Digestive Health

Digestive Health

Causes of high serum amylaseinclude acute pancreatitis, pancreatic pseudocyst, pancreatic ascites, pancreatic abscess, neoplasm in or adjacent to pancreas, trauma to pancreas, and common duct stones.Nonpancreaticcauses of hyperamylasemia include inflammatory salivary lesions (eg, mumps), perforated peptic ulcer involving pancreas or not, intestinal obstruction and infarction, afferent loop syndrome, biliary tract disease including stones, aortic aneurysm, peritonitis, acute appendicitis, cerebral trauma, burns and traumatic shock, the postoperative state (with and without pancreatitis), diabetic ketoacidosis, and extrapancreatic carcinomas (especially of esophagus, lung, ovary). Amylase levels more than 25-fold the upper limit of normal are often found when metastatic tumors produce ectopic amylase. Such levels are higher than those usually found in cases of pancreatitis.3In renal insufficiency amylase is usually not more than three times the upper limit of normal. Moderate increases may be reported in normal pregnancy. Increases may be found with tubo-ovarian abscess, ruptured ectopic pregnancy, macroamylasemia, and with a substantial number of drugs, including morphine. Relationships between pancreatitis and hyperlipidemias types I, IV, and V are described. Amylasemia may be associated with hyperparathyroidism.Macroamylaseis a high molecular weight material, normal amylase complexed to high molecular weight protein such as immunoglobulin. It is characterized by high serum amylase and low to normal urine amylase. Macroamylase occurs in normal as well as abnormal subjects.4Other tests:Inpancreatitis, varying percentages of patients have the following other abnormalities in varying combinations: elevation of triglyceride, alkaline phosphatase, AST (SGOT), total bilirubin, white blood cell count, left shift. Calcium levels should be followed in fulminant pancreatitis, since extremely low serum calcium levels can evolve.Serum lipase and two-hour urine amylasemay both be extremely valuable. Although determination of serum methemalbumin has been advocated as a test for acute hemorrhagic pancreatitis, it is cumbersome and is not done in many American laboratories.Isoenzymesof amylase exist: pancreatic and salivary type, as noted under Limitations. They can be separated by polyacrylamide gel or agarose film electrophoresis, isoelectric focusing, ion exchange chromatography, and plant isoamylase inhibitors. A monoclonal antibody approach is described.3,5Amylase isoenzymes are separated in few laboratories. Where available the procedure is an expensive one. It is useful in assessing the decrease of pancreatic function in cystic fibrosis, in children older than five years, who may be candidates for enzyme replacement.

Digestive Health, General Health & Wellness

Serum lipase is usually normal in patients with elevated serum amylase, without pancreatitis, who have peptic ulcer, salivary adenitis, inflammatory bowel disease, intestinal obstruction, and macroamylasemia. Coexistence of increased serum amylase with normal lipase may be a helpful clue to the presence of macroamylasemia.1Lipase is elevated with amylase in acute pancreatitis, but the elevation of lipase is more prolonged.In work-up of pancreatitis, in addition to serum lipase and amylase, the 2-hour urine amylase is of value. Electrolytes, serum calcium, glucose, and acetone are also often needed. Immunoreactive trypsin is technically more difficult than lipase and probably no better.2The serum lipase:amylase ratio may help distinguish alcoholic from nonalcoholic pancreatitis. Ratios >2 (expressed as multiples of the upper limits of normal) suggest an alcoholic etiology.3Lipase isoform or isoenzymes have been studied.4

Digestive Health

Gastrin is secreted by antral G cells and stimulates gastric acid production, antral motility, and secretion of pepsin and intrinsic factor. The principle forms of gastrin in blood are G-34 (big gastrin, half-life is five minutes) and G-14 (minigastrin, half-life is five minutes). Each of these polypeptides circulates in nonsulfated (I) or sulfated (II) forms. Instilling acid into the stomach normally inhibits gastrin secretion. Elevated gastrin levels should be interpreted in light of gastric acid secretion and other parameters. The neuroendocrine tumors associated with the Zollinger-Ellison syndrome are characterized by elevated rates of gastric HCl secretion and upper gastrointestinal ulcer disease. Gastrin levels >500-600 pg/mL in a patient with basal acid hypersecretion often indicate gastrinoma, but antral G-cell hyperplasia cases can have gastrin levels >500 pg/mL and hyperchlorhydria. If gastrinoma is likely but fasting gastrin level is not diagnostic, the secretin test is the provocative test of choice. Absolute increase in serum gastrin level above the basal figure is preferred to percent change.4I.V. secretin normally diminishes gastrin, but serum gastrin increases in gastrinoma patients. Wolfe provides an explanation for this paradoxical effect.4Calcium infusion also stimulates gastrin release but does not distinguish other causes of ulcer as well as the secretin test. Protocols for stimulation tests are published.7Fifteen percent to 26% of Z-E patients have evidence of Werner syndrome (multiple endocrine neoplasia type 1). It may include hyperparathyroidism, islet cell tumors of the pancreas, pituitary tumors, Cushing syndrome (adrenal glands), and hyperparathyroidism.8Gastrinoma are malignant in 62% of cases, and 44% of patients have metastases.No consistent relationship has been established betweenHelicobacter pylori(Campylobacter pylori) and gastric acid secretion or serum gastrin levels.Features of gastrinoma additional to those of peptic ulcer may include diarrhea and steatorrhea.Gastrinomas are usually found in the pancreas but they may be primary in the duodenum. A few cases in which a gastrinoma was primary in the stomach have been reported. The morphology is that of foregut carcinoids.9

Liver & Kidney Health, Digestive Health

Alanine Aminotransferase (ALT) measurements are particularly useful in the diagnosis and management of certain liver diseases, e.g., viral hepatitis and cirrhosis. ALT activity in tissue is generally much lower than aspartate aminotransferase (AST) activity and is found in highest concentrations in the liver. Significant elevations of ALT occur only in diseases of the liver. ALT is often measured in conjunction with AST to determine whether the source of the AST is the liver or the heart. ALT is normally not elevated in cases of myocardial infarction, i.e., a normal ALT, in conjunction with an elevated AST, tends to suggest cardiac disease. However, slight elevations of ALT may occur if an infarct destroys a very large volume of heart muscle.

