Differential staining
Encyclopedia
Differential Staining is a general term that can refer to a number of specific processes. Generally, it is used to describe staining processes which use more than one chemical stain
. Using multiple stains can better differentiate between different microorganisms or structures/cellular components of a single organism.
Differential Staining also describes medical process used to detect abnormalities in the proportion of different white blood cells in the blood
. The process or results are called a WBC differential. This test is useful because many diseases alter the proportion of certain white blood cells. By analyzing these differences in combination with a clinical exam and other lab tests, medical professionals can diagnose disease.
One commonly recognizable use of differential staining is the Gram stain. Gram staining uses two dyes: Crystal violet
and Fuchsin (the counterstain) to differentiate between Gram-positive
bacteria
(large Peptidoglycan
layer on outer surface of cell) and Gram-negative
bacteria.
Stain
A stain is a discoloration that can be clearly distinguished from the surface, material, or medium it is found upon. Stains are caused by the chemical or physical interaction of two dissimilar materials...
. Using multiple stains can better differentiate between different microorganisms or structures/cellular components of a single organism.
Differential Staining also describes medical process used to detect abnormalities in the proportion of different white blood cells in the blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
. The process or results are called a WBC differential. This test is useful because many diseases alter the proportion of certain white blood cells. By analyzing these differences in combination with a clinical exam and other lab tests, medical professionals can diagnose disease.
One commonly recognizable use of differential staining is the Gram stain. Gram staining uses two dyes: Crystal violet
Crystal violet
Crystal violet or Gentian violet is a triarylmethane dye. The dye is used as a histological stain and in Gram’s method of classifying bacteria. Crystal violet has antibacterial, antifungal, and anthelmintic properties and was formerly important as a topical antiseptic...
and Fuchsin (the counterstain) to differentiate between Gram-positive
Gram-positive
Gram-positive bacteria are those that are stained dark blue or violet by Gram staining. This is in contrast to Gram-negative bacteria, which cannot retain the crystal violet stain, instead taking up the counterstain and appearing red or pink...
bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
(large Peptidoglycan
Peptidoglycan
Peptidoglycan, also known as murein, is a polymer consisting of sugars and amino acids that forms a mesh-like layer outside the plasma membrane of bacteria , forming the cell wall. The sugar component consists of alternating residues of β- linked N-acetylglucosamine and N-acetylmuramic acid...
layer on outer surface of cell) and Gram-negative
Gram-negative
Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...
bacteria.
Further reading
- http://www.mansfield.ohio-state.edu/~sabedon/black03.htm#differential_stain Detailed Overview of staining
- http://www.uphs.upenn.edu/bugdrug/antibiotic_manual/Gram2.htm The Gram Stain Technique