LOEFFLER'S METHYLENE BLUE, 500 mL

PRINCIPLE

Ziehl–Neelsen staining is used to diff erentiate acid-fast microorganisms. These microorganisms have a special lipid cell wall, which contains mycolic acid, amongst other substances. This enables the wall to resist destaining with acid-alcohol after staining with basic dyes such as fuchsine. The cell wall appears a reddish-pink colour, while the remainder of the microorganisms are stained with the counterstain, normally Methylene Blue. It is assumed that permeability through intact membranes may be an important component of the mechanism involved in the phenomenon of resistance to destaining by the acid-alcohol solution indicated above. While the classic Ziehl-Neelsen staining procedure specifi es the use of heat in the primary staining phase, the addition of a surface-active agent to a more concentrated Fuchsine dye makes it possible to perform cold staining. The remaining phases in the procedure are the same as those in the original Ziehl method. Although the mechanism of diff erentiation is not fully established, the method is fully accepted as a procedure for early diagnosis, as well as to provide information on the number of bacilli present in the sample. Acid-fast microorganisms are basically mycobacteria, although there are other microorganisms which also present this characteristic, such as the genus Nocardia and some parasites, such as Cryptosporidium

NTENDED USE

Family of in vitro diagnostic medical devices intended for detection of acid-fast bacteria, such as the Mycobacteria and Nocardia species and the cysts of Cryptosporidium and Isospora using the cold modifi ed Ziehl-Neelsen method. They are qualitative stains that provide information on the physiological or pathological state of the tissue sample when the staining obtained is interpreted by a trained professional. To obtain a diagnosis, the result is utilized alongside other information such as the patient’s medical history, physical status as well as other clinical and laboratory data obtained. For trained and specialized personne