Diarrhea

Indications for Testing

Symptoms
- Persistent or chronic diarrhea
- Bloody diarrhea
- Diarrhea in association with systemic illness
Patient history
- Immunocompromised status
- Returned traveler
- Hospitalized patient
Outbreak identification

Laboratory Testing

Acute diarrhea (≤14 days)

Acute Diarrhea (≤14 Days)
For most cases, no testing is necessary at initial presentation – most etiologies of acute diarrhea are viral and do not require treatment Exceptions (Steffen, 2015) Immunocompromised or hospitalized patients Returned travelers with any of the following Fever >101.3F degrees Bloody stools Dysentery
Virus	Testing Options
Norovirus	Polymerase chain reaction (PCR) – most sensitive/specific test; available as a standalone test or in a viral panel Enzyme immunoasssay (EIA) (antigen detection) – not as sensitive as PCR Electron microscopy – insensitive and lab specific
Rotavirus	PCR – viral panel EIA – more sensitive than scanning electron microscopy (SEM) Immunochromatographic assay (ICA) – performs better than latex agglutination Latex agglutination – not recommended
Adenovirus 40/41	PCR – viral panel EIA – good sensitivity/specificity compared to electron microscopy
Sapovirus, astrovirus	PCR – viral panel
Bacterial Testing
Indications	Testing Options
May be appropriate for certain groups (eg, returned travelers)	Stool culture Sensitivity highly variable; excellent specificity Sensitivity depends on specimen collection and transport Generally identifies Campylobacter, Salmonella, Shigella Should include E. coli for Shiga-like toxin by EIA (antigen) Sensitivity lower than PCR Turnaround time – 24-96+ hrs Gastrointestinal bacterial panel by PCR – detects the following Campylobacter jejuni/coli Campylobacter upsaliensis Salmonella spp Shiga-like toxin 1 from E. coli Shiga-like toxin 2 from E. coli Shigella spp/enteroinvasive E. coli (EIEC) Campylobacter antigen by immunochromatography – may be used in place of culture Only specific for C. jejuni/C. coli For Yersinia and Vibrio spp – stool culture does not readily recover these spp; laboratory must include a specific culture condition or selective media for identification Clostridium difficile testing – refer to ARUP Consult topic
Parasitic Testing
Indications	Testing Options
May be indicated initially in the following Returned travelers with appropriate travel history Immunocompromised patients Community outbreaks	Do not use ova and parasite exams for most patients in acute setting Variable sensitivity Not cost effective Requires 3+ specimens Does not readily detect Cystoisospora, Cryptosporidium, Cyclospora, or microsporidia Cannot differentiate E. histolytica from E. dispar If parasitic testing deemed necessary – refer to testing options in persistent or chronic diarrhea table below

Persistent diarrhea (>14 days) or chronic diarrhea (>30 days)

Persistent (>14 Days) or Chronic Diarrhea (>30 Days)
Parasites often cause prolonged diarrhea; if no previous testing has been performed, consider also testing for Salmonella sp, Shigella sp, and Campylobacter spp (Steffen, 2015) Parasitic testing leads to highest yields at this stage
Comprehensive Testing
Organisms	Testing Options
Giardia lamblia/intestinalis/duodenalis Cryptosporidium hominis, C. parvum Entamoeba histolytica Cyclospora cayetanensis Dientamoeba fragilis	Gastrointestinal parasite polymerase chain reaction (PCR) panel Available with or without microsporidia PCR Very sensitive and specific for listed organisms
Individual Specific Organism Testing
Organism	Testing Options
Giardia duodenalis (synonyms Giardia lamblia, Giardia intestinalis)	Giardia antigen by enzyme immunoassay (EIA) – preferred if not using PCR panel If first specimen is negative and suspicion still exists, consider repeating for Giardia
Cryptosporidium hominis, C. parvum	Cryptosporidium spp antigen (EIA or direct fluorescent antibodies [DFA]) – preferred if not using PCR panel Microscopic detection in stool Requires special stains (eg, modified acid fast and multiple stool specimens) Less sensitive than stool EIA
Entamoeba histolytica	Intestinal disease Entamoeba antigen (EIA) preferred if not using PCR panel
Cystoisospora belli, Cyclospora cayetanensis	Microscopic examination of stool using special stain (eg, modified acid fast) if not using PCR
Dientamoeba fragilis	Ova and parasite exam – preferred if not using PCR panel Very difficult to identify in stains; insensitive
Microsporidia	Microscopic examination of stool using microsporidial stain (eg, modified acid fast) if not using PCR Stool examination May require testing of multiple specimens

