Clearing

Clearing

Process of removing dehydrating agent from tissues to replace it with a medium that is miscible with both Paraffin wax and Mounting medium.

Incomplete clearing

uneven H&E staining and poor nuclear chromatin pattern

Prolonged clearing

can make tissues brittle

Xylene

routine clearing agent because it is fast acting

With rapid clearing time 30 mins – hours.

Xylene

NOT suited for nervous tissues and lymph nodes

It becomes milky when an Incompletely dehydrated tissue is immersed in it

Toluene

Substitute for xylene and benzene

Not as fast as xylene and benzene

Toluene

Acidifies in a partially filled vessel

Toxic on prolonged exposure

30 - hours

Duration for xylene

1-2 hours

Duration for Toluene

Benzene

Fast-acting

Suited for urgent biopsies

Doesn’t make tissues hard and brittle; minimum shrinkage

Benzene

Highly flammable and carcinogenic,

can damage BM leading to aplastic anemia

Chloroform

For rough tissues (skin, fibroid and decalcified tissues)

for nervous tissues, lymph nodes and embryos

Chloroform

Tissues tend to float, remedy wrap tissues with gauze to keep them at the bottom.

Chloroform

Toxic to the liver

Tissues do not become translucent

Use of this rgt can lead to wax deterioration

Cedarwood Oil

Extremely slow clearing agent

For cytological studies like smooth muscles of skin and for CNS tissues

Milky

Prolonged Storage for cedarwood oil

Aniline Oil

Recommended for clearing embryos, insects, and other very delicate specimens

Clove Oil

Tissues tend to become adulterated

Recommended for smooth muscles and skin

Causes minimum shrinkage

Limonene

Clearing Agent from citrus fruit

Carbon Tetrachloride

Similar to chloroform but cheaper

Toxic on prolonged exposure

Can cause tissue hardening

Methyl benzoate, Amyl acetate, Methyl salicylate

Slow acting clearing agents used for DOUBLE EMBEDDING

Oil of Bergamot and Oil of Origanum

For clear smooth muscles of the skin.

Oil of Wintergreen

For delicate tissues

Carbon Disulfide

For smooth muscles; with foul odor.

Carbon Xylene

For friable tissues.

Terpineol

To clear eye specimens.

Phenol

For smooth muscles

High Test Aviation Lead-free Gasoline

Excellent clearing agent

Terpenes

Found in essential oils originally derived from plants.

Orange Oil-based Clearing Agent

Offer the clearing action with the lowest hazard rating of all xylene alternatives.

Chlorinated Hydrocarbons

Disadvantage: Toxic

Coconut oil

Efficient substitute for xylene, as it is non-hazardous, less expensive, and causes less shrinkage of the tissue.

Bleached Palm Oil

Bio-degradable

Non-toxic

Nonflammable

Nonhazardous

Chloroform and Cedar Wood Oil

these clearing agents may be used for dense tissues like the uterus

N-butyl acetate

This reagent can be used as xylene substitute

Terpineol

has a faint odor and with low evaporation rate