Albert stain smear is a rapid differential staining technique primarily used to detect and identify Corynebacterium diphtheriae, the bacterium responsible for diphtheria.

The process highlights characteristic metachromatic granules (Babes-Ernst bodies) within the bacteria. When stained, the bacterial body appears light green, while the specialized storage granules stain an intense blue-black, creating a distinct "dashed" or "beaded" look under a microscope.

This simple smear test is a crucial diagnostic tool. It allows healthcare providers to quickly differentiate dangerous diphtheria-causing organisms from harmless throat bacteria, ensuring rapid medical intervention and timely treatment.