The auramineâÂÂrhodamine stain (AR), also known as the Truant auramineâÂÂrhodamine stain, is a histological technique used to visualize acid-fast bacilli using fluorescence microscopy, notably species in the Mycobacterium genus. Acid-fast organisms display a reddish-yellow fluorescence. Although the auramineâÂÂrhodamine stain is not as specific for acid-fast organisms (e.g. Mycobacterium tuberculosis or Nocardia) as the ZiehlâÂÂNeelsen stain, it is more affordable and more sensitive, therefore it is often utilized as a screening tool.
AR stain is a mixture of auramine O and rhodamine B. It is carcinogenic.