Digestive Health

Conditions associated with marked fecal leukocytes, blood and mucus include diffuse antibiotic associated colitis, ulcerative colitis, shigellosis, salmonellosis,Campylobacter, andYersiniainfection.Salmonella typhimay evoke a monocyte response. Conditions associated with modest numbers of fecal leukocytes include early shigellosis involving small bowel, antibiotic associated colitis, and amebiasis. Conditions associated with an absence of fecal leukocytes include toxigenic bacterial infection, giardiasis, and viral infections. In a review the methylene blue stain for polymorpholeukocytes had a high sensitivity 85% and specificity 88% for bacterial diarrhea (Shigella,Salmonella,Campylobacter). Positive predictive value was 59%. Negative predicative value was 97%. Combined with a history of abrupt onset, greater than four stools per day and no vomiting before the onset of diarrhea the stool methylene blue stain for fecal polymorphonuclear leukocytes was a very effective presumptive diagnostic test for bacterial diarrhea.1A positive occult blood test may also be suggestive of acute bacterial diarrhea. Neither method is sufficiently sensitive or specific to preëmpt the use of culture.2Similar findings including a sensitivity of 81% and specificity 74% were observed when both tests were positive.3

Digestive Health, General Health & Wellness

The major sources of amylase are the pancreas and the salivary glands. The most common cause of elevation of serum amylase is inflammation of the pancreas (pancreatitis). In acute pancreatitis, serum amylase begins to rise within 6-24 hours, remains elevated for a few days and returns to normal in 3-7 days. Other causes of elevated serum amylase are inflammation of salivary glands (mumps), biliary tract disease and bowel obstruction. Elevated serum amylase can also be seen with drugs (e.g., morphine) which constrict the pancreatic duct sphincter preventing excretion of amylase into the intestine.

Liver & Kidney Health, Digestive Health

This panel may be helpful in assessing liver injury, diagnosing liver diseases, and monitoring treatment of liver diseases and adverse effects of hepatotoxic drugs [1]. This panel includes total protein, albumin, globulin (calculated), albumin/globulin ratio, total bilirubin, direct bilirubin, indirect bilirubin (calculated), alkaline phosphatase (ALP), aspartate aminotransferase (AST), and alanine aminotransferase (ALT).⁠⁠⁠⁠⁠⁠⁠ALT, AST, ALP, and bilirubin are common liver chemistry analytes that can be used to evaluate liver injury. ALT is a more liver-specific marker than AST. The latter also is present in the peripheral circulation during episodes of skeletal, cardiac, and smooth muscle injury. Elevated ALT and AST levels disproportionate to ALP levels indicate hepatocellular injury; elevated ALP and bilirubin levels disproportionate to ALT and AST levels indicate cholestatic injury. In the absence of identifiable risk factors, ALT or AST levels above the upper limit of the normal range are associated with increased liver-related mortality [1]. Evaluation of direct and indirect bilirubin levels is helpful for assessing the possibility of hepatocellular disease [1]. Elevated direct bilirubin levels imply hepatocellular dysfunction or cholestasis.Albumin is a marker of liver synthetic function; low levels may indicate liver disease of more than 3 weeks' duration [1]. Total protein levels reflect the sum of albumin and globulins and may aid in the diagnosis of disorders involving the liver, kidney, or bone marrow.This panel may be useful in evaluating individuals who are taking hepatotoxic drugs as well as those with viral hepatitis, symptoms or signs of chronic liver disease, conditions associated with a high risk of developing liver disease, lifestyle risk factors for nonalcoholic fatty liver disease, or a family history of liver disease [2].Because many liver diseases cause characteristic abnormalities in selected liver chemistry analytes, results of individual analytes in this panel may aid in differential diagnosis. An abnormal test result may need to be confirmed by repeat testing and/or performing a clarifying test. For example, measurement of gamma-glutamyl transferase activity (not included in this panel) can help determine whether an elevated ALP result reflects hepatic disease [1].Note that liver enzymes are markers of liver injury, not direct measurements of hepatic function. Bilirubin, albumin, and prothrombin time are markers of liver synthetic function [1,2].The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.References1. Kwo PY, et al.Am J Gastroenterol. 2017;112(1):18-35.2. Newsome PN, et al.Gut. 2018;67(1):6-19.

Liver & Kidney Health, Digestive Health

Elevated GGT is found in all forms of liver disease. Measurement of GGT is used in the diagnosis and treatment of alcoholic cirrhosis, as well as primary and secondary liver tumors. It is more sensitive than alkaline phosphatase, the transaminases, and leucine aminopeptidase in detecting obstructive jaundice, cholangitis, and cholecystitis. Normal levels of GGT are seen in skeletal diseases; thus, GGT in serum can be used to ascertain whether a disease, suggested by elevated alkaline phosphatase, is skeletal or hepatobiliary.

