Patent ID: 7422870

Claim:
A method for counting bacteria in a clinical specimen that comprises Gram positive and Gram negative bacteria, the method comprising: preparing a first assay sample by dividing the clinical specimen into at least two parts and staining a first specimen part using a fluorescent dye, thereby producing a difference in fluorescent intensity between live bacteria and dead bacteria; preparing a second assay sample by staining all bacteria in a second specimen part using said fluorescent dye and a surface-active agent; detecting a first optical information from the first assay sample; detecting a second optical information from the second assay sample; classifying and counting dead bacteria in the first assay sample based on the first optical information; classifying and counting total bacteria in the second assay sample based on the second optical information; and calculating the number of live bacteria based on a total bacteria count obtained from the second assay sample and the dead bacteria count obtained from the first assay sample.