Differential Diagnosis

Gastrointestinal disorders
- Post-diarrheal malabsorption
- Inflammatory bowel disease
- Irritable bowel syndrome
- Celiac disease
- Pancreatic insufficiency
- Diverticulitis
Immunodeficiency syndromes
Cystic fibrosis
Lactose intolerance
Malignancy
- Primary or metastatic cancer
  - Colorectal cancer
  - VIPoma syndrome
Laxative abuse

Diarrhea in Healthy Pediatric Patients Testing Algorithm

Read more about Diarrhea in Healthy Pediatric Patients Testing Algorithm

Diarrhea in Hospitalized Adult Patients Testing Algorithm

Read more about Diarrhea in Hospitalized Adult Patients Testing Algorithm

Diarrhea in Immunocompromised Hosts Testing Algorithm

Read more about Diarrhea in Immunocompromised Hosts Testing Algorithm

Diarrhea in Primary Care Adults Testing Algorithm

Read more about Diarrhea in Primary Care Adults Testing Algorithm

Diarrhea in Returned Traveller or Immigrant Testing Algorithm

Read more about Diarrhea in Returned Traveller or Immigrant Testing Algorithm

Diarrhea may be infectious or noninfectious and presents with acute (<14 days) or persistent (>14 days) symptoms. Community-acquired disease is most common. Viruses (norovirus predominates) are the most common cause of acute infectious diarrhea in community dwellers. Bacterial diarrhea represents only 1-5% of diarrhea cases and is often associated with clustering of cases or outbreaks. Clostridium difficile cases, while often nosocomially acquired, are increasing in community dwellers. Parasites are an infrequent or rare cause of acute diarrhea and tend to be sporadic in nature except in at-risk populations (eg, returned travelers, immunocompromised individuals).

Epidemiology

Incidence – the CDC estimates >350 million acute diarrheal incidences annually (Mead, 1999)
- The CDC's Foodborne Diseases Active Surveillance Network (FoodNet) reports ~48 million cases of foodborne illness annually

Risk Factors

Immunocompromised status
- HIV, primary immunodeficiency
  - Most common organisms include viruses, C. difficile, Campylobacter jejuni, Salmonella spp, E. coli, Giardia, Cryptosporidium spp, and microsporidia
- Transplantation (solid organ and stem cell)
  - Usually noninfectious
  - Infectious diarrhea most commonly caused by viruses (norovirus predominates), C. difficile, and microsporidia
Advanced age (>65 years)
- Salmonella spp and Shigella spp may require treatment, so identification is important
Comorbid illnesses (eg, chronic heart, liver, or kidney disease; diabetes mellitus)
- Increased risk of complications (eg, sepsis)
Institutional residency
- Norovirus
Daycare setting
- Norovirus
- Giardia
- Cryptosporidium spp
- Salmonella spp

Clinical Presentation

Community acquired
- Acute diarrhea (acute gastroenteritis)
  - Duration – 1-14 days
  - Transmission – foodborne, waterborne, or outbreak associated
  - Most commonly caused by viruses and occasionally bacteria
- Persistent diarrhea
  - Duration – >14 days, often longer
  - Often noninfectious
  - Testing for parasites may be considered
  - Persistent diarrhea may lead to malabsorption following an infectious diarrhea
Hospital acquired
- Presentation may be similar to community-acquired disease
- Most commonly caused by viruses
- Rule out bacterial agent C. difficile if patient history is correct

Organisms Associated with Diarrhea (CDC, 2014)

Norovirus

Epidemiology
- Incidence
  - Leading cause of nonbacterial gastroenteritis worldwide
  - Norovirus causes millions of infections annually, with outbreaks commonly occurring in all age groups and in varied environments
    - Cruise ships
    - Restaurants (salad bar contamination most common)
    - Schools
    - Daycares
    - Healthcare facilities
- Transmission
  - Fecal-oral route by ingestion of contaminated food (eg, shellfish) or water
  - Can be airborne (in vomitus)
  - Low infectious dose; can survive relatively high levels of disinfectants and varying temperatures
Clinical presentation
- Usually mild or self-limiting disease with high transmission rates
- Onset of symptoms occurs 24-48 hours after infection
- Symptoms – generally last 12-60 hours
  - Acute onset diarrhea
  - Vomiting with abdominal cramps
  - Nausea
  - Fever
  - Headache
- Transplant patients often have chronic diarrhea
  - Symptoms in small bowel transplant patients resemble allograft rejection

