person has a disease or condition, or is receiving medication that can induce an electrolyte imbalance. Electrolyte tests are frequently requested at regular intervals to evaluate the therapy of disorders such as high blood pressure, heart failure, lung ailments, and liver and kidney disease.

What does an Electrolyte Panel test check for?

Electrolytes are minerals that are found as dissolved salts in bodily tissues and blood. Electrolytes help transfer nutrients into and waste out of the body's cells, maintain a healthy water balance, and control the body's acid/base level as electrically charged particles.

The electrolyte panel determines the concentrations of sodium, potassium, chloride, and bicarbonate in the blood.

Sodium, potassium, and chloride are all found in a person's diet. By reabsorption or disposal into the urine, the kidneys assist in maintaining correct levels. The lungs regulate CO2 and provide oxygen. The body produces CO2, which is balanced with bicarbonate. The total balance of these substances is a sign of how well various essential biological functions are working. They play a role in a variety of biological activities, including cardiac and skeletal muscle contraction, as well as nerve impulse conduction.

A fluid, electrolyte, or pH imbalance can be caused by any disease or condition that changes the volume of fluid in the body, such as dehydration, or affects the lungs, kidneys, metabolism, or respiration. To ensure the appropriate functioning of metabolic processes and the supply of the right quantity of oxygen to tissues, normal pH must be maintained within a limited range of 7.35-7.45 and electrolytes must be in balance.

The anion gap, which is a value calculated from the results of an electrolyte panel, is a related "test." It indicates the difference in charge between positively and negatively charged ions. Although an aberrant anion gap is non-specific, it can indicate the presence of hazardous chemicals or metabolic or respiratory problems.

Lab tests often ordered with an Electrolyte Panel test:

  • Basic Metabolic Panel (BMP)
  • Comprehensive Metabolic Panel (CMP)
  • Creatinine
  • Glucose

Conditions where an Electrolyte Panel test is recommended:

  • Acidosis
  • Alkalosis
  • Kidney Disease
  • Hypertension
  • Dehydration
  • Congestive Heart Failure

How does my health care provider use an Electrolyte Panel test?

An electrolyte, fluid, or pH imbalance is detected using the electrolyte panel. It's commonly ordered as part of a normal physical examination. It is available as a standalone test or as part of a basic or comprehensive metabolic panel. Other tests like as BUN, creatinine, and glucose may be included in these panels.

Electrolyte measures can be used to assess illnesses including dehydration, kidney disease, lung disease, or heart disease that induce electrolyte imbalances. Repeat testing can then be performed to track the progress of treatment for the ailment that caused the imbalance.

Because electrolyte and acid-base imbalances can occur in a wide range of acute and chronic disorders, the electrolyte panel is commonly used to assess patients in both the emergency room and the hospital.

The electrolyte panel includes tests for the following electrolytes:

  • Sodium—the majority of sodium in the body is located in extracellular fluid, which is situated outside of cells and helps to regulate the quantity of water in the body.
  • Potassium is an electrolyte that is mostly present inside the body's cells. The plasma, or liquid portion of the blood, contains a modest but vital amount of potassium. Potassium levels must be monitored since even modest variations might alter the heart's rhythm and ability to contract.
  • Chloride—this electrolyte travels in and out of cells to assist maintain electrical neutrality, and its level is usually the same as sodium's.
  • Bicarbonate—the primary function of bicarbonate, which is produced and reabsorbed by the kidneys, is to maintain a constant pH level and, secondarily, to maintain electrical neutrality.

An anion gap calculation may be included in the electrolyte panel data.

If a person has an electrolyte imbalance, such as sodium or potassium, the health practitioner may prescribe additional testing of that specific electrolyte, as well as monitoring the imbalance until it resolves. If someone has an acid-base imbalance, a health care provider may prescribe blood gas tests, which measure the pH, oxygen, and carbon dioxide levels in an arterial blood sample to assist assess the severity of the problem and track its progress.

What do my electrolyte panel test results mean?

Several disorders and diseases can induce high or low electrolyte levels. They are often influenced by the amount of food taken and absorbed by the body, the amount of water in the body, and the amount excreted by the kidneys. They are also influenced by hormones like aldosterone, which conserves sodium while promoting potassium disposal, and natriuretic peptides, which stimulate sodium excretion via the kidneys.

People with malfunctioning kidneys, for example, may retain an excessive amount of water in their bodies. This has the effect of diluting sodium and chloride, lowering their quantities below normal. People who have lost a lot of fluid, on the other hand, may have higher potassium, sodium, and chloride levels. Some diseases, such as heart disease and diabetes, can disrupt the body's fluid and electrolyte balance, resulting in abnormal electrolyte levels.

