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Test ID GIP Gastrointestinal Pathogen Panel, PCR, Feces

Useful For

Rapid detection of gastrointestinal infections caused by:

-Campylobacter species (Campylobacter jejuni/Campylobacter coli/Campylobacter upsaliensis)

-Clostridioides difficile toxin A/B

-Plesiomonas shigelloides

-Salmonella species

-Vibrio species (Vibrio parahaemolyticus, Vibrio vulnificus, Vibrio cholerae)

-Vibrio cholerae

-Yersinia species

-Enteroaggregative Escherichia coli (EAEC)

-Enteropathogenic E coli (EPEC)

-Enterotoxigenic E coli (ETEC)

-Shiga toxin

-E coli O157

-Shigella/Enteroinvasive E coli (EIEC)

-Cryptosporidium species

-Cyclospora cayetanensis

-Entamoeba histolytica

-Giardia

-Adenovirus F 40/41

-Astrovirus

-Norovirus GI/GII

-Rotavirus A

-Sapovirus

 

This test is not recommended as a test of cure.

Highlights

The FilmArray gastrointestinal panel is a multiplex polymerase chain reaction (PCR) test capable of qualitatively detecting DNA or RNA of 22 pathogens (bacteria, parasites, and viruses) in approximately 1 hour from feces in Cary Blair transport medium.

 

This test provides diagnosis of infections caused by Campylobacter species, Clostridioides difficile (formerly Clostridium difficile), Plesiomonas shigelloides, Salmonella species, Vibrio species, Vibrio cholerae, Yersinia species, enteroaggregative Escherichia coli, enteropathogenic E coli, enterotoxigenic E coli, Shiga toxin-producing E. coli, E. coli O157, Shigella/Enteroinvasive E coli, Cryptosporidium species, Cyclospora cayetanensis, Entamoeba histolytica, Giardia lamblia, adenovirus F 40/41, astrovirus, norovirus, rotavirus, and sapovirus.

Method Name

Multiplex Polymerase Chain Reaction (PCR)

Reporting Name

GI Pathogen Panel, PCR, F

Specimen Type

Fecal


Ordering Guidance


It is not recommended that the following tests be concomitantly ordered if this test is ordered:

-VIBC / Vibrio Culture, Feces

-ROTA / Rotavirus Antigen, Feces

-LADV / Adenovirus, Molecular Detection, PCR, Varies

-GIAR / Giardia Antigen, Feces

-CRYPS / Cryptosporidium Antigen, Feces

-CYCL / Cyclospora Stain, Feces

-STL / Enteric Pathogens Culture, Feces

-CAMPC / Campylobacter Culture, Feces

-SHIGC / Shigella Culture, Feces

-SALMC / Salmonella Culture, Feces

-YERSC / Yersinia Culture, Feces

-E157C / Escherichia coli O157:H7 Culture, Feces

-STFRP / Shiga Toxin, Molecular Detection, PCR, Feces

-CDPCR / Clostridioides difficile Toxin, PCR, Feces

-LNORO / Norovirus PCR, Molecular Detection, Feces



Additional Testing Requirements


In some cases, there may be local public health requirements that impact Mayo Clinic Laboratories (MCL) clients and require additional testing on specimens with positive results from this panel. Clients should familiarize themselves with local requirements. MCL recommends clients retain an aliquot of each specimen submitted for this test to perform additional testing themselves, as needed. If necessary, see Interpretation for detailed information about how to obtain this testing.



Shipping Instructions


Specimen must arrive within 4 days of collection.

Do not freeze. Testing will be canceled on specimens received frozen.



Specimen Required


Supplies: Culture and Sensitivity Stool Transport Vial (T058)

Container/Tube:

Preferred: Specific modified Cary Blair transport system; see Additional Information for acceptable collection media

Acceptable: Approved Cary Blair transport system (15 mL of non-nutritive transport medium containing phenol red as a pH indicator)

Specimen Volume: Representative portion of feces

Collection Instructions:

1. Collect fresh fecal specimen and submit 1 gram or 5 mL in container with transport medium.

2. Place feces in preservative within 2 hours of collection.

3. Submit preserved feces in original container. Do not aliquot.

4. If unpreserved specimens received, testing will be canceled.

Additional Information:

If collection media other than those listed is utilized, testing may be canceled. Media listed have been verified for use by Mayo Clinic Laboratories.

