The LIVE BacLight™ Bacterial Gram Stain Kit provides a novel one-step fluorescence assay for the determination of gram sign in living bacteria. When gram negative and gram-positive bacterial are simultaneously stained with the membrane-permeant SYTO 9 dye and hexidium iodide, gram-negative bacteria fluoresce green and gram-positive bacteria fluoresce red.

Any physiological buffer between pH 7.0–8.0, including PBS, can be used to dilute the SYTO dyes for the staining solution.