Rotavirus

Epidemiology
- Incidence
  - Most important cause of severe dehydrating diarrhea worldwide in children <5 years
    - Declined 67% in U.S. since introduction of vaccine
    - Universal infection – nearly all children have circulating antibodies by 2-3 years
- Transmission
  - Fecal-oral route
Clinical presentation
- Varies from asymptomatic to severe dehydration leading to death
- Mild fever and emesis for 2-3 days
- Watery diarrhea for 3-5 days following fever
  - Bloody diarrhea rare
- Severe and prolonged disease may occur in patients with the following
  - Significant malnutrition
  - Immune deficiencies (eg, HIV)
  - Other chronic disease such as diabetes mellitus, congenital heart disease, or pulmonary disease
- May involve extra intestinal sites – central nervous system, liver, spleen, or kidney, especially in immunocompromised children

Campylobacter

Epidemiology
- Incidence
  - Leading cause of bacterial gastroenteritis worldwide
  - Peak incidence in children <5 years
- Occurrence
  - Sporadic, but most cases occur in spring and fall
- Transmission
  - Associated with incorrect food handling practices, consumption of poorly cooked poultry or raw milk, contact with pets, travel
  - Outbreaks most often associated with raw milk and contaminated water
Clinical presentation
- Varies from asymptomatic infection to severe inflammatory diarrhea
- Onset of symptoms occurs 2-5 days after ingestion of contaminated food or water
- Symptoms – generally last 7-10 days
  - Abdominal pain
  - Watery stools containing blood and mucous
  - Fever
  - Nausea or vomiting
- Complications
  - Reactive arthritis (increased risk if individual is positive for HLA-B27 phenotype)
  - Guillain-Barré syndrome
  - Hemolytic uremic syndrome (HUS)
  - Complications in patients with HIV or hypogammaglobulinemia – relapse osteomyelitis (especially with HLA-B27 phenotype)
  - Local complications – hemorrhage, megacolon
  - Bacteremic complications – cellulitis, meningitis

Salmonella

Epidemiology
- Incidence
  - Most U.S. cases are related to international travel or immigrant status
  - Remaining cases are from large, sporadic outbreaks
    - Incidence nearly equal to Campylobacter
- Transmission
  - Undercooked or uncooked foods (eg, raw meat and vegetables, poultry, eggs, milk, salad dressing, shrimp, peanut butter)
  - Contact with infected animals
  - Contact with nonsymptomatic patients
Clinical presentation
- Typhoid fever
  - Incubation period is 3-21 days
  - Prodrome of chills, headache, sore throat, fever, anorexia, cough
  - Progresses to rash (rose spots), epistaxis, diarrhea, relative bradycardia
  - Blood cultures are of higher yield than stool cultures for typhoid fever
    - 90% have positive blood cultures in week 1; drops to 50% by week 3
  - Complications
    - Late complications found in untreated adults – intestinal perforation, gastrointestinal hemorrhage
    - Rare complications – pancreatitis, hepatic and splenic abscesses, endocarditis, pericarditis, orchitis, meningitis, parotitis, osteomyelitis
    - Up to 5% of infected patients develop chronic carrier state
      - Usually occurs in patients with gall bladder disease or gastric carcinomas
- Enteritis
  - Onset of symptoms occur 6-48 hours after exposure
  - Symptoms – gererally last 1-2 days
    - Fever, headache
    - Intestinal symptoms – diarrhea (watery), abdominal pain

Shiga-toxigenic E. coli

Epidemiology
- Incidence
  - Under-recognized illness
  - Not uncommon
- Transmission
  - Person-to-person contact in daycare facilities and nursing homes
  - Consumption of undercooked meats and produce (washing produce has been shown to be ineffective)
Clinical presentation
- Watery diarrhea progressing to bloody diarrhea
- Abdominal pain
- Symptoms usually resolve within 8 days
- Hemolytic uremia syndrome (HUS) – fever, renal dysfunction and hemolytic anemia, thrombocytopenia
  - Virulence is attributable to production of Shiga-like toxin 1 and/or 2
  - Most frequent in children <15 years and adults >65 years

Shigella spp

Epidemiology
- Incidence
  - Common in countries with poor sanitation
  - Accounts for small percentage of reported outbreaks of foodborne illness in U.S.
- Transmission
  - Fecal-oral route; no nonhuman hosts
  - Higher-risk groups – daycare personnel and clients, nursing home residents, and men who have sex with men
Clinical presentation
- Onset of symptoms occurs 12-50 hours after exposure
- Symptoms
  - Diarrhea
    - Frequently bloody
    - May contain mucous or pus
  - Fever
  - Abdominal pain, cramps
  - Dysentery (10-30 stools/day)
- Associated with Reiter syndrome (arthritis, uveitis, urethritis)
- Complications
  - Reactive arthritis (increased risk of development if patient is positive for HLA-B27 allele)
  - Hemolytic uremic syndrome (HUS) (usually S. dysenteriae type 1)

