Short report

Verification of the Combimatrix influenza detection assay for the detection of influenza A subtype during the 2007–2008 influenza season in Toronto, Canada

Shelly Bolotin¹ , Ernesto Lombos¹ , Rani Yeung¹ , AliReza Eshaghi¹ , Joanne Blair¹ and Steven J Drews^1,2,3

¹  Ontario Agency for Health Protection and Promotion, 81 Resources Road, Toronto, Ontario, M9P 3T1, Canada

²  Department of Microbiology, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario, M5G 1X5, Canada

³  Department of Laboratory Medicine and Pathobiology, University of Toronto, 100 College Street, Room 110, Toronto, Ontario, M5G 1L5, Canada

author email corresponding author email

Virology Journal 2009, 6:37doi:10.1186/1743-422X-6-37

Published:	25 March 2009

Abstract

The increase in adamantine resistance in influenza A (H3N2) and the emergence of oseltamivir resistance in influenza A (H1N1) has necessitated the use of rapid methodologies to detect influenza subtype. The purpose of this study was to evaluate the CombiMatrix influenza detection system compared to the FDA approved Luminex Respiratory virus panel (RVP) assay for influenza A subtyping. Verification of the CombiMatrix influenza detection system was carried out using the Luminex RVP assay as a reference method. A limit of detection (LOD) series was performed using the Luminex and CombiMatrix systems with both influenza A H3N2 and H1N1 viruses. Seventy-five clinical specimens were used in the study. Of these, 16 were influenza A (H3N2) positive and five were influenza A (H1N1) positive. Fifty-four specimens were influenza A negative or "no call" (inconclusive) or could not be subtyped. The LOD of the Luminex RVP assay was found to be 0.3 TCID₅₀s/mL for influenza A (H3N2) and 16 TCID₅₀s/mL for influenza A (H1N1). The LOD of the CombiMatrix influenza detection system was 200 TCID₅₀s/mL for influenza A (H3N2) and 16 000 TCID₅₀s/mL for influenza A (H1N1). The sensitivity of the CombiMatrix influenza detection system was 95.2% and the specificity was 100%. The CombiMatrix influenza detection system is an effective methodology for influenza A subtype analysis, specifically in laboratories with a constrained budget or limited molecular capabilities.