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.

This test is not recommended as a test of cure.

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

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

It is not recommended that VIBC / Vibrio Culture, Stool; ROTA / Rotavirus Antigen, Feces; LADV / Adenovirus, Molecular Detection, PCR; GIAR / Giardia Antigen, Feces; CRYPS / Cryptosporidium Antigen, Feces; CYCL / Cyclospora Stain; STL / Enteric Pathogens Culture, Stool; STFRP / Shiga Toxin, Molecular Detection, PCR, Feces; or CDFRP / Clostridium difficile Toxin, Molecular Detection, PCR, Feces be concomitantly ordered if this test is ordered. 

The following information is provided by the test manufacturer:

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.

Clostridium difficile: Detects but does not differentiate toxin A gene (tcdA) and toxin B gene (tcdB). A positive result may reflect asymptomatic carriage or Clostridium 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 (ie, Vibrio alginolyticus, Vibrio fluvialis, and Vibrio mimicus). Vibrio cholerae is specifically listed when detected. Grimontia hollisae may cross react.

Yersinia enterocolitica: Detects but does not differentiate known serotypes/biotypes. Yersinia kristensenii, Yersinia Frederiksenii, and Yersinia intermedia may cross-react at high levels.

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

Enteroaggregative Escherichia coli (EAEC): Detects but does not differentiate 2 gene targets typically associated with enteroaggregative Escherichia 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 Escherichia 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 Escherichia 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 Escherichia 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 co-infection 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 Escherichia 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 Shiga toxin-producing Escherichia coli. Rare instances of detection of Shiga-like toxin genes in other genera/species have been reported (eg, Aeromonas caviae, Acinetobacter haemolyticus, Shigella sonnei, Enterobacter cloacae, Citrobacter freundii, Klebsiella pneumoniae).

Escherichia coli O157: The Escherichia 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 co-infections of STEC (non-O157) with an stx1/stx2-negative Escherichia coli O157.

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