Pathological Acid Fast Stain Reagents Phenol Free Fuchsin Staining Method

Pathological Acid Fast Stain (Phenol-free fuchsin staining method) Baso Clear Colourful Stains

Testing Principle

Acid-fast bacteria, such as Mycobacterium (e.g., tuberculosis bacilli), are difficult to stain due to a layer of lipid or lipoid membrane on their surface. However, once stained, they resist decolorization even when treated with acid-alcohol decolorizing solution. This characteristic is utilized by first staining with an enhanced staining solution, then treating with acid-alcohol decolorizer, and finally counterstaining. As a result, acid-fast bacteria retain the initial stain (red) and are easily identified. This product improves upon the traditional Ziehl-Neelsen acid-fast staining method by modifying the carbol fuchsin solution to exclude phenol (also known as carbolic acid), while still ensuring that acid-fast bacteria are vividly stained red. The counterstain uses malachite green, creating a sharp contrast between the red color of the acid-fast bacteria and the green background.

Stain Results
Against a light green background, acid-fast bacteria (e.g., tuberculosis bacilli) appear red, while other bacteria and cells appear green.

Mycobacterium tuberculosis is mostly rod-shaped and slightly curved. The width of the bacteria ranges from 0.3 to 0.6 µm, and the length varies between 0.5 to 8 µm, with most falling within 1.5 to 3.5 µm. A small number of longer bacteria may exhibit a spiral shape. In fresh specimens containing a high concentration of Mycobacterium tuberculosis, acid-fast staining and observation under a 100x oil immersion lens can reveal both individually dispersed bacteria and clusters or branching arrangements of bacteria.

Packaging Specification