Infectious Diseases, Digestive Health

C difficilecan produce two toxins, designated A and B, that have pathogenic effects in humans. Antibiotic-associated pseudomembranous colitis has been shown to result from the action of these two toxins. This disease has been associated with clindamycin use but it is now recognized that pseudomembranous colitis can follow administration of virtually any antibiotic. More than 70% of the cases in a large series were associated with cephalosporin therapy.1The clinical spectrum of antibiotic-induced syndromes caused byC difficileincludes patients with symptoms of acute abdomen with little or no diarrhea, as well as cases with fulminant life-threatening diarrhea. Nosocomial transmission and reinfection with different strains occurs as do spontaneous cases without prior antimicrobial therapy. In cases where cessation of antibiotic therapy does not produce a response, specific therapy with oral vancomycin, metronidazole, or oral bacitracin may be effective. Detection of the toxins produced byC difficile(rather than culture of the organism) is important in the determining therapy of this potentially fatal disease. The routine use of culture does not seem appropriate because of the costs and the high rate of recovery of strains which do not produce toxin.

Digestive Health, General Health & Wellness

Confirmatory evidence for diagnosis of pancreatitis.

Cancer Screening, Digestive Health

This assay intended for the in vitro quantitative determination of CA 19-9 tumor-associated antigen in human serum and plasma.1The assay is indicated for the serial measurement of CA 19-9 to aid in the management of patients diagnosed with cancers of the exocrine pancreas. The test is useful as an aid in the monitoring of disease status in those patients having confirmed pancreatic cancer who have levels of CA 19-9 at some point in their disease process exceeding the median concentration determined for the apparently healthy cohort.The CA 19-9 values measured are defined by the use of the monoclonal antibody 1116-NS-19-9. The 1116-NS-19-9-reactive determinants on a glycolipid having a molecular weight of approximately 10,000 daltons are measured. This mucin corresponds to a hapten of Lewis-a blood group determinants and is a component of a number of mucous membrane cells.3,4Mucin occurs in fetal gastric, intestinal, and pancreatic epithelia. Low concentrations can also be found in adult tissue in the liver, lungs, and pancreas.2,5CA 19-9 assay values can assist in the differential diagnosis and monitoring of patients with pancreatic carcinoma (sensitivity 70% to 87%).6-12There is no correlation between tumor mass and the CA 19-9 assay values; however, patients with CA 19-9 serum levels >10,000 units/mL almost always have distal metastasis.2

Digestive Health

Amebas and certain other parasites cannot be seen in stools containing barium. Amebic cysts,Giardiacysts, and helminth eggs are often recovered from formed stools. Mushy or liquid stools (either normally passed or obtained by purgation) often yield trophozoites. Purgation does not enhance the yield ofGiardia. Formalin will preserve protozoan cysts and larvae and the eggs of helminths. It is used for concentration procedures. PVA will preserve the trophozoite stage of protozoa. A trichrome-stained smear may be prepared from PVA-fixed material. PVA cannot be concentrated; therefore, they should always be accompanied by a portion of the specimen in formalin.Parasites commonly identified in the stool of AIDS patients includeCryptosporidium,Isospora,Entamoeba histolytica,andGiardia lamblia.The pathogenic nature ofBlastocystis hominis,which is commonly observed in stool of healthy and symptomatic patients, is controversial. A review of the literature by Miller and Minshew indicated that there was no convincing proof of a causal relationship betweenB hominisand symptoms, that there was no correlation between resolution of symptoms with therapy or with the disappearance of the organism from stool, and that treatment directed at the indication ofB hominisis not indicated.4Doyle et al have observed a role forBlastocystisin acute and chronic gastroenteritis but are unable to conclude whether the role is one of association or causation.5In a large children's hospital study of nosocomial diarrhea rotavirus,C difficileand enteric adenovirus were recovered. Stool for ova and parasites and bacterial stool cultures yielded no pathogens.6Optimal diagnostic yield is obtained by the examination of fresh, warm stool by an experienced technologist. Formalin will preserve protozoan cysts and larvae and the eggs of helminths. It is used for concentration procedures. PVA will preserve the trophozoite stage of protozoa. A trichrome-stained smear may be prepared from PVA-fixed material. Specimens submitted in PVA cannot be concentrated; therefore, they should always be accompanied by a portion of the specimen in formalin. Formed stools may be preserved in formalin or refrigerated in a secure container until they can be added to the formalin and PVA container for transport to the laboratory.

Infectious Diseases, Digestive Health

The diagnosis ofSchistosoma haematobiuminfection is achieved by examination of urine specimens for eggs. Both 24-hour and spot urine samples should be examined to enhance detection.S haematobiumegg excretion exhibits a circadium rhythm, with the peak occurring between noon and 3 PM. Egg output is enhanced by physical exercise combined with fluid intake prior to urination. In very light or chronic infections, eggs may be very difficult to detect in urine; consequently, multiple urine sample examinations may be required. Occasionally eggs ofS mansonimay also be detected in urine.

