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Public Health
Laboratory Testing

Influenza Subtyping

Influenza Subtyping

PHEL Order Choice #: 90798

Synonyms: Influenza A/B Subtyping test, Influenza Virus RT-PCR Typing

Submission Form: SRD-1

Program: Virology

Unit: Molecular

Use: Surveillance

Method: RT-PCR

Platform: ABI 7500 Fast Dx

Preferred Specimen Type: NP Swab

Accepted Specimen Types: Upper and lower respiratory tract clinical specimens, including nasopharyngeal swabs, nasal swabs, throat swabs, nasal aspirates, nasal washes, and dual nasopharyngeal/throat swabs, bronchoalveolar lavage (BAL)*, bronchial wash, and tracheal aspirates* from human patients with signs and symptoms of respiratory infection, or vital culture specimens. *Influenza A only. All swabs should be in 1-3ml of viral transport media (VTM). Swabs made of calcium alginate or that have cotton tips or wooden shafts are not acceptable.

Volume Requirements: Minimum volume VTM 500ul

Storage Temperature: Refrigerate specimens at 2-8C for up to 72 hours after collection. Specimens stored longer than 72 hours after collection should be frozen at -70C. Specimens frozen at -20C will be accepted although this can potentially impact specimen quality.

Transport Requirements: Ship refrigerated specimens on ice packs to maintain 2-8C. Ship frozen specimens on dry ice.

Influenza Test Collection Table

Type

Materials

Procedure

Nasal Swab

Dry Polyester Swab

Insert a dry polyester swab into the nostril. Using a gentle rotation, push the swab until resistance is met at the level of the turbinates (less than 1 inch into the nostril). Rotate the swab a few times against the nasal wall. Repeat in the other nostril using the same swab.
Put the tip of the swab into the plastic vial containing 3 ml of viral transport media and cut off the applicator stick. If a rapid antigen kit is going to be used, ideally two samples should be drawn in the manner described above. Package inserts accompanying the rapid antigen test kit should be followed when processing one of the two samples. If the test is positive, a second sample should be submitted to the Division of Public Health and Environmental Laboratories (PHEL) for additional testing to confirm the results of onsite testing.

Nasopharyngeal (NP) or Oropharyngeal (OP/throat) swab

Sterile Dacron or Nylon Swab
Do NOT use calcium alginate swabs or swabs with wooden sticks

Insert the swab through the nostril, parallel to the palate to the posterior nasopharynx (distance from the nostrils to the external opening of the ear). The swab should be left in place for a few seconds to absorb secretions. Slowly withdraw the swab with a rotating motion. Swab both nostrils with the same swab.
For OP swab, swab the posterior pharynx and tonsillar areas, avoiding the tongue. 
Put the tip of the swab into the plastic vial containing 3 ml of viral transport media and cut off the applicator stick.   
If a rapid antigen kit is going to be used, ideally two samples should be drawn in the manner described above. Package inserts accompanying the rapid antigen test kit should be followed when processing one of the two samples. If the test is positive, a second sample should be submitted to PHEL for additional testing to confirm the results of onsite testing.

Nasopharyngeal aspirates/wash

Suction apparatus
Sterile suction catheter
Sterile saline

Aspirate nasopharyngeal secretions through a catheter connected to a mucus trap and fitted to a vacuum source.
For NP wash have the patient sit with head tilted slightly backward.  Instill 1ml-1.5ml of nonbacteriostatic saline (pH 7.0) into one nostril. No saline is used for an aspirate.
Insert the catheter into the nostril parallel to the palate. Apply the vacuum and slowly withdrawn the catheter with a rotating motion. Mucus from the other nostril should be collected the same way. Specimen should be placed in a sterile vial.
If a rapid antigen kit is going to be used, ideally two samples should be drawn (e.g., one from each nostril) in the manner described above. Package inserts accompanying the rapid antigen test kit should be followed when processing one of the two samples. If the test is positive, a second sample should be submitted to PHEL for additional testing to confirm the results of onsite testing.