Yersinia spp

Epidemiology
- Incidence
  - Most often in young children
  - Y. pseudotuberculosis and Y. pestis are uncommon causes of gastrointestinal disease
- Transmission
  - Soil, water, animals, food
  - Y. enterocolitica found in meats (eg, beef, pork), oysters, fish, and unpasteurized milk
Clinical presentation
- Onset of symptoms occurs 24-48 hours after ingestion of contaminated food or drink
- Symptoms
  - Diarrhea (loose, watery, or bloody stools)
  - Abdominal pain
  - Fever
  - Infections with Y. enterocolitica and Y. pseudotuberculosis can be asymptomatic, mild, or severe, with infection resolving within a few weeks (with or without use of antibiotics)
  - Yersinia infections are known for mimicking appendicitis
- Complications include reactive arthritis which can manifest 1-4 weeks post infection (increased risk of development if patient is positive for HLA-B27 allele)
  - The most commonly affected joints are knees and ankles, but other joints such as toes, fingers, and wrists can be involved
  - In most cases, 2-4 joints become involved sequentially and asymmetrically over a period of a few days to 2 weeks
    - Joint fluid is sterile
  - Chronic joint disease or ankylosing spondylitis occurs rarely
  - Acute arthritis persists for 1-4 months
  - Reiter syndrome (arthritis, uveitis, and urethritis) may occur
  - Less common nonsuppurative sequelae of Y. enterocolitica infections include reactive uveitis, iritis, conjunctivitis, glomerulonephritis, urethritis, hemolytic uremic syndrome (HUS)

Vibrio spp

Epidemiology
- Incidence
  - Vibrio cholerae
    - Several pandemics have occurred
    - No major outbreaks in U.S. since 1911
  - V. vulnificus
    - Outbreak reported in New Orleans after hurricane Katrina
    - Usually several lethal cases annually in Florida, typically in summer months
- Transmission
  - Ingestion of contaminated seafood (eg, crab, shrimp, lobster)
    - V. parahaemolyticus is the leading cause of bacterial diarrhea associated with seafood
  - Through open wounds in sea water
Clinical presentation
- Onset of symptoms occurs within 16 hours of ingestion of contaminated seafood for healthy individuals
- Symptoms
  - Watery diarrhea
  - Abdominal pain
  - Cramps
  - Vomiting
- Immunocompromised individuals and patients with cirrhosis may present with primary septicemia
  - Associated with >50% mortality
- No associated long-term complications

Giardia duodenalis (synonyms Giardia lamblia, Giardia intestinalis)

Epidemiology
- Incidence
  - Most common cause of parasite-associated diarrhea in the U.S.
  - Increased frequency in children, men who have sex with men, and residents of institutional care facilities
- Transmission
  - Waterborne, foodborne, or fecal-oral
Clinical presentation
- Most infections are asymptomatic
- Symptoms may last from weeks to months
  - Acute or chronic nonbloody diarrhea, nausea, vomiting, dehydration, abdominal discomfort, malabsorptive symptoms (eg, flatulence, greasy malodorous stools)
- Intermittent or recurrent symptoms are common

Cryptosporidium spp

Epidemiology
- Incidence
  - Increased risk in patients with HIV, residents of households with infected patients, daycare personnel and clients, and returned travelers
- Transmission
  - Waterborne, sporadic, or outbreak associated
    - Found in large outbreaks associated with contaminated water sources
    - Can occur year round when artificial water storage systems are involved
Clinical presentation
- Immunocompetent patients
  - Usually asymptomatic or mild, self-limiting gastroenteritis
  - Nonbloody, watery diarrhea, dehydration, nausea, vomiting, abdominal pain, low-grade fever, and malaise lasting from a few days to >30 days
- Immunocompromised patients
  - General immunodeficiencies (particularly T-cell deficiencies) – chronic diarrhea (often more severe than expected for pathogen), dehydration, weight loss
  - HIV – chronic diarrhea; others include cholecystitis, hepatitis, pancreatitis

Entamoeba histolytica

Epidemiology
- Incidence
  - Increased risk in men who have sex with men, recent immigrants, residents of institutional care facilities, returned travelers, and HIV patients
  - Typically limited to individual cases with possible spread to sex partners or close contacts
- Transmission
  - Waterborne, foodborne, or fecal-oral
Clinical presentation
- Most individuals are asymptomatically colonized (~90%)
  - Subacute onset
- Disease may be intestinal or extraintestinal
  - Intestinal disease
    - Fulminant or chronic, with abdominal pain, tenderness, tenesmus, and bloody diarrhea
  - Extraintestinal disease
    - May include liver, brain, and lung abscesses