Digestive Health, Nutrition & Vitamins

Offered as part of multiple lab tests

Infectious Diseases, Digestive Health

Offered as part of multiple lab tests

Allergy Testing, Digestive Health

This test is an allergen-specific IgE antibody test that quantifies an individual’s IgE response to gluten. It is an in vitro quantitative assay, which is intended to be used in conjunction with other clinical information to aid in the diagnosis of food allergy [1].While allergen-specific serum IgE testing is considered comparable to skin testing in many instances, both the American Academy of Allergy, Asthma, and Immunology and the American College of Allergy, Asthma, and Immunology recognize that allergen-specific serum IgE testing may be preferred in some clinical situations. These include 1) the presence of widespread skin disease, 2) the recent use of antihistamines or other medications that can affect the results of allergy skin tests, 3) uncooperative patients, and 4) medical history suggesting that allergen skin testing would pose a significant risk for a serious allergic reaction [1].Food-specific IgE tests are extremely sensitive. However, a positive test result only indicates that a patient is IgE sensitized to the food of concern. Many IgE-sensitized patients do not develop any symptoms when this food is ingested. A diagnosis of food allergy should only be made by a trained medical provider, after conducting a thorough clinical evaluation [2,3]. While food-specific IgE test results may contribute to that evaluation, they cannot replace it. In this regard, detection of food-specific IgE in serum provides evidence of IgE sensitization, but a history of clinical reactivity to the food of concern, is required to make a diagnosis of IgE-mediated food allergy. Moreover, several forms of food hypersensitivity are not associated with the presence of food-specific IgE in serum.More specific information about this allergen can be found athttp://www.phadia.com/en/products/allergy-testing-products/immunocap-allergen-information/food-of-plant-origin/grains/gluten-/References1. Bernstein IL, et al.Ann Allergy Asthma Immunol.2008;100(suppl 3):S1-S148.2. Sampson HA, et al.J Allergy Clin Immunol. 2014;134:1016-1025.3. Boyce JA, et al.J Allergy Clin Immunol. 2010;126(6 suppl):S1-S58.

Digestive Health

AST is widely distributed throughout the tissues with significant amounts being in the heart and liver. Lesser amounts are found in skeletal muscles, kidneys, pancreas, spleen, lungs, and brain. Injury to these tissues results in the release of the AST enzyme to general circulation. In myocardial infarction, serum AST may begin to rise within 6-8 hours after onset, peak within two days and return to normal by the fourth or fifth day post infarction. An increase in serum AST is also found with hepatitis, liver necrosis, cirrhosis, and liver metastasis.

Digestive Health

Offered as part of multiple lab tests

Cancer Screening, Digestive Health

Increased serum CEA levels have been detected in persons with primary colorectal cancer and in patients with other malignancies involving the gastrointestinal tract, breast, lung, ovarian, prostatic, liver and pancreatic cancers. Elevated serum CEA levels have also been detected in patients with nonmalignant disease, especially patients who are older or who are smokers. CEA levels are not useful in screening the general population for undetected cancers. However, CEA levels provide important information about patient prognosis, recurrence of tumors after surgical removal, and effectiveness of therapy.

Digestive Health

Ammonia is one of the by-products of protein metabolism. Elevated blood ammonia levels have been associated with severe liver dysfunction such as hepatic encephalopathy, coma resulting from cirrhosis, severe hepatitis, Reye's syndrome and drug hepatotoxicity. Also, elevated blood ammonia has been reported in cardiac failure, azotemia, and pulmonary emphysema. Correlation between plasma ammonia and the degree of encephalopathy can be erratic.

Digestive Health

Offered as part of multiple lab tests

Cancer Screening, Digestive Health

A large percentage of patients with gastrointestinal tumors (such as pancreatic, liver, gastric, colorectal tumors) and some other malignancies have been shown to have elevated serum CA 19-9 levels. Serum CA 19-9 levels may be useful for monitoring disease activity or predicting relapse following treatment. CA 19-9 should not be used as a screening test.

Cancer Screening, Digestive Health

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.

Digestive Health

The presence of leukocytes is an indicator of inflammation. Generally, inflammation is a product of bacteria-host interaction.

Digestive Health, Infectious Diseases

Diseases caused by human parasites remain on a worldwide basis among the principle causes of morbidity and mortality. Correct diagnosis of intestinal parasitic infection depends on proper collection, transport, detection and identification of parasites in stool specimens. Symptoms range from malaise to death. Treatment is dependent upon examining multiple stool specimens due to the erratic shed rates of some parasites.

Digestive Health, Infectious Diseases

Giardiasis is recognized as an important human intestinal disease in most areas of the world. The causative organism, Giardia duodenalis (lamblia) is the most frequently identified protozoan parasite in stool specimens submitted to public health laboratories. This parasite has been implicated in a number of epidemics and the endemicity in the U.S., is well recognized. Acute symptoms of Giardiasis may include diarrhea, malabsorption, abdominal cramps, anorexia, nausea, weight loss, flatulence, anemia, and general weakness lasting from several weeks to several months. Chronic infections can also occur with or without an acute phase, are often associated with treatment failure and may result in recurrent symptoms. Infection with Giardia may also be asymptomatic.

Digestive Health

Tissue Transglutaminase Antibody, IgA, is useful in diagnosing gluten-sensitive enteropathies, such as Celiac Sprue Disease, and an associated skin condition, dermatitis herpetiformis. The IgG test is useful in patients who are IgA-deficient. The IgG test also provides support for gluten-sensitive enteropathies beyond the IgA test.

Digestive Health, Hormone Testing

For the diagnosis and monitoring of gastrin-secreting tumors, gastric ulcer, Zollinger-Ellison syndrome. Increased in pernicious anemia.

