HISTOPATH: FIXATION

The first and most critical step in histotechnology; Involves fixing or preserving fresh tissue for examination : prevents degeneration, decomposition, putrefaction, and distortion of tissues after removal from the body

• Decalcification
• Fixation

Is the art and science performed by histotechnologists to produce a tissue section of good quality that will enable the pathologist to diagnose the presence/absence of disease

• Histotechnology
• Moleculatechnology

Preserve the morphologic and chemical intergrity of the cell

• Primary Goal
• Secondary Goal

To harden and protect the tissue from the trauma of further handling

• Primary Goal
• Secondary Goal

Is a form of secondary fixation whereby a primarily fixed tissue is placed in aqueous solution of 2.5-3% potassium dichromate for 24 hours to act as mordant

• Post-chromatization
• Washing-out

Is the process of removing excess fixative from the tissue after fixation in order to improve staining and remove artifacts from the tissues

• Post-chromatization
• Washing-out

Used to remove chromates, formalin, and osmic acid

• Tap water
• 50-70% alcohol
• Alcoholic iodine

Used to wash out excess amount of picric acid

• Tap water
• 50-70% alcohol
• Alcoholic iodine

Used to remove excess mercuric fixative

• Tap water
• 50-70% alcohol
• Alcoholic iodine

The chemical constituent of the fixative is taken in and becomes part of the tissue; stability by forming cross-links

• Additive fixation
• Nonadditive fixation