Here we investigate real life utility and sensitivity of the microarray technique in a diagnostic set-up. We have established a protocol including pre-treatment, nucleic acid (NA) purification and Phi29amplification followed by microarray analysis of DNA and RNA viruses from a diverse set of clinical samples. We show that Phi29amplification generates enough material for successful identification by the Lawrence Livermore Microbial Detection Array (LLMDA) [19, 20] , demonstrating the potential of the microarray technique for broad-spectrum pathogen detection in clinical samples.