(A) Cluster analysis and heat map profile for 29 nasopharyngeal swab samples analyzed using the Virochip. Samples (y-axis) and probes on the Virochip designed a priori and derived from 3 influenza A strains (x-axis) are clustered using hierarchical clustering. The red color saturation indicates the magnitude of normalized probe intensity. (B) For each sample, the average normalized probe intensity for Virochip probes corresponding to human H1N1 influenza A (light blue) or swine H1N1 influenza A (dark blue) is shown. The asterisks denote samples for which the difference in probe intensity is significant by t-test analysis (p<0.05). Abbreviations: HA, hemagglutinin; NP, nucleoprotein; Cal, California; HRV, human rhinovirus; HPIV1, human parainfluenza virus 1; HCoV, human coronavirus; HPIV3, human parainfluenza virus 3; RSV, respiratory syncytial virus; Neg, negative.