Test ID: 800071
Shiga Toxin Escherichia coli Antigen, Feces
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Rapid screening for EHEC serotypes including Escherichia coli O157:H7.
This test should serve as an adjunct to culture. However, in some situations when recovery of the organism by culture is not optimal (e.g. delayed transport of the specimen or transport of the specimen in preservative), or when isolation of the organism is not required for epidemiologic studies, this test may be considered as the preferred diagnostic method.
Method Name A short description of the method used to perform the test
Enzyme-Linked Immunosorbent Assay (ELISA)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Enteropathogenic E. coli
Escherichia Coli 0157 Stool Antigen Detection
Verotoxin Assay
JC/EHECTX
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Submit only 1 of the following specimens:
Preserved Stool
Container/Tube: Culture and sensitivity media
Specimen Volume: 10 g of diarrheal (liquid or loose gives optimal results) stool
Collection Instructions: See Stool Collection Information Sheet in Special Instructions.
Specimen Stability Information: Refrigerate/Ambient NO/Frozen NO
Unpreserved Stool
Collection Container/Tube: Stool container
Submission Container/Tube: Plastic container
Specimen Volume: 10 g of unpreserved diarrheal (liquid or loose gives optimal results) stool
Collection Instructions: See Stool Collection Information Sheet in Special Instructions.
Specimen Stability Information: Frozen/Refrigerate <48 hours OK/Ambient NO
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Specimens other than | Feces |
| Lipemia | NA |
| Icterus | NA |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Feces | Varies | |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Shiga toxin-producing Escherichia coli (STEC) have been recognized as agents of diarrhea and of sporadic cases and serious outbreaks of life-threatening hemorrhagic colitis and hemolytic uremic syndrome (HUS). Escherichia coli O157:H7 is the most frequently isolated enterohemorrhagic Escherichia coli (EHEC) serotype, but at least 50 serotypes have been implicated in the production of cytotoxins and development of complications.
Conventional testing methods for Escherichia coli O157: H7 involve isolation of the organism from fecal cultures followed by biochemical and immunologic confirmation. This method usually requires 72 hours for complete identification.
At this time, because antimicrobial therapy does not appear to be useful for treating the disease and may even increase the risk of HUS, recovery of Escherichia coli O157: H7 by culture for antimicrobial susceptibility testing is not necessary. The rapid diagnosis of Escherichia coli O157:H7 directly from fecal specimens is preferred to avoid unnecessary diagnostic procedures and inappropriate antimicrobial therapy and to identify common sources linked to transmission.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Negative
Interpretation Provides information to assist in interpretation of the test results
A positive result suggests the presence of Shiga-like toxin 1 or 2. It is recommended that all positive specimens be cultured to confirm the presence of enteropathogenic coli.
A negative result does not rule out the presence of enteropathogenic Escherichia coli; detectable antigen levels may not be produced until 3-6 days after the development of symptoms.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Antibiotic treatment prior to specimen collection may affect this assay; some antibiotics have the potential to destroy the cell wall component detected in this enzyme-linked immunosorbent assay (ELISA).
Supportive Data
This FDA-approved test was compared with Mayo's standard culture method for detecting Escherichia coli O157 using 46 reference specimens and 38 in-house specimens. The sensitivity (92%) and specificity (97%) of the assay was to equal culture. The assay had no cross reaction with stools containing other fecal pathogens including Aeromonas, Shigella sonnei, Beta strep (not Group A), Salmonella species (not typhi),Campylobacter jejuni , and yeast.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Karmali MA: Infection by verocytotoxin-producing Escherichia coli. Clin Microbiol Rev 1989;2:15-38
2. Karmali MA, Petric M, Lim C, et al: The association between idiopathic hemolytic uremic syndrome and infection by verotoxin-producing Escherichia coli. J Infect Dis 1985;151:775-782
3. Griffin PM, Ostroff SM, Tauxe RV, et al: Illnesses associated with Escherichia coli O157:H7 infections. A broad clinical spectrum. Ann Intern Med 1988;109:705-712
4. Wong CS, Jelacic S, Habeeb RL, et al: The risk of the hemolytic-uremic syndrome after antibiotic treatment of Escherichia coli O157:H7 infections. N Engl J Med 2000;342:1930-1936
Method Description Describes how the test is performed and provides a method-specific reference
An ELISA microplate assay is performed using broth cultures (18-24 hours) of stool specimens placed in microwells coated with rabbit polyclonal anti-Shiga toxin 1 and anti-Shiga toxin 2. In the processing, horseradish peroxidase enzyme conjugate and substrate tetramethylbenzidine (TMB) are added and the developed yellow color is read with a spectrophotometer. Specimens with indeterminate results are repeat tested after overnight incubation in a broth culture. (O'Brien AD, Holmes RK: Shiga and Shiga-like toxins. Microbiol Rev 1987;51:206-220)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Saturday
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
87427
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| 800071 | Shiga Toxin E. coli Ag, F | 53946-0 |
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