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Assay Sheet

Test ID

8100 Seasonal Influenza A H1 and H3 Subtyping RT-PCR

CPT Code

87798 (x2)

Clinical Utility

Influenza A viruses are medically important pathogens that cause significant morbidity and mortality throughout the world. The recent emergence of the 2009 H1N1 influenza A virus has lead to increased vigilance in monitoring these infections. Availability of several antiviral drugs coupled with differing resistance patterns between subtypes has led to a need for diagnostic testing that is able to rapidly and accurately subtype influenza A specimens. Utilizing molecular testing for subtyping enables the clinician to choose appropriate antiviral drug therapy as well as assisting in epidemiological tracking of influenza outbreaks.

Procedure

The assay consists of two real time RT- PCR reactions that allows for differentiation between seasonal influenza A H1 and influenza A H3.     

Extraction of influenza A nucleic acid from respiratory specimen is followed by reverse transcription of viral RNA, then amplification and detection of cDNA using real-time PCR. An internal control is added to ensure the extraction was performed correctly and the PCR reaction was not inhibited.

Note: The seasonal influenza A H1 assay will be negative if the patient is infected with 2009 H1N1. If confirmation of 2009 H1N1 infection is needed, ViraCor test code 7700 should be ordered.

Specimens

Bronchial Lavage/Bronchial Wash: 1 to 3 ml, collected in sterile, screw-cap tube; ship ambient.

Sputum: 1-2 ml submitted in a sterile, screw-top tube; ship ambient.

Throat Gargle:  Instruct patient to gargle with 2-3ml sterile saline. Expectorate into sterile cup, then transfer contents to sterile, screw-cap tube for shipment; ship ambient.

Upper respiratory aspirate (NP aspirate, nasal aspirate, tracheal aspirate, etc.): Instill 1 to 2 ml sterile saline into desired location and gently aspirate contents. Place collected fluid into sterile, screw-cap tube; ship ambient. 

Upper respiratory swab (NP swab, throat swab): Swab desired location with sterile, flexible shaft swab, preferably a flocked swab. Place swab into 1 to 2 ml sterile saline, M4, or viral transport media in sterile, screw-cap tube. Do not use calcium alginate swab or wood shafted swab; ship ambient.

All suction-type collection devices are inappropriate for specimen transport. Transfer specimen into sterile, leakproof tube for transport.

Other specimens may be accepted for testing; however the following comment will appear in the final report: "The clinical utility of this result has not yet been demonstrated in the peer reviewed literature and is therefore unknown." Call ViraCor for further information.

Causes for Rejection

Wood shafted swab, calcium alginate swab. Call ViraCor at 800-305-5198 if specimen is greater than 96 hrs old.

Specificity

The primers and probes used in this assay are specific for influenza A seasonal H1 and influenza A H3, respectively, based on similarity search algorithms. For the influenza A seasonal H1 portion of the assay, no cross reactivity was detected when tested against influenza A 2009 H1N1, influenza A H3, influenza B, RSV A, RSV B, parainfluenza 1, parainfluenza 2, parainfluenza 3, hMPV, rhinovirus, and adenovirus. Additionally, no cross reactivity was detected for the influenza A H3 portion of the assay when tested against influenza A seasonal H1, influenza A 2009 H1N1, influenza B, RSV A, RSV B, parainfluenza 1, parainfluenza 2, parainfluenza 3, hMPV, rhinovirus, and adenovirus.

Influenza A Seasonal h1 and influenza a h3 real time rt-pcr assay range

Limit of Detection (LOD): 500 copies/ml

Qualitative results (Positive/Not Detected) for both influenza A seasonal H1 and influenza A H3

Turnaround Time

Same day (within 8 to 12 hours of receiving specimen), Monday through Saturday

Reflex Testing Options Available

ViraCor 2009 H1N1 Influenza A Real-Time RT-PCR (7700)* Reflex to Seasonal Influenza A H1 & H3 Subtyping (8100)

Note: Go to www.viracor.com for additional respiratory virus reflex testing options.

*The FDA has issued Emergency Use Authorization for ViraCor 2009 H1N1 Influenza A Real-Time RT-PCR (Test Code 7700)

Shipping

Ship Monday through Friday. Friday shipments must be labeled for Saturday delivery. All specimens must be labeled with patient's name and collection date. Multiple tests can be run on one specimen. Ship specimens FedEx Priority Overnight® to:

The CPT codes provided are based on ViraCor's interpretation of the American Medical Association's Current Procedural Terminology (CPT) codes and are provided for informational purposes only. CPT coding is the sole responsibility of the billing party. Questions regarding coding should be addressed to your local Medicare carrier. ViraCor assumes no responsibility for billing errors due to reliance on the CPT codes illustrated in this material. PCR tests are performed pursuant to a license agreement with Roche Molecular Systems, Inc. This assay was developed and the performance characteristics were determined at ViraCor Laboratories. This test is performed in a CLIA certified laboratory. FDA approval is not required for the performance of this test.

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