Knowing which electrolytes are out of balance can assist a health care provider in determining the underlying cause and making treatment recommendations to restore appropriate balance. An electrolyte imbalance, if left untreated, can cause dizziness, cramping, irregular heartbeat, and even death.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.

Absolute Lymphocyte Count includes: WBC, Absolute Lymphocytes, % Lymphocytes, % Reactive Lymphocytes

Clinical Significance

Increased understanding of immunodeficiency syndrome and AIDS have identified the importance of absolute lymphocyte count in addition to the specific cell type such as CD4 lymphocytes. In pediatric ages up to 14 years old, acute infectious lymphocytosis is a clinical disorder, suspected to be of enterovirus-Coxsackie A subgroup that may have upper respiratory symptoms, fever, diarrhea and abdominal pain or a totally asymptomatic clinical course. Other conditions with absolute lymphocytosis are B. pertussis infection and lymphocytic leukemoid reaction. The most commonly known lymphocytosis with atypical morphology is due to cytomegalovirus and infectious mononucleosis. The malignant forms of absolute lymphocytosis are mostly due to lymphoproliferative disorders.

Adenovirus causes respiratory tract infections, conjunctivitis, and diarrhea. Infections are most common in individuals who are immunocompromised and in young children. Adenovirus Antigen Detection is useful to confirm the diagnosis of adenovirus infection in patients with gastroenteritis.

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For diagnosis of allergic disease. A normal IgE level does not exclude the possible presence of an allergic disorder.

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Increased IgG is associated with acute and chronic inflammations, monoclonal IgG myeloma, autoimmune diseases; decreased IgG is found in selective IgG deficiency, Bruton's Disease, and acquired immune deficiency.

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Increased IgM is associated with Waldenström's macroglobulinemia, infectious mononucleosis, viral infections, nephrotic syndrome, and estrogen therapy; decreased IgM is found in selective IgM deficiency, Bruton's Disease, and acquired immune deficiency.

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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.


Microsporidia infection was first recognized as a cause of chronic diarrhea in patients infected with HIV. Microsporidia may also cause pneumonia, acute bilateral keratoconjunctivitis, and infection of the biliary and pancreatic ducts.

Salmonella, Total Antibody, detects antibodies to Salmonella typhi, a common cause of gastroenteritis, diarrhea, and dysentery. Antibody results should be confirmed with stool or blood cultures

Diarrhea is indicative of a gastrointestinal ailment. It entails passing loose stool frequently that may be accompanied by cramping, stomach pain (especially in the abdomen), vomiting, nausea, and fatigue. In some cases, the stool may also contain mucus and or blood.

Acute Diarrhea lasts between one and a few days. Most adults tend to experience Diarrhea several times every year without complications. Such bouts of acute Diarrhea tend to clear themselves without needing any medical treatment. However, when a diarrhea bout lasts anywhere between two and four weeks, it is considered chronic. Chronic diarrhea cases can be persistent or intermittent over the period.

Chronic and severe Diarrhea tends to be very dangerous, especially among the elderly and young children. Severe and or persistent diarrhea bouts can cause electrolyte imbalance and dehydration. Among infants, Diarrhea can cause severe dehydration in as little as one or two days. Electrolyte imbalance can be life-threatening, whether there is too much or too little of electrolytes in the body. As such, some severe diarrhea cases necessitate hospitalization.

Common Causes Of Diarrhea

Numerous infectious and non-infectious causes cause acute and chronic diarrhea bouts.

Common Infectious Causes:

Bacterial, viral, and parasitic infections are known to cause Diarrhea that can last from a few days to weeks. In some cases of individuals with a suppressed immune system such (for instance, among patients with cancer, AIDs, or organ transplants), Diarrhea might linger, resulting in chronic Diarrhea. These causes of Diarrhea are infectious. The bacteria, virus, or parasite is shed into a person’s stool and then passed to other people via oral contact with any of the contaminated surfaces. The most common contamination method is consuming contaminated foods and water.

Once you get infected, you will pass on the infection to others around you, unless you follow high standards of sanitation, especially washing your hands. This tends to be a challenge for environments with young children (such as daycare centers) and in nursing homes. It does not take a lot to cause a bacterial or parasitic infection outbreak. It can arise from infected foods at a restaurant, picnic, or any other eatery outlet. In other cases, drinking contaminated water can result in an outbreak.

When traveling to other countries, especially emerging nations, you may be exposed to several disease-causing bacteria, viruses, and parasites. Something as simple as unwashed fruit, ice cubes, or food from vendors can expose to illness.