Digestive Health, Liver & Kidney Health

The concentration of bile acids in serum is elevated in patients with many structural liver diseases, due to the inability of the liver to extract bile acids efficiently from portal blood. Metabolic liver diseases such as Gilbert disease, Crigler-Najjar syndrome, or Dubin-Johnson syndrome do not appear to cause elevated bile acid concentrations. Bile acid levels may be altered even when other liver function tests are normal and may serve as a sensitive and specific indicator of liver disease.Intrahepatic cholestasis of pregnancy (ICP) is a temporary condition caused by maternal liver dysfunction during pregnancy. It is characterized by intense generalized pruritus (itchiness) which usually begins in the third trimester. ICP is also known as cholestatic jaundice of pregnancy, cholestatic hepatosis, icterus gravidarum, and obstetric cholestasis.There are several laboratory tests which can be done to confirm a diagnosis of cholestasis of pregnancy, including bile acids. Maternal blood levels of bile salts are often at least three times the normal level in ICP; however, the levels may be 10 to 100 times normal. Blood tests can also reveal increased levels of other liver enzymes that indicate general liver dysfunction, such as ALT, AST, and alkaline phosphatase. While ALT/AST levels may be normal or slightly elevated, alkaline phosphatase levels are almost always higher than normal (though this may be due, in part, to the alkaline phosphatase added to the mother's blood from the placenta). However, if the liver enzymes are extremely elevated, other causes, such as viral hepatitis, should be considered. In the absence of bile acid tests, elevated ALT, AST and/or alkaline phosphatase levels in the setting of intense pruritus are generally adequate to diagnose cholestasis of pregnancy.Though it may cause extreme discomfort, cholestasis of pregnancy is regarded as benign to the mother; however, it has been widely established that ICP poses a significant increased risk to the fetus and is associated with an increased incidence of stillbirth. Fetal death in ICP is a real risk and the primary objective of treatment is to make certain that the baby is born before stillbirth occurs. While the fetal death rate for untreated patients is around 10%, studies in which patients are induced before term have found fetal mortality rate to be 0% to 2%. The danger from ICP is eliminated when the child is safely delivered and labor is induced when the fetus' lungs are mature, regardless of any other test results.After delivery, the symptoms in the mother usually decrease within 48 hours of delivery and disappear completely within four weeks postpartum. Cholestasis of pregnancy does not cause permanent liver impairment to the mother and the liver returns to normal function, once the baby is delivered.

Digestive Health

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Digestive Health

Offered as part of multiple lab tests

Digestive Health

In enteric fever caused bySalmonella typhi,S choleraesuis, orS enteritidis, blood culture may be positive before stool cultures, and blood cultures are indicated early; urine cultures may also be helpful.Diarrhea is common in patients with the acquired immunodeficiency syndrome (AIDS). It is frequently caused by the classic bacterial pathogens as well as unusual opportunistic bacterial pathogens and parasitic infestation. (Giardia,Cryptosporidium, andEntamoeba histolyticafrequently reported.)Cryptosporidium,Isospora, andPneumocystiscan occur with AIDS. Rectal swabs are useful for the diagnosis ofNeisseria gonorrhoeaeandChlamydiainfections. AIDS patients are also subject to cytomegalovirus,Salmonella,Campylobacter,Shigella,C difficile, herpes, andTreponema pallidumgastrointestinal tract involvement.Diarrhea Syndromes Classified by Predominant FeaturesSyndrome(Anatomic Site)FeaturesCharacteristic EtiologiesGastroenteritis (stomach)VomitingRotavirusNorwalk virusStaphylococcal food poisoningBacillus cereusfood poisoningEnteritis(small bowel)Watery diarrheaLarge-volume stools, few in numberEnterotoxigenicEscherichia coliVibrio choleraeAny enteric microbeInflammatory bowel diseaseDysentery, colitis (colon)Small-volume stools containing blood and/or mucus and many leukocytesShigellaCampylobacterSalmonellaInvasiveE coliPlesiomonas shigelloidesAeromonas hydrophilaVibrio parahaemolyticusClostridium difficileEntamoeba histolyticaInflammatory bowel diseaseIn acute or subacute diarrhea, three common syndromes are recognized: gastroenteritis, enteritis, and colitis (dysenteric syndrome). With colitis, patients have fecal urgency and tenesmus. Stools are frequently small in volume and contain blood, mucus, and leukocytes. External hemorrhoids are common and painful. Diarrhea of small bowel origin is indicated by the passage of few large volume stools. This is due to accumulation of fluid in the large bowel before passage. Leukocytes indicate colonic inflammation rather than a specific pathogen. Bacterial diarrhea may be present in the absence of fecal leukocytes and fecal leukocytes may be present in the absence of bacterial or parasitic agents (ie, idiopathic inflammatory bowel disease).2See table. Although most bacterial diarrhea is transient (1 to 30 days) cases of persistent symptoms (10 months) have been reported. The etiologic agent in the reported case wasShigella flexneridiagnosed by culture of rectal swab.3In infants younger than one year of age, a history of blood in the stool, more than 10 stools in 24 hours, and temperature greater than 39°C have a high probability of having bacterial diarrhea.4,5Diarrhea is also a common side effect of long-term antibiotic treatment. Although often associated withClostridium difficile, other bacteria and yeasts have been implicated.6

Digestive Health

Proper therapy depends on identification of the specific variety of malaria parasite. Release of trophozoites and RBC debris results in a febrile response. Periodicity of fever correlates with type of malaria (see table). Organisms are most likely to be detected just before onset of fever, which is predictable in many cases. Sampling immediately upon onset of fever is the most desirable time to obtain blood. Alternatively, in cases negative by these means but with a strong clinical history, multiple sampling at different times in the fever cycle may prove successful.Changes in Infected RBCs Useful to Identify Malaria SpeciesPlasmodiumSpeciesInfected RBC EnlargedPresence of Schüffner DotsPresence of Maurer DotsMultiple Parasites per RBCParasite With Double Chromatin DotsParasite With Sausage- Shaped GametocytesP vivax++—RareRare—P falciparum——++++P ovale±+————P malariae——+———

Autoimmune & Inflammation, Digestive Health

Gastric Parietal Cell Antibodies are found in 90% of patients with pernicious anemia. They are also found in autoimmune chronic atrophic gastritis preceding pernicious anemia. The antigenic target is the H+/K+ ATPase gastric proton pump responsible for parietal cell acid generation in the stomach.

