1. A discoloration.
2. A pigment or dye used in coloring microscopic objects and tissues.
3. To apply pigment or dye to a tissue or microscopic object or tissue.

acid stain

A chemical used to stain the cytoplasmic or basic components of cells.

acid-fast stain

A stain used in bacteriology, esp. for staining Mycobacterium tuberculosis, Nocardia, and other species. A special solution of carbolfuchsin is used, which the organism retains in spite of washing with the decolorizing agent acid alcohol.
SEE: Ziehl-Neelsen method

ATPase stain

A stain used to distinguish type 1 from type 2 muscle fibers microscopically. VAR: adenosine triphosphatase s.

auramine-Ziehl-Neelson stain

A histologic stain used to identify acid-fast bacilli, e.g., Mycobacterium tuberculosis.

basic stain

A chemical used to add pigment to the nuclear or acidic components of cells.

calcofluor white stain

A fluorescent stain used in microbiology to highlight fungi, including species of Pneumocystis.

Commission-Certified stain

A stain that has been certified by the Biological Stain Commission.

contrast stain

A stain used to color one part of a tissue or cell, unaffected when another part is stained by another color.

counter stain

SEE: counterstain

dental stain

A discoloration accumulating on the surface of teeth, dentures, or denture base material, most often attributed to the use of tea, coffee, or tobacco. Many stains contain calcium, carbon, copper, iron, nitrogen, oxygen, and sulfur. Stains may be intrinsic or extrinsic. Extrinsic stains of teeth can be removed, e.g., by brushing, rinsing, or sonication. Intrinsic stains cannot be removed by these methods.

differential stain

In bacteriology, a stain such as Gram stain that enables one to distinguish different types of bacteria.

double stain

A mixture of two contrasting dyes, usually an acid and a basic stain.

Feulgen stain

SEE: Feulgen stain

Giemsa stain

SEE: Giemsa stain

Gram stain

SEE: Gram stain

Grocott stain

A stain using silver ions to demonstrate fungal cell walls. The stain uses an argentaffin reaction to give the polysaccharide component of the cell wall a dark brown or black color.

hematoxylin-eosin stain

A common method of staining tissues for microscopic examination. It stains nuclei blue-black and cytoplasm pink.

hemosiderin stain

hemosiderin staining A discoloration of the skin where there has been significant bruising. It can happen after liposuction or other surgery. It typically resolves with time.
SEE: hemosiderin

intravital stain

A nontoxic dye that, when introduced into a metabolically active (living) organism, selectively stains certain cells or tissues.
SYN: SEE: vital stain

inversion stain

A basic stain that, when under the influence of a mordant, acts as an acid stain.

Jenner stain

SEE: Jenner stain

Leishman stain

SEE: Leishman, William Boog

metachromatic stain

A stain which causes cells or tissues to take on a color different from the stain itself.

Movat pentachrome stain

SEE: Movat pentachrome stain

neutral stain

A combination of an acid and a basic stain.

nonspecific stain

A dye added to a tissue specimen that binds to tissue indiscriminately, making it more difficult to distinguish one part from the next.

nuclear stain

A basic stain that colors cell nuclei, but does not stain structures in the cytoplasm.

Perls stain

SEE: Perls stain

phosphotungstic acid-hematoxylin stain

ABBR: PTAH A histological stain that binds to proteins, used primarily to stain skeletal muscles and mitochondria. It is also used to identify glial cells in the central nervous system and fibrin.

port-wine stain

SEE: Nevus flammeus.
SEE: nevus flammeus for illus.

special stain

A stain that highlights features of a cell or organism that cannot be readily identified with routine histological or microbiological staining techniques.

substantive stain

A stain that is directly absorbed by the tissues when they are immersed in the staining solution.

supravital stain

Stain that will color living cells or tissues that have been removed from the body.

trichrome stain

A three-colored tissue stain consisting of scarlet, phospho acid, and aniline blue dyes. It is used primarily in hepatic and renal biopsies to distinguish between collagen and smooth muscle fibers.

tumor stain

In arteriography, an abnormally dense area in a radiographical image caused by the collection of contrast medium in the vessels. This may be a sign of neoplastic growth.

viability stain

A cellular stain taken up only by living cells and used to demonstrate that those cells are enzymatically active.

vital stain

SEE: Intravital stain.

Wright stain

SEE: Wright stain