Histology Laboratory

Special Stains

Hemotoxylin & Eosin (H & E) – The most widely used stain in medical diagnosis. This particular stain acts as the basis upon which further stains may be requested to confirm diagnosis. Nuclear proteins stain purple whereas cytoplasm and other tissue elements stain orange/red.

AFB – This is a stain used for Mycobacterium, Nocardia, endospores, and a few parasites. AFB staining may be an alternative stain when gram staining is inconclusive.

Alcian Blue/PAS (also known as AB/PAS) – The primary purpose of this stain is to view both neutral and acidic mucosubstances. Examples would be goblet cells of the small intestine or staining intervertebral discs.

Giemsa – Giemsa staining is very useful in identifying parasites or pathogenic bacteria. Giemsa staining is also widely used in blood films including peripheral blood smears and bone marrow aspirate slides.

GMS – This particular stain is used to identify opportunistic organisms primarily fungi and protozoa. GMS also stains connective tissue including basement membranes and endothelial cells.

Gram – Stains and differentiates both Gram (+) and Gram (-) bacteria. The particular modified stain that we use also stains the background of the specimen.

Iron (Prussian Blue) – This is a pigment stain which easily identifies the presence of iron deposits within samples. This becomes particularly useful when staining liver or bone marrow biopsies.

Periodic Acid Schiff (PAS) – This stains cells that are rich in carbohydrates. Positive cells are macrophages, connective tissue (collagen and basement membranes), and fungi. The benefit of staining a section with PAS is that the background is also stained and can be used for confirmation purposes.

Toluidine Blue – This is a metachromatic stain used in staining acidic mucins, nerve fibers, glial cells, and mast cells.

Trichrome – This is a connective tissue stain distinguishing collagen and muscle within a specimen.

Many other Special Stains are Available on Request