Digestive Health, Autoimmune & Inflammation

Calprotectin is a non-specific marker of bowel inflammation. Subsequent to white blood cell migration into the intestine, this neutrophil protein may be detected in the stool. Thus, fecal calprotectin levels may assist in diagnosis of inflammatory bowel disease; Crohn's disease and ulcerative colitis and other disorders characterized by bowel inflammation. It can also be used as an aid in the differentiation of IBD from irritable bowel syndrome.

Digestive Health, Autoimmune & Inflammation

Offered as part of multiple lab tests

Digestive Health

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Digestive Health

The present standard of care includes testing for and treatment ofHelicobacter pyloriin patients with documented ulcer disease or recurrent dyspepsia. Although serologic assays have been widely used for the diagnosis ofH pylori, the increasing availability of direct tests in the form of stool antigen and urea breath test provide diagnostic alternatives with higher positive predictive values. Use of “direct” tests leads to a reduction in unnecessary treatment, which is important because of the continuing concern regarding antimicrobial treatment and the emergence of antibiotic resistance. These tests each have the added feature of being able to be used as a test of cure when administered a month or more after completion of eradication therapy.

Digestive Health

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

Digestive Health, Infectious Diseases

The importance ofHelicobacter pyloriin gastrointestinal diseases has increased greatly since Marshall and Warren described the presence of Campylobacter-like organisms in the antral mucosa of patients with histological evidence of antrum gastritis and peptic ulcers, especially duodenal ulcers. The strong correlation between the presence ofH. pyloriwithin histologically confirmed gastritis, peptic ulcer disease and gastric carcinoma and lymphoma, as well as disease resolution afterH. pylorieradication, indicates a causative relationship. The ecological niche in humans appears to be restricted to the stomach and duodenum. Patients who harbor the organism are divided into two basic groups. The first are those who are said to be "colonized". These patients have the organism, yet have no signs of gastrointestinal disease. Those with gastrointestinal symptoms and a positiveH. pyloriantigen test are considered to be infected.

Digestive Health, Autoimmune & Inflammation

Gluten is a protein found in wheat, rye and barley. Gliadin is the alcohol-soluble fraction of gluten that contains the bulk of the toxic components of gluten. It is resistant to degradation in the human upper gastrointestinal tract and is able to pass through the epithelial barrier of the intestine. Gluten sensitivity is a state of heightened immunological responsiveness to ingested gluten. It represents the spectrum of diseases with diverse manifestations such as enteropathy (celiac disease), dermatopathy (dermatitis herpetiformis), neurological disorders (ataxia and neuropathy), and may be underlying reason for many other nonspecific symptoms like anemia, chronic fatigue, joint inflammation and pain, migraines, depression, attention-deficit disorder, epilepsy, osteoporosis and osteopenia, infertility, recurrent fetal loss, vitamin deficiencies, short stature, failure to thrive, delayed puberty, dental enamel defects, and autoimmune disorders. Patients with gluten sensitivity are reported to have increased mortality and its prevalence in the general population is up to 12%.Antibodies to deamidated gliadin peptide and tissue transglutaminase are specific to celiac disease while antibodies to native gliadin are present in patients with and without gastrointestinal manifestations and are serological evidence of gluten sensitivity. Another subset of patients may have gluten sensitivity expressed in the form of allergic reaction to foods containing gluten like wheat. All of those patient groups may benefit from gluten-free diet.This screening profile is designed to aid in the diagnosis of different forms of gluten sensitivity.Step One:The screening starts with testing for tTG IgA and DGP IgG.1,2When any or both of the results are positive, testing stops and the interpretive comment on the report would read: "Suggestive of celiac disease or other gluten-sensitive enteropathies. Subsequent testing forEndomysial Antibody, IgA [164996]and/or genetic testing forCeliac Disease HLA DQ Association [167082]may be indicated for further patient evaluation." When result is negative, testing will reflex to the second step.Step Two:In the second step, the test for IgG antibodies to native gliadin (AGA) is performed. AGA currently remain the most sensitive markers of the whole spectrum of gluten sensitivity including all the extraintestinal manifestations.1,3When the result is positive, testing stops and the interpretive comment would read: "Suggestive of nonceliac gluten sensitivity. The patient may benefit from a gluten-free diet." When the result is negative, testing will reflex to the third step.Step Three:In the third and last step, the test for wheat allergen-specific IgE is performed. Allergic reaction to wheat may mimic the clinical presentation of gluten sensitivity like celiac disease and is one of the common food allergies in children. The triggering agent, however, may not be just gluten but any other protein or combination of proteins found in wheat.4Because wheat allergy patients may also be allergic to other grains with similar proteins like rye and barley,4they will benefit from the gluten-free diet. When the result is positive, testing stops and the interpretive comment would read: "Suggestive of wheat allergy. The patient may benefit from a gluten-free diet." When the result is negative, testing stops and the interpretive comment would read: “Not suggestive of gluten sensitivity.”

Digestive Health

Celiac disease is characterized by the presence of Transglutaminase, Gliadin, and Reticulin Antibodies. Such patients display a hypersensitivity to gluten (wheat) in their diet. The antibody is undetectable when patients with hypersensitivity are placed on gluten-free diets. Antibody IgA is more specific and IgG is more sensitive to Celiac disease.

Digestive Health

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.

Digestive Health

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.