Modified Cary Blair media:

Preferred: Culture and Sensitivity Stool Transport Vial (T058)

Acceptable: Meridian Para-Pak C and S, Cardinal Health Culture and Sensitivity Stool transport Vial

Cary Blair media: Remel Cary Blair, Remel; Protocol Cary Blair


Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Fecal Ambient (preferred) 4 days
  Refrigerated  4 days

Reject Due To

Unapproved commercial transport media (eg, AlphaTec Enteric Transport Medium [ETM], Para-Pak Enteric Plus, Medical Chemical Corporation C and S Transport Medium [MCC])
Copan FecalSwab/ESwab
Products containing formalin (eg, Sodium Acetate-Acetic Acid Formalin fixative [SAF]; PolyVinyl Alcohol fixative [PVA]; EcoFix preservative)
Swabs (eg, Cary Blair gel swab; Rectal swab
Stool swab; Gel swab)
Endoscopy specimen
Unpreserved stool
Reject

Clinical Information

Acute diarrheal syndromes are usually self-limiting but may be complicated by dehydration, vomiting, and fever. Diagnostic testing and treatment may be required in some instances. Many bacterial enteric infections in the United States originate within the food supply chain. According to the CDC, in 2012 there were 19,531 laboratory-confirmed cases of infection with pathogens potentially transmitted through food in the United States. The numbers of infections, by pathogen, were as follows: Salmonella species (7800), Campylobacter species (6793), Shigella species (2138), Cryptosporidium species (1234), Shiga toxin-producing Escherichia coli non-O157 (551), Shiga toxin-producing E coli O157 (531), Vibrio species (193), Yersinia species (155), and Cyclospora cayetanensis (15). Giardia may also be transmitted through ingestion of contaminated food and water. There were 15,178 cases of giardiasis reported to the CDC in 2012. Since the clinical presentation may be very similar to many of these bacterial, viral, and parasitic pathogens, laboratory testing is required for definitive identification of the causative agent.

 

Rapid multiplex panel detection of the most common agents of bacterial, viral, and parasitic enteric infections directly from stool specimens is sensitive, specific, and provides same-day results, obviating the need for culture, antigen testing, microscopy, or individual nucleic acid amplification tests.

 

For other diagnostic tests that may be of value in evaluating patients with diarrhea the following are available:

-Parasitic Investigation of Stool Specimens Algorithm

-Laboratory Testing for Infectious Causes of Diarrhea

Reference Values

Negative (for all targets)

Interpretation

A negative result should not rule-out infection in patients with a high pretest probability for gastrointestinal infection. The assay does not test for all potential infectious agents of diarrheal disease.

 

Positive results do not distinguish between a viable or replicating organism and the presence of a nonviable organism or nucleic acid, nor do they exclude the potential for coinfection by organisms not contained within the panel.

 

Results of the panel are intended to aid in the diagnosis of illness and are meant to be used in conjunction with other clinical and epidemiological findings.

 

In some cases, there may be local public health requirements that impact Mayo Clinic Laboratories (MCL) clients and require additional testing on specimens with positive results from this panel. Clients should familiarize themselves with local requirements. MCL recommends clients retain an aliquot of each specimen submitted for this test to perform additional testing themselves, as needed. If necessary, selected add-on tests can be performed by MCL at an additional charge, as detailed below. Call 800-533-1710 within 4 days of specimen collection to request supplemental testing for positive test results:

 

Gastrointestinal pathogen panel positive for

Client action

Campylobacter species

Request add on test: CAMPC / Campylobacter Culture, Feces

Salmonella species

Request add on test: SALMC / Salmonella Culture, Feces

Shigella/Enteroinvasive E coli

Request add on test: SHIGC / Shigella Culture, Feces (for the Shigella/Enteroinvasive E coli target, the culture will assess for Shigella species only)

Yersinia species

Request add on test: YERSC / Yersinia Culture, Feces

Shiga toxin-producing E coli

E coli O157

Request add on test: E157C / Escherichia coli O157:H7 Culture, Feces

 

MCL will report results to the client for additional cultures when ordered. If cultures are positive and the client needs the isolated organism (eg, Campylobacter, Salmonella, Shigella, Yersinia or Vibrio species, or E coli O157:H7) for submission to a public health laboratory, the client needs to call MCL and request that the isolates be returned to them (the client). The client will be responsible for submitting the isolates to the appropriate public health department. Positive culture results will also be reported via the Electronic Clinical Laboratory Reporting System.

