tetano
Editor, Senior Moderator
J Clin Microbiol. 2013 Nov 27. [Epub ahead of print]
Clinical and Virologic Factors Associated with Reduced Sensitivity of Rapid Influenza Diagnostic Tests in Hospitalized Elderly and Young Children.
Chan MC, Lee N, Ngai KL, Leung TF, Chan PK.
Source
Department of Microbiology.
Abstract
Rapid influenza diagnostic tests (RIDTs) are commonly used by clinicians to guide patient management. Data on sensitivity among hospitalized patients is limited. Here, we evaluated clinical and virologic factors affecting sensitivity of 2 commercially available RIDTs (BinaxNOW? Influenza A&B and QuickVue? Influenza A+B) on nasopharyngeal aspirate (NPA) specimens collected from the elderly and young children hospitalized for influenza. Influenza cases and age-matched negative controls were prospectively enrolled during the 2011/12 influenza season in Hong Kong. NPA specimens were collected at presentation before antiviral treatment. Real-time RT-PCR results were used as reference for sensitivity analysis. One hundred patients (57 influenza cases and 43 controls) were studied. Both RIDTs had 100% specificity. The sensitivity of BinaxNOW? Influenza A&B and QuickVue? Influenza A+B was 70% and 82%, respectively. For both tests, sensitivity was lower in cases with presentation time beyond 2 days of illness onset than within (50-71% versus 85-91%). There were trends toward lower sensitivity for influenza B than A (66-81% versus 76-84%), among young children than the elderly (63-78% versus 80-88%), and among pneumonic than non-pneumonic cases (75% versus 82-94%). Sensitivity of the RIDTs decreased with reducing NPA viral RNA level (5.6-15.0% reduction per 1 log decrease) which declined progressively after illness onset (Spearman's rho -0.47 [P<0.05] and -0.66 [P<0.001] for influenza A and B, respectively). Collectively, late presentation, low NPA viral load, and probably lower respiratory manifestation are factors associated with reduced sensitivity of RIDTs for diagnosing influenza in hospitalized patients. A negative RIDT result should be interpreted with caution.
PMID:
24285739
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/24285739
Clinical and Virologic Factors Associated with Reduced Sensitivity of Rapid Influenza Diagnostic Tests in Hospitalized Elderly and Young Children.
Chan MC, Lee N, Ngai KL, Leung TF, Chan PK.
Source
Department of Microbiology.
Abstract
Rapid influenza diagnostic tests (RIDTs) are commonly used by clinicians to guide patient management. Data on sensitivity among hospitalized patients is limited. Here, we evaluated clinical and virologic factors affecting sensitivity of 2 commercially available RIDTs (BinaxNOW? Influenza A&B and QuickVue? Influenza A+B) on nasopharyngeal aspirate (NPA) specimens collected from the elderly and young children hospitalized for influenza. Influenza cases and age-matched negative controls were prospectively enrolled during the 2011/12 influenza season in Hong Kong. NPA specimens were collected at presentation before antiviral treatment. Real-time RT-PCR results were used as reference for sensitivity analysis. One hundred patients (57 influenza cases and 43 controls) were studied. Both RIDTs had 100% specificity. The sensitivity of BinaxNOW? Influenza A&B and QuickVue? Influenza A+B was 70% and 82%, respectively. For both tests, sensitivity was lower in cases with presentation time beyond 2 days of illness onset than within (50-71% versus 85-91%). There were trends toward lower sensitivity for influenza B than A (66-81% versus 76-84%), among young children than the elderly (63-78% versus 80-88%), and among pneumonic than non-pneumonic cases (75% versus 82-94%). Sensitivity of the RIDTs decreased with reducing NPA viral RNA level (5.6-15.0% reduction per 1 log decrease) which declined progressively after illness onset (Spearman's rho -0.47 [P<0.05] and -0.66 [P<0.001] for influenza A and B, respectively). Collectively, late presentation, low NPA viral load, and probably lower respiratory manifestation are factors associated with reduced sensitivity of RIDTs for diagnosing influenza in hospitalized patients. A negative RIDT result should be interpreted with caution.
PMID:
24285739
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/24285739