Digestive Health

Toxoplasmosis is a parasitic infection caused by the protozoanToxoplasma gondii. Approximately 23% of the immunocompetent population are asymptomatic carriers of the parasite. The combination of high titers of IgG and IgM antibodies toToxoplasma gondiiis consistent with infection in the last three months. High titers of IgG and low to medium titers of IgM antibodies toToxoplasma gondiiare consistent with infection in the last three to six months.

Digestive Health

Antibodies tosaccharomyces cerevisiaeare found in approximately 75% of patients with Crohn's disease, 15% of patients with ulcerative colitis, and 5% of the healthy population. High titers of antibody increase the likelihood of disease, and specifically Crohn's disease, and are associated with more aggressive disease.

Infectious Diseases, Digestive Health

Offered as part of multiple lab tests

Infectious Diseases, Digestive Health

During the last several years, increased rates ofC difficileinfection have been reported, noting more severe disease and an associated increase in mortality.C difficileinfection remains a disease mostly associated with health care (at least 80%), with the elderly remaining at greatest risk. More disease has been reported in traditionally "low-risk" individuals, such as healthy persons in the community and peripartum women. Severe disease outbreaks ofC difficileinfection in health care facilities have been attributed to the emergence of a hypervirulent epidemic strain, known by its names—assigned by various typing schemes—as restriction enzyme analysis type BI, North American Pulsed Field type 1 (NAP1), or PCR ribotype 027. BI/NAP1/027 has spread widely, and it appears more virulent due to its increased production of toxins A and B and its production of an additional toxin known as binary toxin. This strain is also believed to produce more spores, leading to enhanced persistence in the environment.

Digestive Health, Autoimmune & Inflammation

Fecal lactoferrin is sensitive and specific for detecting inflammation in chronic IBD. This noninvasive test may be useful in screening for inflammation in patients presenting with abdominal pain and diarrhea.

Digestive Health, Infectious Diseases

Helicobacter pyloriis a gram-negative microaerophilic curved bacillus with an affinity for human gastric mucosa.H. pylorihas been identified as an important pathogen in the upper GI tract. The casual relationship betweenH. pyloriand chronic active gastritis, duodenal ulcers, and gastric ulcers has been well documented. PyloPlus® UBT breath tests provide a non-invasive and non-hazardous method for detecting currentH. pyloriinfection using urea breath analysis.

Digestive Health, Autoimmune & Inflammation

Inflammatory bowel disease is a chronic disorder of the lower gastrointestinal tract that may occur in three forms: Crohn's disease (CD), ulcerative colitis (UC), and indeterminate colitis (IC). Its prevalence in the adult population approaches 0.3%.1The differential diagnosis of the different forms of IBD is often difficult, time-consuming, and invasive.2The gold standard for diagnosis is endoscopy with biopsies for histologic examination.3In recent years, however, a number of serological markers have been introduced. The most commonly employed serological markers of IBD are anti-Saccharomyces cerevisiaeantibody (ASCA) and atypical perinuclear antineutrophil cytoplasmic antibody (pANCA). ASCA positivity is found predominantly in patients with CD, while pANCA positivity is found predominantly in patients with UC.2A combination of ASCA and pANCA has a specificity of as high as 99% for differentiation of CD from UC.3Nevertheless, there are a substantial number of patients with IBD who are negative for both. The addition of novel serological markers improves the sensitivity of the conventional ASCA/pANCA combination.3About two-thirds of patients with CD develop either a stricturing or penetrating disease course within 10 years after diagnosis. As many as 80% of all CD patients undergo surgery at least once during the course of their disease. Consequently, the identification of individuals susceptible to the development of more complicated disease behavior would allow for earlier and more aggressive treatment.4This profile offers three novel markers: antichitobioside IgA (ACCA), antilaminaribioside IgG (ALCA), antimannobioside IgG (AMCA), together with anti-Saccharomyces cerevisiaeIgG (gASCA) and pANCA. These markers provide additional diagnostic and prognostic information depending on the combination of results.3-6The antibodies included in the panel are ASCA (anti-Saccharomyces cerevisiaeantibodies), ALCA (antilaminaribioside carbohydrate antibodies), ACCA (antichitobioside carbohydrate antibodies), and AMCA (antimannobioside carbohydrate antibodies).3,5,6Numerous studies of CD have demonstrated an association between ileal disease and the presence of ACCA,3ALCA,3,6AMCA,6and ASCA.3,5-10Among these antibodies, the association with localization to the small intestine increased with the number of positive antibodies and with the concentration of individual antibodies.3,5,6,9,11A more aggressive or complicated disease course in CD (as indicated by stricturing or perforation of the intestine or need for surgery), has also been associated with the presence of ACCA,3,5ALCA,3,5,6AMCA,3,5and ASCA.3,5,6,8-10Among these antibodies, the association with complicated disease behavior or surgery increased with the number and concentration of antibodies.3,5,9,11

Digestive Health

The polyclonal antibodies used in this assay are specifically directed against defined sequences of the human pancreatic elastase molecule. The enzyme stability is remarkably high despite its proteolytic activity, as elastase is found in feces in about a sixfold concentration as in pancreatic fluid. The determination of enzyme concentration in feces reflects the exocrine secretory capacity of the pancreas.

Digestive Health, Autoimmune & Inflammation

Celiac disease is a gluten enteropathy occurring in both children and adults. The disease is probably underdiagnosed in that it may affect as much as 1% of the population in the United States. The condition is characterized by a sensitivity to gluten (found in wheat, barley, and rye) that causes inflammation and atrophy of the villi of the small intestine, malabsorption, etc. This sensitivity to gluten may also be seen in dermatitis herpetiformis. Strict avoidance of gluten in the diet will control disease activity, and antibodies to serum markers will disappear with time.