 

Alternatively (not preferred), clients who want a patient specimen returned from MCL should call 800-533-1710 as soon as possible, at the latest within 96 hours of specimen collection, to request that MCL return an aliquot of the submitted specimen to them. Clients will be responsible for submitting specimens to appropriate public health departments.

Cautions

The detection of microbial DNA or RNA is dependent upon proper sample collection, handling, transportation, storage, and preparation. There is a risk of false-negative results due to the presence of strains with sequence variability or genetic rearrangements in the target regions of the assays.

 

Repeat testing should not be performed on specimens collected less than 7 days apart.

 

The presence of blood or mucous in the specimen may interfere with testing.

 

Aeromonas species are not detected by this panel but may be detected by tests: STL / Enteric Pathogens Culture, Feces or AERMC / Aeromonas Culture, Feces.

 

The following information is provided by the test manufacturer:

Cary Blair media, used for dilution and processing of clinical stools, is screened by manufacturers for viable organisms but may not be specifically tested for microbial nucleic acids. The presence of nucleic acids at levels that can be detected by the FilmArray GI Panel may lead to false positive test results.(BioFire Technical Notes FLM1-PRT-0239-01 and QS-339B-01)

 

Campylobacter species: Detects but does not differentiate Campylobacter jejuni, Campylobacter coli, and Campylobacter upsaliensis. Other species will not be detected. Helicobacter pullorum may cross react.

Clostridioides difficile: Detects but does not differentiate toxin A gene (tcdA) and toxin B gene (tcdB). A positive result may reflect asymptomatic carriage or C difficile-associated diarrhea.

Salmonella species: Detects but does not differentiate Salmonella enterica and Salmonella bongori. Cross-reactivity may occur with some strains of Escherichia coli, which have the cryptic ETT2 type-III secretion system.

Vibrio species: Detects but does not differentiate Vibrio parahaemolyticus and Vibrio vulnificus. The assay may also react with less common Vibrio species such as, Vibrio alginolyticus, Vibrio fluvialis, and Vibrio mimicus. The assay is not expected to detect rare species of Vibrio such as: Vibrio cincinnatiensis, Vibrio furnissii and Vibrio metschnikovii. Grimontia hollisae may cross react.

Vibrio cholerae: V cholerae is specifically reported when detected. V cholerae strains that do not carry the toxR gene or which carry highly divergent toxR genes may not be detected. Rare non-cholerae strains of Vibrio that have acquired the toxR gene may cross-react (eg, Vibrio harveyi, Vibrio mimicus, Vibrio alginolyticus, Vibrio vulnificus).

Yersinia species: Detects Yersinia enterocolitica but does not differentiate known serotypes or biotypes. Yersinia kristensenii, Yersinia frederiksenii, and Yersinia intermedia cross-react at high levels with Y enterocolitica; detection is reported to genus level only.

Diarrheagenic E coli: Detects genetic determinants associated with classic diarrheagenic E coli/Shigella pathotypes. Transfer of these genes between organisms has been documented; therefore, detected results for multiple diarrheagenic E coli/Shigella may be due to the presence of multiple pathotypes or a single strain containing the genes characteristic of multiple pathotypes.

Enteroaggregative E coli (EAEC): Detects but does not differentiate 2 gene targets typically associated with enteroaggregative E coli; the aggR regulatory gene and the putative outer membrane protein, aatA, both located on the partially conserved pAA plasmid. pAA is not present in all strains phenotypically identified as EAEC, and not all pAA plasmids carry aggR and aatA genes; therefore, the assay will not detect all members of this diverse pathotype but is likely to detect most pathogenic strains.

