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Test Code LAB5490 Shiga Toxin, Molecular Detection, PCR, Feces

Additional Codes

SQ: STFRPM

MAYO: STFRP

 

Reporting Name

Shiga Toxin PCR, F

Useful For

Sensitive, specific, and rapid detection of the presence of Shiga toxin-producing organisms such as Escherichia coli O157:H7 and Shigella dysenteriae type 1 in stool

 

This test is not recommended as a test of cure.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Fecal


Additional Testing Requirements


In some cases, local public health requirements may impact Mayo Clinic Laboratories (MCL) clients and require additional testing on specimens with positive test results. MCL recommends clients retain an aliquot of each specimen for potential additional testing. Alternatively, if a specimen needs to be returned, clients must contact MCL within 96 hours of specimen collection. Clients will be responsible for submitting their specimens to appropriate public health departments.



Necessary Information


Specimen source is required.



Specimen Required


The high sensitivity of amplification by polymerase chain reaction requires the specimen to be processed in an environment in which contamination of the specimen by shiga toxin DNA is unlikely.

 

Submit only 1 of the following specimens:

 

Preferred:

Specimen Type: Preserved feces

Supplies: Culture and Sensitivity Stool Transport Vial (T058)

Container/Tube: Commercially available transport system specific for recovery of enteric pathogens from fecal specimens (15 mL of nonnutritive transport medium containing phenol red as a pH indicator, either Cary-Blair or Para-Pak C and S)

Specimen Volume: Representative portion of feces; 5 mL

Collection Instructions:

1. Collect fresh fecal specimen and submit in container with transport medium.

2. Within 2 hours of collection, place feces in preservative.

Specimen Stability Information: Ambient (preferred) 7 days/Refrigerated 7 days

 

Acceptable:

Specimen Type: Unpreserved feces

Supplies:

-Stool container, Small (Random), 4 oz (T288)

-Stool Collection Kit, Random (T635)

Container/Tube: Fecal container

Specimen Volume: Representative portion of feces

Collection Instructions: Collect fresh fecal specimen and submit representative sample in fecal container.

Specimen Stability Information: Refrigerated (preferred) 7 days/Frozen 7 days


Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time
Fecal Varies 7 days

Reference Values

Not applicable

Day(s) Performed

Monday through Sunday

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

87798

LOINC Code Information

Test ID Test Order Name Order LOINC Value
STFRP Shiga Toxin PCR, F 80679-4

 

Result ID Test Result Name Result LOINC Value
SRC59 Specimen Source 31208-2
56052 Result 80679-4

Method Description

This method employs a target-specific detection system, including polymerase chain reaction (PCR) primers and fluorescent resonance energy transfer (FRET) hybridization probes designed for the stx1 and stx2 genes. The LightCycler instrument amplifies and monitors target nucleic acid sequences by fluorescence during PCR cycling. This is an automated PCR system that can rapidly detect amplified product development. The detection of amplified products is based on the FRET principle. For FRET product detection, a hybridization probe with a donor fluorophore, fluorescein, on the 3' end is excited by an external light source, which emits light that is absorbed by a second hybridization probe with an acceptor fluorophore, LC-Red 640, at the 5' end. The acceptor fluorophore then emits a light of a different wavelength that is measured with a signal that is proportional to the amount of specific PCR product. The process is completed in a closed tube system.(Grys TE, Sloan LM, Rosenblatt JE, Patel R: Rapid and sensitive detection of Shiga toxin-producing Escherichia coli from nonenriched stool specimens by real-time PCR in comparison to enzyme immunoassay and culture. J Clin Microbiol. 2009;47[7]:2008-2012)

Report Available

1 to 2 days

Reject Due To

Formed feces Reject
Feces in gel transport medium Reject
Feces in EcoFix preservative Reject
Feces in formalin Reject
Feces in PVA fixative Reject
Preserved feces received frozen Reject

Method Name

Real-Time Polymerase Chain Reaction (PCR)

Testing Algorithm

For more information see Laboratory Testing for Infectious Causes of Diarrhea.

Forms

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

-Microbiology Test Request (T244)

-Gastroenterology and Hepatology Test Request (T728)

-Renal Diagnostics Test Request (T830)

-Coagulation Test Request (T753)

Secondary ID

35148