Cystoisospora belli

Epidemiology
- Incidence
  - Increased risk in HIV patients, recent immigrants, and travelers from endemic regions
- Transmission
  - Waterborne
Clinical presentation
- Immunocompetent patients
  - Acute, self-limiting watery or malodorous diarrhea (similar to Giardia or Cryptosporidium infection)
- Immunocompromised patients
  - General immunodeficiencies – chronic diarrhea (occasionally severe), dehydration, weight loss
  - HIV – diarrhea, cholecystitis, reactive arthritis

Microsporidia

Epidemiology
- Incidence
  - Undetermined in non-HIV populations
  - Increased risk in HIV patients presenting with chronic diarrhea
    - Predominately affects immunocompromised hosts
    - Includes Enterocytozoon bieneusi, Encephalitozoon intestinalis, Pleistophora, Septata, Vittaforma spp
    - ~15% prior to combination antiretroviral therapy (cART)
    - Rates are lower for patients on cART
- Transmission
  - Waterborne
Clinical presentation
- Immunocompetent patients
  - Rare cause of acute, self-limiting diarrhea
- Immunocompromised patients (most often with HIV)
  - Chronic diarrhea, dehydration, anorexia, weight loss, abdominal pain, nausea, vomiting

Cyclospora cayetanensis

Epidemiology
- Incidence
  - Unknown in U.S.; usually tropical/subtropical regions
- Transmission
  - Foodborne or waterborne
  - Clustered outbreaks associated with contaminated food products
  - Recent outbreaks occurring at higher frequency
    - Not associated with foreign travel, but rather, foreign food products sold domestically
- Clinical presentation
  - Immunocompetent patients
    - Anorexia, nausea, emesis, flatulence, watery diarrhea, low grade fever, fatigue, cramping
    - Typically does not resolve without treatment
  - Immunocompromised patients
    - May cause chronic diarrhea
  - Endemic – frequent mild or asymptomatic cases

Tests generally appear in the order most useful for common clinical situations. Click on number for test-specific information in the ARUP Laboratory Test Directory.

Gastrointestinal Viral Panel by PCR 2013577
Method: Qualitative Polymerase Chain Reaction

Recommended Use

Aid in the diagnosis of GI infections caused by viral pathogens, including adenovirus (serotypes 40 and 41), astrovirus, norovirus (genogroups 1 and 2), rotavirus, and sapovirus

Use as a sensitive alternative to traditional antigen testing

Norovirus Group 1 and 2 by PCR 0051281
Method: Qualitative Reverse Transcription Polymerase Chain Reaction

Recommended Use

Detect norovirus groups 1 and 2

Limitations

Negative result does not rule out the presence of PCR inhibitors in the patient specimen or test-specific nucleic acid concentrations below the level of detection by this test

Rotavirus Antigen by EIA 0065088
Method: Qualitative Enzyme Immunoassay

Recommended Use

Diagnose rotavirus-associated gastroenteritis

For antigen testing panel that includes adenovirus and rotavirus, refer to rotavirus and adenovirus 40-41 antigens

Rotavirus and Adenovirus 40-41 Antigens 0065067
Method: Qualitative Enzyme Immunoassay

Recommended Use

Diagnose rotavirus- and adenovirus-associated gastroenteritis

Adenovirus 40-41 Antigens by EIA 0065066
Method: Qualitative Enzyme Immunoassay

Recommended Use

Diagnose adenovirus-associated gastroenteritis

Refer to rotavirus and adenovirus 40-41 antigens for combination testing

Stool Culture and E. coli Shiga-like Toxin by EIA 0060134
Method: Culture/Identification

Recommended Use

Preferred test for suspected bacterial diarrhea evaluation

Cultures include Salmonella, Shigella, Campylobacter, and E. coli 0157, and EIA for Shiga-like toxin from E. coli

Limitations

If an isolate requires testing for Shiga-like toxin (eg, STEC), refer to E. coli Shiga-like toxin by EIA

Gastrointestinal Bacterial Panel by PCR 2012678
Method: Qualitative Polymerase Chain Reaction

Recommended Use

Use as a sensitive alternative to traditional stool culture to detect the most common gastrointestinal bacterial pathogens: Salmonella, Shigella/Enteroinvasive E. coli, Campylobacter jejuni/coli, and shiga-toxigenic E. coli