Enterotoxigenic E coli (ETEC): Detects but does not differentiate heat-labile (LT) enterotoxin (ltA) and 2 heat-stable (ST) enterotoxin variants (st1a and st1b). Cross-reactivity may occur with strains of Hafnia alvei, Citrobacter koseri, Citrobacter sedlakii, and Cedecea davisae. LT-II and the STB/ST2 toxins are not detected.

Enteropathogenic E coli (EPEC): Detects eae gene but does not differentiate typical and atypical EPEC. The LEE pathogenicity island, which includes the eae gene, is also found in some Shiga toxin-producing E coli (STEC; O157 and non-O157 strains). Therefore, the results of the eae assay (positive or negative) are only reported when STEC is not detected. When STEC is detected, EPEC will not be reported, regardless of the EPEC assay result. Consequently, the assay cannot distinguish between STEC containing eae and a coinfection of EPEC and STEC. Rare instances of other organisms carrying eae have been documented (eg, Aeromonas species, Citrobacter species, Escherichia albertii, Shigella boydii). Others assays target bfp to detect EPEC and, if positive, reflex to eae detection to characterize isolates as typical or atypical EPEC. The bfp gene is not used to detect EPEC in this assay. For the reasons described above, EPEC may be missed or overcalled.

Shiga toxin-producing E coli (STEC): Detects but does not differentiate Shiga toxin 1 (stx1) and Shiga toxin 2 (stx2) sequences. Shiga toxin-positive results indicate the likely presence of STEC. Rare instances of detection of Shiga-like toxin genes in other genera and species have been reported (eg, Aeromonas caviae, Acinetobacter haemolyticus, Shigella sonnei, Enterobacter cloacae, Citrobacter freundii, Klebsiella pneumoniae).

E coli O157: The E coli O157 assay is not reported as detected unless a Shiga-like toxin gene is also detected. The assay cannot distinguish between infections with a single toxigenic STEC O157 or rare coinfections of STEC (non-O157) with a stx1/stx2-negative E coli O157.

Shigella/Enteroinvasive E coli (EIEC): Detects but does not differentiate Shigella species from enteroinvasive E coli.

Cryptosporidium species: Detects but does not differentiate approximately 23 different Cryptosporidium species, including the most common species (eg, Cryptosporidium hominis and Cryptosporidium parvum), as well as less common species (eg, Cryptosporidium meleagridis, Cryptosporidium felis, Cryptosporidium canis, Cryptosporidium cuniculus, Cryptosporidium muris, and Cryptosporidium suis), but is not expected to detect the very rare species Cryptosporidium bovis, Cryptosporidium ryanae, and Cryptosporidium xiaoi.

Entamoeba histolytica: Detects E histolytica. Entamoeba dispar present in high levels may cross-react.

Giardia: Detects Giardia lamblia (also known as Giardia intestinalis, Giardia duodenalis). A very low frequency of cross-reactivity with the commensal microorganisms Bifidobacterium and Ruminococcus species was observed in the clinical evaluation.

Adenovirus F40/41: Detects but does not differentiate F40 and F41. Does not detect respiratory adenovirus species such as B, C, and E.

Astrovirus: Detects but does not differentiate 8 subtypes (HAstV1-8).

Norovirus GI/GII: Detects but does not differentiate GI and GII. Does not detect genogroup GIV, nonhuman genogroups, or closely related Caliciviruses.

Rotavirus: Detects all strains of rotavirus A. In silico sequence analysis indicates that these assays will not cross-react with rotavirus B and C, which are less common in human disease, or rotavirus D, E, and F, which have not been found in humans. Recent oral rotavirus A vaccines may result in patients passing the virus in stool and be detectable in stool polymerase chain reaction (PCR) testing. Contamination of specimens with vaccine can cause false-positive rotavirus PCR results. Specimens should not be collected or processed in areas that are exposed to rotavirus A vaccine material.