In the United States, Norovirus is the leading cause of acute gastroenteritis, the severe and or sudden illness of the digestive tract. Also called Norwalk-like virus, the Center for Disease Control and Prevention (CDC) says this virus is the leading cause of waterborne and food illnesses. The virus is very contagious, spreading from one person to another and can contaminate water and foods. There are many recorded cases of the norovirus outbreaks in cruise ships, schools, nursing homes, military bases, and other places with high human population concentration.

Rotavirus, on the other hand, is renowned for causing severe Diarrhea among young kids. Typically, the virus spread through contact with infected stool. To prevent the spread of this virus, you must wash your hands after every diaper change. Regularly clean the surface of all objects your kids come in contact with, including the changing table, toys, and much more. You can also give your infants an oral vaccine that has over 98% effectiveness in rotavirus infection prevention.

Other viruses that cause Diarrhea include Cytomegalovirus (CMV), Hepatitis A, and Adenoviruses.

Bacteria: Bacteria cause Diarrhea by producing toxins or infection.

In the case of infections, you ingest live bacteria. Once on the intestinal tract, they, later on, grow and multiply, causing Diarrhea. The most common types of bacteria responsible for Diarrhea include:

  • Salmonella, which is commonly found in raw poultry, raw eggs, and in pet reptiles. A salmonella infection will produce symptoms between 12 and 72 hours of ingesting the bacteria, and it can last between 4 and 7 days. Typically, a salmonella infection resolves without needing any treatment. However, among young children and the elderly, Diarrhea may become too severe, requiring hospitalization and antibiotic treatments. Salmonella serotype Typhimurium Enteritidis and Salmonella serotype in the U.S., especially among travelers.
  • Campylobacter. Commonly found in unpasteurized milk, cheese, under-cooked poultry, and in contaminated water. Campylobacter causes water and or bloody stools with symptoms arising 2 to 5 days after the infection. The illness lasts about one week. Supportive care is enough to overcome the disease, but in some cases, especially prolong illness cases, antibiotics treatment is necessary.
  • Yersinia species. These bacteria are commonly found in seafood, unpasteurized milk, and under-cooked pork. A Yersinia infection is associated with ‘chitlins,’ a delicacy cooked from hogs’ intestines and often prepared during holidays. As such, there tends to be an increase in the number of Yersinia infection cases during winter. Yersinia enterocolitica is the most common Yersinia species.
  • Vibrio species. It is typically found in raw oysters and contaminated seafood. Vibrio Cholerae is the bacteria that causes cholera. However, Vibrio parahaemolyticus is the most prevalent.

Some bacteria produce diarrhea-causing toxins. The most common of such bacteria include:

  • Staphylococcus aureus. This is a common bacterium typically found on the hair and skin, as well as the throats and noses of many people. It is responsible for many cases of food poisoning. The bacteria may contaminate food during preparation, and if the food is improperly cooked and or not refrigerated, there is a chance of getting food poisoning. The bacteria produce toxins that cause severe symptoms of vomiting, nausea, and Diarrhea in just a few hours after consuming the contaminated food.
  • Bacillus cereus. Bacillus cereus is found in many different foods, especially rice. It is also prevalent in leftover foods that have stayed at room temperature for long. Symptoms of poisoning include Diarrhea and cramps come about between 6 and 15 after consuming contaminated foods.
  • Clostridium difficile (C diff) diarrhea caused by Clostridium difficile’s toxins is indicative of antibiotic-related issues. Antibiotic treatment can destroy your gut flora by killing the good bacteria in the gastrointestinal tract. The good bacteria are beneficial to your overall health as they help digest food and protect against harmful bacteria. When you destroy the good bacteria, you make it easier for harmful bacteria such as C. difficile to grow, thrive, and multiply, which in turn causes Diarrhea.
  • Clostridium perfringens. This strain of bacteria is commonly found in poultry and raw meat. Ingesting poorly cooked and or poorly stored meat can cause a Clostridium perfringens infection. The bacteria have developed a mechanism to overcome harsh conditions such as high temperatures. For instance, it forms spores that resist high temperatures. After the cooked food cools down, the bacteria sprout again and begins to grow. When you ingest the bacteria, you get an acute infection characterized by Diarrhea and cramping (without vomiting and fever) within 8 to 12 hours. The symptoms last less than 24 hours.
  • Clostridium botulinum. These bacteria are responsible for botulism, a disease caused by improper handling of food during the canning process. The bacteria produce a toxin that results in Diarrhea, vomiting, muscle weakness, drooping eyelids, blurred and or double vision, dry mouth, difficulty swallowing, and slurred speech. When left untreated, the disease causes muscle paralysis, affecting the breathing system, arms, legs, and trunk. To prevent cases of foodborne botulism, you should follow the best practices in home-canning. Exposing the bacteria to high temperature is the best way to kill them.
  • Shigella. These bacteria stem from water and food contaminated with stool. Some of the Shigella species produce toxins that cause reactive arthritis, as well as a hemolytic uremic syndrome (HUS), an ailment associated with kidney failure, and the destruction of red blood cells. Additionally, some species, such as Shigella dysenteriae, cause fever, severe bloody Diarrhea, and dysentery.
  • Escherichia coli 0157:H7 (E. coli). Most humans and animals have E. coli in their digestive tract. However, the vast majority of E. coli strains do not cause harm. However, the STEC (Shiga toxin-producing E. coli) produce toxins in the form of Shiga toxin, which in turn leads to bloody Diarrhea. Serious E. coli infections are known to spread from undercooked meat such as hamburger. It also spread from person to person. Young children and the elderly some out worse when infected with E. coli owing to the severe nature of STEC-caused infections.