This test can also detect Campylobacter upsaliensis, which cannot be readily cultured

Limitations

A negative result does not rule out the presence of PCR inhibitors in the patient specimen or test-specific nucleic acid in concentrations below the level of detection by this test

Gastrointestinal Parasite and Microsporidia by PCR 2011660
Method: Qualitative Polymerase Chain Reaction

Recommended Use

Do not order for patients with diarrhea developed during prolonged hospitalization

Most comprehensive and sensitive alternative to traditional, insensitive ova and parasite examinations of stool specimens for the evaluation of gastrointestinal infections

Detect Cryptosporidium hominis, C. parvum, Cyclospora cayetanensis, Dientamoeba fragilis, Entamoeba histolytica, Giardia lamblia/intestinalis/duodenalis, and microsporidia by PCR

Clostridium difficile toxin B gene (tcdB) by PCR 2002838
Method: Qualitative Polymerase Chain Reaction

Recommended Use

Recommended rapid, stand-alone diagnostic test for C. difficile-associated diarrhea

Gastrointestinal Parasite Panel by PCR 2011150
Method: Qualitative Polymerase Chain Reaction

Recommended Use

Do not order for patients with diarrhea developed during prolonged hospitalization

Use as a sensitive alternative to traditional, insensitive ova and parasite examinations of stool specimens

Detect Cryptosporidium hominis, C. parvum, Cyclospora cayetanensis, Dientamoeba fragilis, Entamoeba histolytica, and Giardia lamblia/intestinalis/duodenalis

Giardia Antigen by EIA 0060048
Method: Qualitative Enzyme Immunoassay

Recommended Use

Test for persistent diarrhea (>14 days) or known risk factors if Giardia duodenalis (synonyms Giardia lamblia, Giardia intestinalis) is the suspected infectious agent

Cryptosporidium Antigen by EIA 0060045
Method: Qualitative Enzyme Immunoassay

Recommended Use

Test for persistent diarrhea (>14 days) or known risk factors if Cryptosporidium spp is the suspected infectious agent

Parasitology Stain by Modified Acid-Fast 0060046
Method: Qualitative Concentration/Stain

Recommended Use

Test for persistent diarrhea (>14 days) or known risk factors if Cryptosporidium, Cyclospora, or Cystoisospora is the suspected infectious agent

Microsporidia by PCR 2011626
Method: Qualitative Polymerase Chain Reaction

Recommended Use

Preferred test to diagnose microsporidia in immunocompromised patients with persistent diarrhea if Encephalitozoon spp (E. instestinalis/E. hellem/E. cuniculi) or Enterocytozoon bieneusi is the suspected infectious agent

Limitations

The nucleic acid from E. intestinalis, E. hellem, and E. cuniculi will be detected by this test but cannot be differentiated

A negative result does not rule out the presence of PCR inhibitors in the patient specimen or test-specific nucleic acid in concentrations below the level of detection by this test

Microsporidia Stain by Modified Trichrome 0060050
Method: Qualitative Stain

Recommended Use

Can be used for follow-up of negative PCR result when suspicion of microsporidia infection remains high

Entamoeba histolytica Antigen, EIA 0058001
Method: Qualitative Enzyme Immunoassay

Recommended Use

Test for persistent diarrhea (>14 days) or known risk factors if E. histolytica is the suspected infectious agent

Ova and Parasite Exam, Fecal (Immunocompromised or Travel History) 2002272
Method: Qualitative Concentration/Trichrome Stain/Microscopy

Recommended Use

If parasite infection is suspected as cause of persistent diarrhea (>14 days), specific pathogen testing is recommended

Do not order for patients who develop diarrhea during a prolonged hospitalization

Limitations

Due to the various shedding cycles of many parasites, 3 separate stool specimens collected over a 10-day period are recommended for ova and parasite examination

A single negative result does not rule out the possibility of a parasitic infection

Stool antigen testing is the optimal test method for determining the parasitic presence of Giardia, Cryptosporidium spp, or Entamoeba histolytica

Does not specifically detect Cryptosporidium, Cyclospora, Cystoisospora, or microsporidia

Follow-up

For Cryptosporidium, refer to the Cryptosporidium antigen by EIA test; for Cyclospora and Cystoisospora, refer to parasitology stain by modified acid-fast; for microsporidia, refer to microsporidia stain

Guidelines

Farthing M, Salam MA, Lindberg G, Dite P, Khalif I, Salazar-Lindo E, Ramakrishna BS, Goh K, Thomson A, Khan AG, Krabshuis J, LeMair A, WGO. Acute diarrhea in adults and children: a global perspective. J Clin Gastroenterol. 2013; 47(1): 12-20. PubMed

