acid-fast stain


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Related to acid-fast stain: Acid fast bacilli

stain

 [stān]
1. a substance used to impart color to tissues or cells, to facilitate microscopic study and identification.
2. an area of discoloration of the skin.
acid-fast stain a staining procedure for demonstrating acid-fast microorganisms.
differential stain one that facilitates differentiation of various elements in a specimen.
endogenous stain an intrinsic stain acquired during tooth development.
exogenous stain an intrinsic stain acquired after a tooth has erupted.
extrinsic stain a stain that can be removed from a tooth surface by polishing.
Giemsa stain a solution containing azure II-eosin, azure II-glycerin, and methanol; used for staining protozoan parasites such as Plasmodium and Trypanosoma, for Chlamydia, for differential staining of blood smears, and for viral inclusion bodies. Stained elements appear pink to purple to blue.
Gram stain a staining procedure in which bacteria are stained with crystal violet, treated with strong iodine solution, decolorized with ethanol or ethanol-acetone, and counterstained with a contrasting dye; those retaining the stain are called gram-positive, and those losing the stain but staining with the counterstain are called gram-negative.
hematoxylin and eosin stain a mixture of hematoxylin in distilled water and aqueous eosin solution, employed universally for routine examination of tissues.
intrinsic stain a stain that is within the enamel of a tooth and cannot be removed by polishing.
metachromatic stain one that produces in certain elements a color different from that of the stain itself.
nuclear stain one that selectively stains cell nuclei, generally a basic stain.
port-wine stain a persistent dark red to purple nevus flammeus that grows proportionately with the affected child and is usually found on the face. Initially it is macular, but the surface may develop angiomatous overgrowths with time. Port-wine stains often occur in association with other congenital abnormalities.
supravital stain a stain introduced in living tissue or cells that have been removed from the body.
tumor stain an area of increased density in a radiograph, due to collection of contrast material in distorted and abnormal vessels, prominent in the capillary and venous phases of arteriography, and presumed to indicate neoplasm.
vital stain a stain introduced into the living organism, and taken up selectively by various tissue or cellular elements.
Wright's stain a mixture of eosin and methylene blue, used for demonstrating blood cells and malarial parasites.

acid-fast stain

a method of staining used in bacteriology in which a smear on a slide is treated with carbol-fuchsin stain or auramine-rhodamine stain, decolorized with acid alcohol, and counterstained with methylene blue or potassium permanganate to identify acid-fast bacteria. Acid-fast organisms resist decolorization and appear red or yellow against a dark background when viewed under a microscope. The stain may be performed on any clinical specimen but is most commonly used in examining sputum for Mycobacterium tuberculosis, an acid-fast bacillus. See also Ziehl-Neelsen test.

acid-fast stain

A generic term for any of a number of special histologic stains—Ziehl-Neelsen, Kinyoun, hot carbolfuschin, et al—used to identify Mycobacterium spp,

Although there are other, non-pathogenic species of mycobacteria—which also stain with the acid fast technique present in normal flora—in the appropriate setting and in view of the increased prevalence of persons with immunosuppressed states, a positive acid-fast stain is presumptive evidence that the person has tuberculosis. Myocobacteria are acid-fast due to the mycolic acid content in the outer capsule; at an increased temperature, the basic fuchsin in phenol penetrates the capsular wax, hardens, and retains the dye during treatment with acid alcohol. Acid-fast stains may adhere to free hydroxy and carboxi- group of mycolic acid, explaining the acid-fastness of pine pollen, keratohyaline, lead inclusions, histoplasmosis, and lipofuchsin, as well as Nocardia spp and certain propionic bacteria. The Fite AFS uses a xylene-oil combination to partially ‘restore’ the acid-fastness lost in routine processing and is used to identify Mycobacterium leprae.

acid-fast stain

Microbiology A generic term for any of a number of special histologic stains–Ziehl-Neelsen, Kinyoun, hot carbolfuschin, et al, used to identify Mycobacterium spp

Acid-fast stain

A special stain done to microscopically identify the bacteria that cause tuberculosis.
Mentioned in: Sputum Culture
References in periodicals archive ?
Treatment may have suppressed the organism substantially so that numbers were too low to be identified on acid-fast stain or isolated on culture.
Morphologic characteristics, together with negative routine acid-fast stains (Ziehl-Neelsen, auramine-rhodamine), differentiate nocardia from mycobacteria.
Physicians need to alert the laboratory when they suspect Cyclospora so that a modified acid-fast stain can be performed.
Acid-fast stains were performed on biopsy sections.
Grocott methenamine-silver and acid-fast stains were negative for fungal and mycobacterial organisms, respectively.
Microbiology stainers provide high-quality Gram staining and different natural or fluorescent acid-fast stains for mycobacteria.
Currently, definitive diagnosis of mycobacteriosis in birds is accomplished by demonstrating organisms in organ biopsy or aspirate samples with acid-fast stains, culture, or molecular methods.
As with the other mycobacteria, on Ziehl-Neelsen and Kinyoun acid-fast stains the organisms are usually strongly acid-fast positive.