histopath - Decalcification

To remove calcium ions from bone or calcified tissue

What is the purpose of decalcification?

Bones

What is the most common specimen used for decalcification?

Decalcification

Which step follows fixation in the decalcification process?

Exchange of calcium ions in acid solutions

What is the principle behind decalcification?

Hydrochloric acid

Which acid is considered a strong mineral acid used for decalcification?

Formic acid

Which weak acid is commonly used in laboratories for decalcification?

Versene (EDTA)

What is the most commonly used chelating agent for decalcification?

It preserves nucleic acids and tissue morphology

What is the advantage of using EDTA in decalcification?

Causes severe nuclear distortion and staining issues

What is a disadvantage of using nitric acid for decalcification?

7-8

What is the recommended pH range for EDTA in decalcification?

It stains poorly and macerates

What happens when a bone specimen is not properly fixed before decalcification?

Hydrochloric acid

What type of acid is Von Ebner’s Fluid based on?

Nitric acid

Which decalcifying agent is recommended for urgent biopsy processing?

Accelerates calcium removal by replacing ions

What is the function of ion exchange resin in decalcification?

Failure of nuclear chromatin to take up hematoxylin

Which staining issue is commonly caused by strong acids during decalcification?

2-7 days2-7 days

What is the decalcification time for Perenyi’s Fluid?

The extent of decalcification cannot be measured by a chemical test

What is a disadvantage of Von Ebner’s Fluid?

Can only process small bone fragments

What is a characteristic of microwave oven decalcification?

Thorough washing with water or neutralization

What is an important step after decalcification to ensure proper staining?

Nuclear staining is lost, and tissue distortion occurs

What happens if nitric acid is used for too long?

Suitable only for small fragments

What is the main limitation of using electrophoresis for decalcification?

To facilitate sectioning of hard tissues

What is the purpose of tissue softeners in histology?

4% aqueous phenol solution

What is a commonly used tissue softener?

Surface decalcification

Which technique is used to identify small calcium deposits in paraffin blocks?

Soak the tissue block in hydrochloric acid

What is the first step in surface decalcification?

Wash the block thoroughly with water

What must be done after surface decalcification to ensure proper staining?

Fluid access and agitation

What factor influences the rate of decalcification?

X-ray examination, Physical hardness test, Chemical test for residual calcium

Which decalcification end-point test is commonly used?

Acid removal

What is a key factor in tissue processing after decalcification?

It preserves nucleic acids and enzyme activit

Why is EDTA preferred for molecular techniques like PCR?