Foodborne Diseases Active Surveillance Network (FoodNet). Centers for Disease Control and Prevention. Atlanta, GA [Last updated Nov 2016; Accessed: Dec 2016]

Guerrant RL, Van Gilder T, Steiner TS, Thielman NM, Slutsker L, Tauxe RV, Hennessy T, Griffin PM, DuPont H, Sack RB, Tarr P, Neill M, Nachamkin I, Reller LB, Osterholm MT, Bennish ML, Pickering LK, Infectious Diseases Society of America. Practice guidelines for the management of infectious diarrhea. Clin Infect Dis. 2001; 32(3): 331-51. PubMed

Manatsathit S, DuPont HL, Farthing M, Kositchaiwat C, Leelakusolvong S, Ramakrishna BS, Sabra A, Speelman P, Surangsrirat S, Working Party of the Program Committ of the Bangkok World Congress of Gastroenterology 2002. Guideline for the management of acute diarrhea in adults. J Gastroenterol Hepatol. 2002; 17 Suppl: S54-71. PubMed

Manual for the Surveillance of Vaccine-Preventable Diseases . Centers for Disease Control and Prevention. Atlanta, GA [Last updated Apr 2016; Accessed: Jun 2017]

Riddle MS, DuPont HL, Connor BA. ACG Clinical Guideline: Diagnosis, Treatment, and Prevention of Acute Diarrheal Infections in Adults. Am J Gastroenterol. 2016; 111(5): 602-22. PubMed

General References

Barr W, Smith A. Acute diarrhea. Am Fam Physician. 2014; 89(3): 180-9. PubMed

Bernstein DI. Rotavirus overview. Pediatr Infect Dis J. 2009; 28(3 Suppl): S50-3. PubMed

Calderaro A, Gorrini C, Montecchini S, Peruzzi S, Piccolo G, Rossi S, Gargiulo F, Manca N, Dettori G, Chezzi C. Evaluation of a real-time polymerase chain reaction assay for the laboratory diagnosis of giardiasis. Diagn Microbiol Infect Dis. 2010; 66(3): 261-7. PubMed

DuPont HL. Clinical practice. Bacterial diarrhea. N Engl J Med. 2009; 361(16): 1560-9. PubMed

Glass RI, Parashar UD, Estes MK. Norovirus gastroenteritis. N Engl J Med. 2009; 361(18): 1776-85. PubMed

Graves NS. Acute gastroenteritis. Prim Care. 2013; 40(3): 727-41. PubMed

Grimwood K, Forbes DA. Acute and persistent diarrhea. Pediatr Clin North Am. 2009; 56(6): 1343-61. PubMed

Hill DR, Ryan ET. Management of travellers' diarrhoea. BMJ. 2008; 337: a1746. PubMed

Hunt JM. Shiga toxin-producing Escherichia coli (STEC). Clin Lab Med. 2010; 30(1): 21-45. PubMed

Khan MA, Bass DM. Viral infections: new and emerging. Curr Opin Gastroenterol. 2010; 26(1): 26-30. PubMed

Mathis A, Weber R, Deplazes P. Zoonotic potential of the microsporidia. Clin Microbiol Rev. 2005; 18(3): 423-45. PubMed

Mead PS, Slutsker L, Dietz V, McCaig LF, Bresee JS, Shapiro C, Griffin PM, Tauxe RV. Food-related illness and death in the United States. Emerg Infect Dis. 1999; 5(5): 607-25. PubMed

Patel MM, Hall AJ, Vinjé J, Parashar UD. Noroviruses: a comprehensive review. J Clin Virol. 2009; 44(1): 1-8. PubMed

Pawlowski SW, Warren CA, Guerrant R. Diagnosis and treatment of acute or persistent diarrhea. Gastroenterology. 2009; 136(6): 1874-86. PubMed

Pierce KK, Kirkpatrick BD. Update on human infections caused by intestinal protozoa. Curr Opin Gastroenterol. 2009; 25(1): 12-7. PubMed

Recommendations for Diagnosis of Shiga Toxin–Producing Escherichia coli Infections by Clinical Laboratories. October 16, 2009, Vol. 58, No. RR-12. Centers for Disease Control and Prevention. Atlanta, GA [Published Oct 2009; Accessed: Jan 2017]

Steffen R, Hill DR, DuPont HL. Traveler's diarrhea: a clinical review. JAMA. 2015; 313(1): 71-80. PubMed

