Utility of rapid influenza antigen detection test for novel influenza virus(H1N1)

Abstract number: P1086

Acosta J., Otero J.R., Folgueira L.

Objectives: RT-PCR is the method of choice for diagnosis of pandemic H1N1 virus in respiratory samples; however such test cannot be readily performed in primary health care settings. It makes necessary to establish if currently commercially available rapid influenza diagnostic tests (RIDTs) can detect novel influenza A (H1N1) virus. The aim of this study was to compare the Directigen EZ Flu A+B® immunoassay with the real-time polymerase chain reaction (RT-PCR) assay developed by the Centers for Disease Control and Prevention (CDC) to detect pandemic influenza A/H1N1 2009 virus.

Methods: 140 samples (54 nasal aspirates and 86 nasopharyngeal swabs) collected from paediatric patients were submitted to the clinical virology lab for rapid influenza viruses testing during June, July and August. All tests were performed according to the manufacturer's instructions. Testing for pandemic influenza H1N1 2009 virus was performed using the CDC developed RT-PCR assay.

Results: Of 140 specimens, 71 (50.7%) were positive and 69 (49.3%) were negative by RT-PCR. Of the 71 specimens that tested positive by RT-PCR, 50 tested positive by RIDT for a test sensitivity of 70.4% and a positive predictive value of 100%. Of the 69 specimens that tested negative by RT-PCR, 69 tested negative by RIDT for a test specificity of 100% and a negative predictive value of 76.6%. The overall agreement between the two assays was 119/140 (85%).

Conclusions: RIDTs have lower sensitivity than RT-PCR or viral culture in the detection of seasonal influenza viruses. Several reports have shown that RIDTs have low sensitivity in detection pandemic influenza A/H1N1 2009 virus. In contrast, our data indicate that the sensitivity of BD Directigen EZ Flu A+B® influenza antigen detection was comparable to that of seasonal influenza previously reported for this assay, in samples collected from paediatric population.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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