Clinics and Departments

Laboratory Services

Lab Dept:

Microbiology/Virology

Test Name:

RSV & INFLUENZA A, B PCR WITH REFLEX TO INFLUENZA A SUBTYPING

General Information

Lab Order Codes:

RIPST

Synonyms:

Influenza A, B and RSV PCR reflex to Influenza A subtyping; Flu A, B and RSV PCR with reflex to H1N1; Respiratory viruses, RSV and Influenza A, B PCR; PCR for RSV and Influenza A, B reflex to Influenza A subtyping; Virus, PCR for Influenza and RSV with reflex to H1N1, H3

CPT Codes:

87798 – Amplified probe technique, each organism (PCR)
87502 – Influenza virus, for multiple types of sub-types, multiplex reverse transcription and amplified probe technique, first 2 types or sub-types
87503 (if applicable) – each additional influenza sub-type

Test Includes:

Rapid detection of influenza virus types A and B and RSV in upper respiratory tract infections by RT-PCR (Reverse Transcription Polymerase Chain Reaction) Reflex to subtyping will be automatically performed on positive PCR results.

Logistics

Lab Testing Sections:

Molecular Diagnostics, Mpls campus only

Phone Numbers:

MIN Lab: 612-813-7103

STP Lab: 612-813-7103

Test Availability:

Specimens accepted daily, 24 hours

Turnaround Time:

12 – 24 hours

Special Instructions:

● Requisition must state specific site of specimen and date/time of collection.

Specimen

Specimen Type:

Bronchoalveolar lavage (BAL); Nasopharyngeal washings; nasopharyngeal (NP) aspirates; 2 flexible-shaft dacron NP swabs. Do not use calcium alginate swabs.

Container:

Sterile screw cap container; swab transport media

Caution:
containers with tubing tend to leak compromising the specimen.

Volume:

1 – 2 mL nasal washings, nasal aspirates or BAL; 2 NP swabs

Collection:

Nasopharyngeal Washings:
1.
Tilt patient’s head back at a 70 angle.
2.
Insert rubber bulb syringe containing 1 - 2 mL of sterile saline until it occludes the nostril.
3.
Collect specimen (Minimum: 1 mL) with one complete squeeze and release bulb.
4.
Repeat in other nostril.
5.
Dispense the specimen into a sterile screw cap container and transport to the lab immediately.

If specimen cannot be transported to the lab immediately, place 1 - 2 mL of specimen in viral transport media (VTM) and refrigerate.

Nasal Aspiratation:
1.
Prepare suction set up on low to medium suction.
2.
Wash hands and put on protective barriers (e.g., gloves, gown, mask).
3.
Place child supine and obtain assistant to hold child during procedure.
4.
Attach luki tube to suction tubing and #6 French suction catheter.
5.
Insert catheter into nostril and pharynx without applying suction.
6.
Apply suction as catheter is withdrawn. If necessary, suction 0.5 – 1 mL of normal saline through catheter in order to clear the catheter and increase the amount of specimen in the luki tube.
7.
Carefully transfer specimen to a screw cap container.

If specimen cannot be transported to the laboratory immediately, place 1 - 2 mL of specimen in viral transport media (VTM) and refrigerate.

NP swabs (2):
1.
Carefully insert a flexible-shaft dacron swab containing a dry tip into the nasopharyngeal cavity until resistance is encountered.
2.
Rotate the swab slowly on the nasopharyngeal membrane for 5 – 10 seconds to absorb secretions.
3.
Remove the swab, place in swab transport medium and send to the lab immediately.

If specimen cannot be transported to the laboratory immediately, cut swabs into viral transport media (VTM) and refrigerate.

Bronchoscopy:
1.
Specimen obtained by physician through the biopsy channel of the bronchoscope.
2.
Transfer 1 – 2 mL of sample into a luki tube or sterile container.

Special Processing:

Place specimen into viral transport media (M4VTM) upon arrival in laboratory.

Transport/Storage:

Transport to the Laboratory immediately to maintain specimen integrity. Specimens can be stored at refrigerated temperature (2 – 8 C) for up to 72 hours before processing.

Sample Rejection:

Specimen with a transit time exceeding 1 hour after collection without refrigeration; specimen not submitted in appropriate transport container; dry swabs; improperly labeled specimen; insufficient volume; leaking or non-sterile containers. If an unacceptable specimen is received, the patient’s caregiver will be notified and another specimen will be requested before the specimen is discarded.

Interpretive

Reference Range:

No RSV or Influenza A, B detected by PCR

Unresolved results due to PCR inhibition are inconclusive. Consider repeat collection if clinically indicated.

Limitations:

● Blood, excessive nasal secretions/mucus, decongestants and substances used to relieve nasal dryness or irritation may inhibit PCR and give unresolved results.
● There is a risk of false negative results if specimens are improperly collected, transported or stored.
● Low levels of virus shedding may yield a false negative result.

Methodology:

Reverse Transcription Polymerase Chain Reaction (RT - PCR)

References:

proFLU+ Instructions for Use, PIH34 V1.0 July 29, 2010, GenProbe Prodesse, Inc., W229 N1870 Westwood Drive, Waukesha, WI 53186

Miller, J Michael (1999) A Guide To Specimen Management in Clinical Microbiology, American Society for Microbiology, Washington DC, pg 100

Miller, J. Michael, Krisher, K. and Holmes, H.T. (2007) General Principles of Specimen Collection and Handling In P.R. Murray et al., (ed.), Manual of Clinical Microbiology, 9th edition, American Society for Microbiology, Washington, D.C., pg 50

Updates:

1/10/2011: Addition of BAL as a specimen type.
11/30/2011: CPT code update, previously reported as 87798x3. Updated pro-FLU and reference BAL validation completed 2011.



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