References from the ARUP Institute for Clinical and Experimental Pathology

Beal SG, Couturier MR, Gander RM, Doern CD. Diagnostic Algorithm for the Diagnosis of Pediatric Parasitic Gastroenteritis. J Clin Lab Anal. 2016; 30(2): 155-60. PubMed

Couturier BA, Hale DC, Couturier MR. Association of Campylobacter upsaliensis with persistent bloody diarrhea. J Clin Microbiol. 2012; 50(11): 3792-4. PubMed

Couturier BA, Jensen R, Arias N, Heffron M, Gubler E, Case K, Gowans J, Couturier MR. Clinical and Analytical Evaluation of a Single-Vial Stool Collection Device with Formalin-Free Fixative for Improved Processing and Comprehensive Detection of Gastrointestinal Parasites J Clin Microbiol. 2015; 53(8): 2539-48. PubMed

Hymas W, Atkinson A, Stevenson J, Hillyard D. Use of modified oligonucleotides to compensate for sequence polymorphisms in the real-time detection of norovirus. J Virol Methods. 2007; 142(1-2): 10-4. PubMed

Khot PD, Fisher MA. Novel approach for differentiating Shigella species and Escherichia coli by matrix-assisted laser desorption ionization-time of flight mass spectrometry. J Clin Microbiol. 2013; 51(11): 3711-6. PubMed

Rawlins ML, Gerstner C, Hill HR, Litwin CM. Evaluation of a western blot method for the detection of Yersinia antibodies: evidence of serological cross-reactivity between Yersinia outer membrane proteins and Borrelia burgdorferi. Clin Diagn Lab Immunol. 2005; 12(11): 1269-74. PubMed

Rossi A, Couturier MR. The Brief Case: Cryptosporidiosis in a Severely Immunocompromised HIV Patient. J Clin Microbiol. 2016; 54(9): 2219-21. PubMed

Shakespeare WA, Davie D, Tonnerre C, Rubin MA, Strong M, Petti CA. Nalidixic acid-resistant Salmonella enterica serotype Typhi presenting as a primary psoas abscess: case report and review of the literature. J Clin Microbiol. 2005; 43(2): 996-8. PubMed

Medical Reviewers

Couturier, Marc Roger, PhD, D(ABMM), Medical Director, Microbial Immunology, Parasitology and Fecal Testing, and Infectious Disease Rapid Testing at ARUP Laboratories; Assistant Professor of Clinical Pathology, University of Utah

Fisher, Mark A., PhD, D(ABMM), Medical Director, Bacteriology and Antimicrobials at ARUP Laboratories; Assistant Professor of Clinical Pathology, University of Utah

Hillyard, David R., MD, Medical Director, Molecular Infectious Diseases at ARUP Laboratories; Professor of Clinical Pathology, Adjunct Professor of Biology, University of Utah

Schlaberg, Robert, MD, MPH, Medical Director, Microbial Amplified Detection, Virology, and Fecal Chemistry; and Assistant Medical Director, Virology and Molecular Infectious Disease at ARUP Laboratories; Assistant Professor of Clinical Pathology, University of Utah

Autoimmune Neuropathies - Neuropathic Disease

Celiac Disease

Celiac Disease Testing for Symptomatic Individuals Algorithm

Clostridium difficile

Clostridium difficile-Associated Disease (CDAD) Testing Algorithm

Human Immunodeficiency Virus - HIV

Inflammatory Bowel Disease - IBD

Malabsorption

Emerging and Zoonotic Infections - Marc Roger Couturier, PhD, D(ABMM) (FREE CME credit) (60 min)

Shigatoxigenic E. coli: A Fully Emerged, Still-Underappreciated Pathogen - Marc Roger Couturier, PhD, D(ABMM) (FREE CME credit) (48 min)

Content Reviewed:

April 2017

Last Update: April 2017


	Diarrhea. ARUP Consult^©. Retrieved June 27, 2017, from: https://arupconsult.com/content/diarrhea

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Diarrhea

Indications for Testing

Laboratory Testing

Differential Diagnosis

Diarrhea in Healthy Pediatric Patients Testing Algorithm

Diarrhea in Hospitalized Adult Patients Testing Algorithm

Diarrhea in Immunocompromised Hosts Testing Algorithm

Diarrhea in Primary Care Adults Testing Algorithm

Diarrhea in Returned Traveller or Immigrant Testing Algorithm

Epidemiology

Risk Factors

Clinical Presentation

Organisms Associated with Diarrhea (CDC, 2014)

Guidelines

General References

References from the ARUP Institute for Clinical and Experimental Pathology

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