Digestive Health, Autoimmune & Inflammation

Disorders of the lower gastrointestinal tract in adults and children are among the most common conditions and may pose a difficult diagnostic problem. They account for 1 in 20 of all general practitioner consultations and their symptoms are frequently ill-defined.1Those disorders include a wide range of pathologic conditions, including irritable bowel syndrome (IBS), inflammatory bowel disease (IBD) that includes Crohn's disease (CD), ulcerative colitis (UC), and indeterminate colitis; microscopic colitis, infectious colitis, small intestinal bacterial overgrowth, celiac disease, and colon neoplasia (including colon cancer).2The most prevalent condition is IBS. Its prevalence in Europe and North America is estimated to be 10% to 15%.3Prevalence of celiac disease increased at least four times during the last 50 years and approaches 0.9%.4The incidence rate of Crohn’s disease increased from 0.1 (three decades ago) to 4.6 (in 2003) per 100,000 children and the incidence of UC from 0.5 to 3.2 per 100,000 children.5The prevalence of IBD in the adult population is approaching 0.3%.6Recently another condition termed “gluten sensitivity” emerged as an important and often underdiagnosed and undertreated disease.7-11It is reported that as many as 12% of the healthy population may have serological evidence of gluten sensitivity.9Difficulties in differential diagnosis of those conditions often prompt clinicians to use an exclusion approach by performing tests to rule out the alternative etiologies.2Interestingly, one study shows that most of the celiac disease serological test requests are now from general practitioners rather than gastroenterologists.12Another study reports that 72% of general practitioners endorsed IBS as a diagnosis of exclusion.2Endoscopy with biopsies for histological examination remains the gold standard for the diagnosis of many of these conditions.13In recent years, however, introduction of a number of new and improved serological tests may allow for reduction in the number of intestinal biopsies.14The cascade includes three testing steps:Step 1: Celiac Disease Screen:The cascade begins with a celiac screen that includes testing for tTG IgA and DGP IgG.10When any or both of the results are positive, the testing stops and the interpretive comment on the report would read: “Suggestive of celiac disease or other gluten-sensitive enteropathies. Subsequent testing forEndomysial Antibody, IgA [164996]and/or genetic testing forCeliac Disease HLA DQ Association [167082]may be indicated for further patient evaluation.” When the result is negative, the testing reflexes to the second step.Step 2: Inflammatory Bowel Disease Screen:Inflammatory bowel disease screen includes testing for IgG antibodies to anti-Saccharomyces cerevisiae(ASCA) and atypical perinuclear antineutrophil cytoplasmic antibodies (pANCA). This profile of tests aids in the serological identification of patients with IBD and in differentiation among its three clinical forms: CD, UC, and indeterminate colitis. When the marker for CD (ASCA IgG) is positive, the clinical sensitivity for CD is reported to be as high as 74.4% and specificity for IBD as high as 94.4%.15When atypical pANCA (a marker of UC) is positive, the clinical sensitivity for UC is reported to be as high as 70% and specificity as high as 80%.16It must be emphasized that neither of the markers negatively rules out IBD. Similarly, the presence of these antibodies does not strictly confirm the diagnosis of IBD.17Testing for Step 2 is described below and (depending on the combination of results) the interpretive comment on the report would be one of the following: When ASCA IgG is positive and atypical pANCA is negative, testing stops and the comment would read: “Suggestive of Crohn's disease. Subsequent testing with theCrohn's Disease Prognostic Profile [162020]that includes antiglycan antibodies AMCA, ALCA, ACCA, and gASCA may aid in the differentiation of clinical forms of CD and prognosis of disease progression.” When ASCA IgG is negative or equivocal and atypical pANCA is positive testing stops and the comment would read: “Suggestive of ulcerative colitis.” When both ASCA IgG and atypical pANCA are positive testing stops and the comment would read: “Suggestive of IBD. Subsequent testing with theCrohn's Disease Prognostic Profile [162020]that includes antiglycan antibodies AMCA, ALCA, ACCA, and gASCA may aid in the differentiation of clinical forms of IBD and prognosis of disease progression.” When all results are negative, then the testing reflexes to the third step.Step 3: Nonceliac Gluten Sensitivity Screen:The nonceliac gluten sensitivity screen includes testing for IgG antibodies to gliadin with reported clinical sensitivity as high as 87% (for untreated clinically defined celiac disease patients) and specificity as high as 91%.18Recent reports show that there is a significant subset of patients who have normal histology for celiac disease, negative for antibodies to DGP and tTG, positive for antigliadin antibodies and clinically indistinguishable from those with celiac disease. Those patients constitute the so-called “nonceliac gluten sensitivity” group, and many of them will benefit from a gluten-free diet. This group of patients is also reported to have increased mortality.7-10,14When the result is positive, the testing stops and the interpretive comment on the report would read: “Suggestive of nonceliac gluten sensitivity. The patient may benefit from a gluten-free diet.” When all results are negative, the testing stops and the interpretive comment on the report would read: “Suggestive of irritable bowel syndrome (IBS). Careful evaluation of the patient's history, physical examination, and application of Rome III diagnostic criteria may help to rule in or rule out the diagnosis of IBS. Subsequent testing forCalprotectin, Fecal [123255]may be recommended. If IBD is strongly suspected, subsequent testing with theCrohn's Disease Prognostic Profile [162020]that includes antiglycan antibodies AMCA, ALCA, ACCA, and gASCA may aid in differential diagnosis.”

Liver & Kidney Health, Digestive Health

Offered as part of multiple lab tests