Comparative analytical sensitivities of six rapid influenza A antigen detection test kits for detection of influenza A subtypes H1N1, H3N2 and H5N1.

BACKGROUND

Rapid and simple methods for diagnosing human influenza A (H5N1) disease urgently needed. The limited data so far suggest that the currently available rapid antigen detection kits have poor clinical sensitivity for diagnosis of human H5N1 disease.

OBJECTIVES

To compare the analytical sensitivity of six commercially available rapid antigen detection kits for the detection of "human" (subtypes H1N1, H3N2) and "avian" (subtype H5N1) influenza A viruses.

STUDY DESIGN

Six commercially available test kits for the detection of influenza A were investigated. Analytic sensitivity for the detection of two contemporary H1N1, two H3N2 and three H5N1 viruses was determined using virus culture as a reference method.

RESULTS AND CONCLUSIONS

Each test kit detected the H5N1 virus subtypes as efficiently as they detected conventional human viruses of subtypes H1N1 or H3N2. However, limits of detection of influenza viruses of all subtypes by antigen detection kits were >1000-fold lower than virus isolation. Thus, the reportedly poor clinical sensitivity of these antigen detection kits for diagnosis of patients with H5N1 disease is not due to a difference of sensitivity for detecting avian influenza H5N1 compared to human influenza viruses.