Parasites: Typical parasites that cause Diarrhea in the U.S. are:

  • Giardia species
  • Entamoeba histolytica
  • Cryptosporidium parvum

These parasites are commonly found in lakes and mountain streams. Additionally, they may also inhabit hot tubs, swimming pools. On rare occasions, they may find their way into water supplies.

Other parasites, including tapeworms and roundworms, can also cause infections.

In the warm parts of the world, especially in developing countries, pathogenic bacteria tend to be of greater range, and they frequently cause disease outbreaks. These include roundworms, hookworms, flatworms, and flukes. People get infected by ingesting food and drinks contaminated with ova (the parasite’s eggs). Some parasites are also capable of penetrating the skin.

The Non-Infectious Causes Of Diarrhea

Non-infectious causes typically cause chronic Diarrhea, Diarrhea that alternates with constipation, and sporadic Diarrhea.

Among these causes include:

  • Inflammatory bowel diseases, such as ulcerative colitis and Crohn’s disease
  • Bowel dysfunction, for instance, caused by irritable bowel syndrome
  • Colon polyps or cancer
  • Chemotherapy or gastrointestinal or abdominal radiation
  • Food sensitivities or intolerances, including celiac disease and lactose intolerance
  • Use of laxatives
  • Pancreatic diseases
  • Malabsorption disorders such as cystic fibrosis
  • Gallbladder or stomach surgery (the rate of food passage through the digestive system may change)
  • Endocrine diseases, including thyroid and diabetes disease
  • Carcinoid syndrome (a group of symptoms that include Diarrhea found among people with carcinoid tumors found in the colon, small intestine, or appendix)
  • Medication that causes Diarrhea as a side effect


As the first step of treatment, the healthcare provider should learn about your Diarrhea. Keep in mind that the quantity, frequency, and consistency of normal bowel movements are unique to every individual. Factors such as the food eaten, a person’s metabolisms and level of physical engagement, stress levels, medication one is taking, and the total amount of fluids taken influence the bowel movement. The healthcare practitioner will be interested in out-of-ordinary things and alterations associated with Diarrhea. To this end, they will ask a series of questions to determine the lab tests to run. The questions include:

  • Is there mucus or blood in the stool?
  • How frequently do you pass stool?
  • When did the Diarrhea start?
  • Do you have any other symptoms, including abdominal pain, fatigue, fever, nausea, or headache?
  • Have you taken antibiotics lately?
  • Have you been camping recently? Have you traveled out of the country? Where?
  • What is the color, consistency, and volume of the diarrhea stools?
  • Where and what have you eaten recently?
  • Are any of your close acquaintances, family members, or co-workers ill?

In cases where the patient’s Diarrhea is uncomplicated and clears after a few days, the doctor may not need to know what caused the gastrointestinal (G.I.) upset. However, in cases of severe, bloody, or long-lasting Diarrhea, the doctor may order several tests. The same case applies to patients who have traveled outside the U.S., and there is a possibility that some close them may be infected.

Laboratory Tests For Infectious Causes of Diarrhea

  • A Panel Tests For Detecting Gastrointestinal Pathogens         

Sample – Stool  

Description – This is a molecular test done to detect bacteria, viruses, and parasites; the panel of tests done determines the variety of pathogens identified.

