CLEARING (LAB)

De-alcoholization

CLEARING other name

CLEARING

Alcohol or a dehydrating agent is removed from tissue

CHARACTERISTICS OF A GOOD CLEARING AGENT

Miscible with alcohol, to promote rapid removal of dehydrating agents

CHARACTERISTICS OF A GOOD CLEARING AGENT

Miscible and easily removed by paraffin wax/mounting medium. To facilitate impregnation and mounting of the section

CHARACTERISTICS OF A GOOD CLEARING AGENT

Not produce excessive shrinkage, hardening and damage

CHARACTERISTICS OF A GOOD CLEARING AGENT

Should not dissolve Aniline dyes, not quickly evaporates in water baths and makes tissue transparent

Xylene, Dioxane, Chloroform and Cedarwood

REAGENTS MISCIBLE WITH PARAFFIN

Xylene

REAGENTS MISCIBLE WITH CANADA BALSAM

Glycerin and Gum Syrup

REAGENTS MISCIBLE WITH WATER (IN FROZEN SECTIONS)

Xylene and Toluene

REAGENTS MISCIBLE WITH ABSOLUTE ALCOHOL AND PARAFFIN

Chloroform and Benzene

REAGENTS MISCIBLE WITH ABSOLUTE ALCOHOL

XYLENE (XYLOL)

• Colorless, commonly used in the histopathology lab.

• Usually has ½ to 1 hour clearing time.

XYLENE (XYLOL)

Used also for embedding and mounting procedures

XYLENE (XYLOL)

Not for nervous tissues and lymph nodes

TOLUENE

• Substitute for Xylene and Benzene for clearing both during embedding and mounting process

• Time recommended is 1-2 hours.

TOLUENE

Not carcinogenic.

TOLUENE

High concentrations emit fumes that are toxic upon prolonged exposure

BENZENE

For urgent biopsies (15-60 minutes)

BENZENE

Volatilizes rapidly in paraffin oven

BENZENE

Carcinogenic, May damage Bone Marrow (Aplastic Anemia)

CHLOROFORM

Slower in action than Xylene

CHLOROFORM

for tough tissues like the skin, fibroid and decalcified tissues

CHLOROFORM

for nervous tissue, lymph nodes and embryos

CHLOROFORM

toxic to the liver after prolonged inhalation

CHLOROFORM

Wax impregnation is slow.

CHLOROFORM

May attack the rubber seal used in vacuum impregnating bath

CEDARWOOD OIL

Doesn’t dissolve aniline Dyes

CEDARWOOD OIL

Recommended for Central Nervous system and cytological studies. (Smooth muscles and the skin)

CEDARWOOD OIL

Clears for both paraffin and celloidin sections during embedding process.

CEDARWOOD OIL

Becomes milky upon prolonged storage and should be filtered before use.

ANILINE OIL

Not normally utilized as a routine clearing agent

ANILINE OIL

Recommended for clearing embryos, insects and very delicate specimens