The ASM has published an interim algorithm providing guidance to clinical laboratories responsible for testing patients with respiratory illness for Influenza A, including H1N1
The document provides a detailed flowchart that guides microbiologists and physicians through patient assessment and differential diagnosis, and provides recommendations for confirmatory testing.
The algorithm focuses particular attention on collection of an optimal specimen, as this step determines the sensitivity and accuracy of the diagnosis.
The ASM recommends Nasopharyngeal (NP) Flocked Swabs, manufactured by Copan, as the specimen of choice for Influenza testing.
In addition to NP Flocked Swabs, NP aspirates, NP washes, or nasal aspirates are also recommended for testing.
The success of Flocked Swabs for Influenza testing is due to a brush-like action that dislodges large numbers of infected cells, and capillary hydraulics that draw liquid sample between the perpendicular fibres.
Flocked Swabs collect a large sample volume - almost four times more than foam swabs - and spontaneously release it into any test system.
Copan Flocked Swabs are easier to use, cause less patient discomfort and can be used for sample collection at remote centers, whereas NP aspirates and washes must be performed in a hospital setting with material cost that exceeds that of Flocked Swabs.