Sample – Stool

Description – Stool samples are cultured in special nutrients media that allow pathogens to grow and thrive while inhibiting normal flora (bacteria found in the digestive tract) from growing. This test allows for the detection of several different bacteria. However, labs usually evaluate stool cultures with a focus on identifying common intentional pathogens such as:

  • Campylobacter species
  • Shigella species
  • Salmonella species

Sample – Stool  

Description – Done to detects the presence of toxin produced by C. difficile

Sample – Stool  

Description – #1. Toxin test – detects the Shiga toxin directly (used in conjunction with stool cultures)

#2. Pulsed-field Gel Electrophoresis (PFGE) is used in public health laboratories to detect and identify suspected E. coli subtypes in the event of an outbreak.

#3. Genetic tests – the rapid molecular tests (PCR) is used to identify Shiga toxin 1 gene (stx1) as well as Shiga toxin 2 gene (stx2)

  • Stool WBC            

Sample – Stool  

Description – This test is done to detects the presence of white blood cells in the stool owing to a bacterial infection, like Clostridium difficile

Antigen Test For Detecting Rotavirus         

Sample – Stool  

Description – A rapid antigen test done to detect the cause of Diarrhea common in children

  • Ova And Parasite Exam    

Sample – Stool  

Description – An evaluation of the stool using a microscope to detect parasites and their ova (eggs and or cysts).

  • Antigen Tests To Detect Specific Parasites:
  • Entamoeba histolytica
  • Giardia lamblia
  • Cryptosporidium parvum

Sample – Stool

Description – This is a test to detect the protein structure of the parasites. It is more sensitive than the O&P microscope exam, and a specific test is done to identify the parasites mentioned above

  • Antibody Tests For G.I. Parasites  

Sample – Blood 

Description – Some reference labs offer these tests. The tests are useful in detecting current infections but can also check for chronic or past diseases.

Examples of Tests for Non-infectious Causes of Diarrhea

  • Trypsin/Chymotrypsin      

Sample – Stool  

Description – Trypsin/chymotrypsin are two enzymes found in the stool when one’s pancreas is functioning well. The test helps determine whether the pancreas is functioning well. When there are low levels of the enzymes, it might indicate pancreatic disease or cystic fibrosis (C.F.).

  • Stool WBC            

Sample – Stool  

Description – An increased count of white blood cells in the stool might be indicative of inflammatory bowel disease (IBD).

  • Fecal Fat 

Sample – Stool  

Description – The test is done to measure the fat level/content in the stool. When there is an increased level of fat, it indicates malabsorption that can be caused by pancreatic insufficiency, celiac disease, or even cystic fibrosis.

Sample – Not applicable

Description – This test involves the oral food challenge, which helps diagnose food allergies. The tests are laborious, time-consuming, and require close supervision of the examiner owing to the potential of severe reactions such as life-threatening anaphylaxis. An alternative analysis is the food elimination test, which involves eliminating the suspected foods from the diet, and later on, reintroducing them one by one to determine which ones cause problems.

Sample – Sample – Blood             

Description – the Tissue transglutaminase antibody (tTG), IgA class primarily screens for celiac disease. The test is specific and exceptionally sensitive in testing for celiac disease. Other tests the medical practitioner may order include the total IgA and deamidated gliadin peptide antibodies (anti-DGP), IgG class of tTG, IgG, or IgA.

  • Lactose Tolerance Testing

Sample – Breath, blood 

Description – The test measures the amount of hydrogen in the patient’s breath or the chances in the glucose level in the patient’s blood after ingesting a standard amount of lactose to determine whether or not the patient can digest lactose properly.

  • Xylose Absorption Test      

Sample – Blood, urine    

Description – This test is done to determine how well the patient absorbs xylose. The patient ingests a standard amount of xylose, and then the levels of xylose are measure in the blood and urine. This helps determine whether they can absorb carbohydrates properly.

Sample – Stool  

Description – Detect inflammation resulting from IBD.

Sample – Blood 

Description – This test looks for anti-Saccharomyces cerevisiae antibodies (ASCA), an immune protein present in a patient with IBD.

Sample – Stool  

Description – These are tests done to detects any digestive tract bleeding emanating from colon cancer.

Sample – Blood 

Description – These are tests done to detect and diagnose carcinoid tumors, which, while rare, can cause chronic Diarrhea.

In some cases, a biopsy of the small intestines is ordered to detect parasitic infections, tumors, or celiac disease.

Other tests are performed to help determine the general health of an individual, which in turn helps unearth clues of diarrhea causes. Such tests include:

  • Complete Blood Count (CBC) – Helps detect anemia, which in turn detects an infection. For instance, in instances of elevated white blood cells eosinophil, it indicates a possibility of parasitic infection.
  • Osmolality – Urine, blood, or stool sample can be examined to evaluate electrolyte balance.