Special stains
Special stains are “special” because they are not routine. they are
applied to tissue sections in addition to hematoxylene and eosin
(H&E)-stained sections to answer questions that arise above and
beyond those that can be answered by interpreting H&E-stained
tissue morphology . the term “special stains” is of uncertain
provenance, but one can be certain that it began to be used after
1876 when H&E was introduced.
Pathogenic amoeba were rare in tissue
profiles and difficult to distinguish from
histocytes, even in special stains (x1000).
Eye exams often include using special stains on the cornea to
determine how much of the cornea has been damaged
The Periodic Acid
Schiff (PAS)
The Periodic Acid Schiff (PAS) for Fungus Stain Kit is
intended for use in histological demonstration of fungal
organisms in tissue sections. The PAS reaction is also
useful in the demonstration of lymphocytes and
mucopolysaccaharides. The staining patterns of the
lymphocytes are helpful in making therapeutic decisions
in established cases of lymphocytic luekemia.
Fungal Organisms: Magenta
PAS Positive Material: Magenta
Nuclei: Green/Blue
Leica Gomori's Trichome Special
Stain Kit (Green collagen)
Trichrome stains are used to stain and
identify muscle fibers, collagen and nuclei.
They can be used to contrast skeletal,
cardiac or smooth muscle.
The Gomori Trichrome is a simplification
of the more elaborate stains and combines
the plasma stain (chromotrope 2R) and
connective tissue with Gomori’s Green to
provide a brilliant contrasting stain.
Citrate Plus (10x)
HIER Solution
This is a unique citrate buffer designed to
significantly enhance immunohistochemical
staining with many commercially available
primary antibodies. Diluted 1:10 with
deionized or distilled water, this product is
easy to use and highly effective. Citrate Plus
(10X) can be used in a vegetable steamer,
autoclave, or pressure cooker. However, for
optimal results we recommend the autoclave
or pressure cooker.
The Rapid Giemsa
Stain Kit
The Rapid Giemsa Stain Kit is a high quality stain kit
specially formulated to provide rapid turnaround
Romanowsky type staining, on air-dried blood and
bone marrow smears, as well as non gynaecological
cytology samples such as: sputum, urine, fine needle
aspirates and tumour imprints. It can also be used to
stain micro organisms such as H. pylori, protozoa
and spermatozoa.
The easy to use kit consists of 3 x 500 mL bottles,
containing a fixing solution (Solution A), a red acid
dye (Solution B) and a blue basic dye (Solution C).
The kit also contains 5x pH 6.8 buffer tablets to
produce a buffered rinsing solution.
Leica Alcian Blue and
PAS Special Stain Kit
Combines the components of the Alcian Blue and Periodic Acid
Schiff (PAS) stain kits.
Alcian Blue is normally prepared at an acidic pH of 2.5 and is
used to identify acid mucopolysaccharides and acetic mucus.
-Excessive amounts of non acidic mucosubstances are seen in
mesotheliomas, certain amounts occur normally in blood vessel
walls but increase in early lesions of atherosclerosis.
PAS staining is mainly used for staining structures containing a
high proportion of carbohydrates such as glycogen, glycoproteins,
proteoglycans typically found in connective tissues, mucus and
basement membranes.
Often used to stain kidney biopsies, liver biopsies, certain
glycogen storage diseases in striated muscles and suspected fungal
infections.
Periodic Acid Special
Stain
Periodic Acid is a 0.5% aqueous
solution used to oxidize reactive
tissue elements to aldehydes
prior to treatment with Schiff
reagent.
This solution is prepared
immediately upon placement of
an order.
Special stains can be applied to cell biology and
histology. Some
useful applications are: (1) the determination of DNA and RNA
content,
(2) the mode of action of drugs, hormones or of potentially toxic food
additives, (3) metabolic biochemistry, (4) biochemistry of disease
processes, (5) primary sites of many metastatic tumors, (6) identification
of non-pigmented metastatic melanomas, (7) detection of early invading
tumors, (8) definition of the margins of surgically resected tumors,
(9) identification of Barr bodies, (10) staining cells in ways that can
be used as a basis for cell separation by appropriate instrumentation
(e.g., fluorescence), and (11) identification of micro-organisms (e.g.,
Cryptococcus neoformans, Helicobacter pylori). See Table 2.
“
Special stains remain an important tool for
many pathologists and technologists providing a
powerful complement to immunohistochemistry,
flow cytometry, in situ hybridization and other
diagnostic technologies that define a patient’s
medical profile.
”
Conclusion
Special stains belong to an assorted family of stains for microscopic
visualization and general identification of cells, tissues and
microorganisms. Special stains remain an important tool for many
pathologists and technologists providing a powerful complement to
immunohistochemistry, flow cytometry, in situ hybridization and other
diagnostic technologies that define a patient’s medical profile. With the
medical community demanding greater standardization and quality
control, special stain protocols have become increasingly automated
resulting in higher levels of productivity and flexibility. Automation is
no substitute for a solid understanding of the principles and practices
of a quality staining. We anticipate that this technology will continue to
evolve in the foreseeable future and expect it to form an integral part
of pathologic diagnosis. In a nutshell, this introduction was intended
to provide guidance to help interested readers acquire proficiency in
selecting and performing special stains faster than they might have
otherwise done.