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Test Code LAB7053 Norovirus RNA Detection by PCR

Performing Laboratory

Barnes-Jewish Hospital Laboratory

Methodology

  Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) using the Cepheid Xpert Norovirus assay performed on the GeneXpert System                                    

Specimen Requirements

Acceptable Specimens

Stool or rectal swab:  ≥1 mL of fresh liquid or non-formed stool  in a leakproof screw-capped, sterile container or 1 rectal ESwab per test request.

 

Unacceptable Specimen:
Solid or formed stool

Stool received in preservative
 

Collection Procedure:

 

Stool:

1. Collect ≥1 mL of fresh liquid or non-formed stool.
2. Place specimen in a leakproof screw-capped, sterile container. (Stool in container with preservative is not acceptable.)
3. Maintain sterility and transport promptly to the laboratory.
4. If transport is delayed, refrigerate specimen. If specimen will be in transport > 4 hours, transport with ice pack.

 

Rectal Swab:

1.  Pass ESwab beyond rectal sphincter.

2.  Rotate ESwab and withdraw.

3.  Return ESwab into transport tube following instructions on kit.

4.  Maintain sterility and transport promptly to the laboratory at room temperature only.
 

Notes:

1. Specimen source is required.
2. Specimen should not be collected following a barium enema.

3. Previously frozen specimen is acceptable.                                         

Day(s) Test Set Up

Monday through Sunday
                                     
Turnaround Time:
STAT: not available
Routine: 8 hours

Test Classification and CPT Coding

CPT Code:

87798 x2

Reference Values

Norovirus target RNA sequences are not detected (Negative).

Specimen Transport Temperature

Ambient OK (within 4 hours)

Refrigerate OK (within 48 hours)

Frozen OK

Additional Information

For BJH Laboratory Use Only

Minimum volume: 1 mL of fresh liquid or non-formed stool in leakproof screw-capped, sterile container.

 

Laboratory Processing Instructions

Test performed in BJH Molecualr Infectious Disease Laboratory

Limitations

Positive Xpert Norovirus results do not rule out other causes of infectious diarrhea.  Assay interference may be observed in the presence of Barium sulfate and Benzalkonium chloride.  Mutations or polymorphisms in primer or probe binding regions may affect detection of new or unknown norovirus variants resulting in a false negative result.  Results from the Xpert Norovirus Assay should be interpreted in conjunction with other laboratory and clinical data available to the clinician.