STEPS IN TISSUE PROCESSING (IMPREGNATION AND Three methods used to process paraffin wax impregnation and
EMBEDDING) embedding:
By manual processing
Infiltration is the filling of tissue spaces and cavities with suitable By automatic processing
medium to avoid collapse of structure during cutting. -Makes use of an automatic tissue processor
- It fixes, dehydrates ,clears and infiltrates tissues
Its thoroughness depends on the thoroughness of dehydration and - Results in rapid diagnosis
clearing. - Only 2-3 changes of wax are required to remove the clearing
agent and properly impregnate the specimen. This is due to the
Infiltration (Impregnation) constant tissue agitation which accelerates and improves tissue
penetration
-The process whereby the clearing agent is completely removed -Dehydrating fluids should be change frequently
from the tissue and replaced by a medium that will completely fill o Dehydration is the most critical stage of tissue processing
all the tissue cavities o Inadequate dehydration is difficult to correct once the tissue
is in paraffin
-It gives a firm consistency to the specimen
-It allows easier handling and cutting of thin sections By vacuum embedding
-Involves the wax impregnation under negative atmospheric
pressure inside an embedding oven
Four types of tissue impregnation and embedding media o To hasten removal of air bubbles and clearing agent
from the tissue block.
Paraffin wax
• The simplest -Promotes a more rapid wax penetration of tissue
• The most common
• The best embedding medium used for routine tissue processing -Helps speed up wax impregnation and removal of residual
• Not recommended for fatty tissues & enzyme studies air bubbles
Recommended for:
o Urgent biopsies
o Delicate tissues such as lung,brain, connective tissues,decalcified
bones,eyes,spleen and central nervous system.
EMBEDDING) embedding:
By manual processing
Infiltration is the filling of tissue spaces and cavities with suitable By automatic processing
medium to avoid collapse of structure during cutting. -Makes use of an automatic tissue processor
- It fixes, dehydrates ,clears and infiltrates tissues
Its thoroughness depends on the thoroughness of dehydration and - Results in rapid diagnosis
clearing. - Only 2-3 changes of wax are required to remove the clearing
agent and properly impregnate the specimen. This is due to the
Infiltration (Impregnation) constant tissue agitation which accelerates and improves tissue
penetration
-The process whereby the clearing agent is completely removed -Dehydrating fluids should be change frequently
from the tissue and replaced by a medium that will completely fill o Dehydration is the most critical stage of tissue processing
all the tissue cavities o Inadequate dehydration is difficult to correct once the tissue
is in paraffin
-It gives a firm consistency to the specimen
-It allows easier handling and cutting of thin sections By vacuum embedding
-Involves the wax impregnation under negative atmospheric
pressure inside an embedding oven
Four types of tissue impregnation and embedding media o To hasten removal of air bubbles and clearing agent
from the tissue block.
Paraffin wax
• The simplest -Promotes a more rapid wax penetration of tissue
• The most common
• The best embedding medium used for routine tissue processing -Helps speed up wax impregnation and removal of residual
• Not recommended for fatty tissues & enzyme studies air bubbles
Recommended for:
o Urgent biopsies
o Delicate tissues such as lung,brain, connective tissues,decalcified
bones,eyes,spleen and central nervous system.
