Chapter- 4 : Reagents (solution) used in clinical laboratories

Standard….

• In the preparation of secondary standard solutions the following points should be taken into consideration:
• Using analytical balance for weighing.
• Dissolving the weighted substance in the prescribed volume of solvent.
• Determining the exact concentration by comparison against a primary standard solution.
• Diluting stock secondary standard solutions using exact measurements.

4.7. Staining solutions

• Staining solutions are solutions that contain colored dyes.
• These solutions can contain basic, acidic or neutral dyes.
• Different stains are used in medical laboratories to give an artificial color for the substances to be identified from a given biological specimen (whole blood, body fluids, urine, etc.).
• The substances may be identified by their characteristic reaction with the staining solutions.

Staining …

• Based on their reaction, there are three kinds of stains:
• 1. Basic stains
• 2. Acidic stains
• 3. Neutral stains

Staining …

• 1. Basic Stains
• Are stains in which the colouring substance is contained in the base part of the stain and the acidic part is colourless.
• Example : Methylene blue stain, Safranin, Genetian violet, Carbolfuchsin etc.

Staining …

• 2. Acidic Stains
• Are stains in which the colouring substance is contained
• in the acidic part of the stain and the base part is colourless. E.g. eosin.
• 3. Neutral Stains
• Are stains in which the acidic and basic components of stains are coloured.
• Neutral dyes stain both nucleic acid and cytoplasm. e.g Giemsa’s stain, Wright’s stain.