Sapovirus: Detects but does not differentiate genogroups I, II, IV, V. Genogroup III will not be detected.(FilmArray Gastrointestinal [GI] Panel. BioFire Diagnostics, LLC)

Clinical Reference

1. Khare R, Espy MJ, Cebelinski E, et al. Comparative evaluation of two commercial multiplex panels for detection of gastrointestinal pathogens by use of clinical stool specimens. J Clin Microbiol. 2014;52(10):3667-3673

2. Centers for Disease Control and Prevention. Incidence and trends of infection with pathogens transmitted commonly through food-foodborne diseases active surveillance network, 10 U.S. sites, 1996-2012. MMWR Morb Mortal Wkly Rep. 2013;62(15):283-287

3. Centers for Disease Control and Prevention. Summary of notifiable diseases-United States, 2012. MMWR Morb Mortal Wkly Rep. 2014;61(53):1-121

4. DuPont HL. Persistent diarrhea: A clinical review. JAMA. 2016;315(24):2712-2723. doi:10.1001/jama.2016.7833

5. Lawson PA, Citron DM, Tyrrell KL, Finegold SM. Reclassification of Clostridium difficile as Clostridioides difficile (Hall and O'Toole 1935) Prevot 1938. Anaerobe. 2016;40:95-99. doi:10.1016/j.anaerobe.2016.06.008

6. Oren A, Garrity GM. Validation List No. 169. List of new names and new combinations previously effectively, but not validly, published. Int J Syst Evol Microbiol. 2016;66(6):2456-2458. doi:10.1099/ijsem.0.001181

Method Description

The FilmArray GastrointestinaI Panel is a closed system that performs the chemistry required for isolation, amplification, and detection of nucleic acid from multiple viral, bacterial, and parasitic gastrointestinal pathogens from a single stool specimen of patients suspected to have a gastrointestinal infection. A panel contains reagents in freeze-dried form and is divided into discrete segments where the required chemical processes are carried out. Patient sample and hydration fluid are drawn by vacuum into the panel and then placed into the FilmArray instrument. The detection process operations are automated (nucleic acid purification, first-stage polymerase chain reaction [PCR], second-stage PCR, and melt analysis) and complete in about an hour in this closed system:

-Nucleic Acid Purification:

The sample is lysed by a combination of chemical and mechanical mechanisms and the liberated nucleic acid is captured, washed, and eluted using magnetic bead technology.

 

-First-Stage PCR:

A reverse transcription step is performed to convert viral RNA into complementary DNA prior to amplification. The purified nucleic acid solution is combined with a preheated master mix to initiate the reverse transcription step and subsequent thermocycling for multiplex PCR.

 

-Second-Stage PCR:

Products of first-stage PCR are diluted and mixed with fresh PCR reagents containing an intercalating fluorescent DNA dye (LCGreen Plus), which is distributed over the second-stage PCR array. The individual wells of the array contain primers for different assays (in triplicate) that target specific nucleic acid sequences from each of the pathogens detected, as well as control template material.

 

-DNA Melting Analysis:

Temperature is slowly increased and fluorescence in each well of the array is monitored and analyzed to generate a melt curve.

 

-Analysis of Melt Curves:

The software evaluates the DNA melt curve for each well to determine if a PCR product was present in that well. If the melt profile indicates the presence of a PCR product, then the analysis software calculates the melting temperature of the curve, which is then compared against the expected range for the assay. When the software determines that the melt curve is positive and in range, it is called positive. When it determines that the melt curve is negative or is not in the appropriate range, it is called negative.

 

-Analysis of Replicates:

Melt curves of each of the 3 replicates for each assay are evaluated to determine the assay result. For an assay to be called positive, at least 2 of the 3 associated melt curves must be called positive, and the temperature for at least 2 of the 3 positive melt curves must be similar (within 1 degree C). Assays that do not meet these criteria are called negative.(Instruction manual: FilmArray Gastrointestinal [GI] Panel CE IVD. BioFire Diagnostics, LLC; RFIT-PRT-0143-05, 05/2021)

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

87507

NY State Approved

Yes

Testing Algorithm

If positive for Vibrio species or Vibrio cholerae, a Vibrio culture will be performed at an additional charge.

 

The following algorithms are available:

-Parasitic Investigation of Stool Specimens Algorithm

-Laboratory Testing for Infectious Causes of Diarrhea

Day(s) Performed

Monday through Sunday

Report Available

1 to 2 days

Forms

If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-Gastroenterology and Hepatology Test Request (T728)

-Microbiology Test Request (T244)

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
VIBC Vibrio Culture, Stool Yes No