SECTION ARTIFACTS AND REMEDY

              SECTION ARTIFACTS AND REMEDY

These deposits are the products of action of some reagents used in processing a section by simple deposition.

Formalin Pigment
It is formed in the tissue by the action of acid formaldehyde solution on
hemoglobin. Its formation can be limited by fixing in non-acid formaldehyde for example neutral buffered formalin.

Removal of formalin pigment
It can be removed by treating the section with alcoholic ammonia or alcoholic sodium or potassium hydroxide for 15mts to overnight. For unstained sections, treat the section with alcoholic picric acid.
Malarial Pigment
Malarial Pigment and bilharzial pigment are similar to formalin pigment in all their reaction but may be differentiated from the latter by their intracellular distribution.

Mercury Pigment
Tissues fixed in solution containing mercuric chloride contain a varying amount of dark brown on gray deposits of granular or irregular masses.

Removal of Mercury Pigment
1) Treat with 0.5% Iodine in 80% alcohol for 3 mins.
2) Rinse in tap water.
3) Treat with 3% Aqueous sodium thiosulphate until bleached (around 3 mins).
4) Wash in running water for 2 mins.

Chromatic deposits

If the tissues are not washed thoroughly in Water after fixation in chromatin containing fixatives, the chrome salts will react with dehydrating alcohol forming a yellow brown to black precipitate with the tissue.

Removal
By treating the section with 1% hydrochloric acid in 70% alcohol for 30mts.
Stain deposits

To avoid stain deposits, precipitate if any present in the staining solution should be removed by filtration, before adding the solution to the slide.

Paraffin Wax
Paraffin wax is sometimes retained in the section. It is removed by treatment
with xylene at 60°c, after thoroughly drying the section.



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