Auramine–rhodamine stain is a fluorochrome acid-fast staining (AFB) method widely used in clinical microbiology, pathology, and infectious disease research for the rapid detection of acid-fast bacilli (AFB), particularly Mycobacterium tuberculosis complex and nontuberculous mycobacteria (NTM). The stain combines auramine O and rhodamine B, fluorochromes that are retained within the lipid-rich, mycolic acid-containing cell wall of acid-fast organisms after acid-alcohol decolorization. When examined using fluorescence microscopy, acid-fast bacilli appear as bright yellow to orange fluorescent rods against a dark background, enabling rapid examination of large specimen areas with greater sensitivity than conventional bright-field acid-fast stains such as Ziehl–Neelsen or Kinyoun methods. Consequently, auramine–rhodamine staining is widely used as the preferred initial screening method for acid-fast bacilli in laboratories equipped for fluorescence microscopy and is routinely applied to respiratory and non-respiratory clinical specimens in tuberculosis diagnostic laboratories and research settings.

Key Features

• High-Sensitivity Fluorescent Acid-Fast Stain : Detects Mycobacterium species and other strongly acid-fast microorganisms.

• Rapid Clinical Specimen Screening : Suitable for sputum, bronchoalveolar lavage, tissue sections, and other clinical specimens.

• High-Contrast Fluorescence : Acid-fast bacilli appear as bright yellow to orange fluorescent rods against a dark background, facilitating rapid visualization.

• Fluorescence Microscopy Compatible : Enables efficient examination of large smear areas.

• Ideal Initial Screening Method : Frequently used prior to confirmatory culture, nucleic acid amplification tests (NAATs), and species identification.

Typical Applications

• Tuberculosis (TB) laboratory diagnosis and AFB smear microscopy.

• Detection of nontuberculous mycobacteria (NTM).

• Clinical microbiology, pathology, and infectious disease research.

• Histopathology and cytology specimens requiring fluorescent AFB staining.

• Research involving Mycobacterium tuberculosis complex, nontuberculous mycobacteria, and other acid-fast microorganisms.