Q: How do IMD-A systems detect microbes? A: Azbil BioVigilant’s IMD-A systems detect the presence of microbes by simultaneously measuring the size and intrinsic fluorescence of every particle in an aerosol sample as it is drawn through the instrument and interrogated by a laser. Microbes possess certain organic auto-fluorescent compounds necessary for cellular function, including NADH, riboflavin, and DPA (in the case of endospores). When these intrinsic fluorophores are excited by laser, they auto-fluoresce and this signal is measured. The IMD-A uses this fluorescence measurement as a critical metric within its proprietary and deterministic algorithms to differentiate a particle of biological origin (e.g. a bacterium) from an inert (e.g. dust) particle.