Precipitation and Agglutination Flashcards
Measure of turbidity or cloudiness in a solution
Turbidimetry.
Principle of turbidimetry
Measures reduction in light intensity due to reflection, absorption, or scatter.
Unit of measurement in turbidimetry
Absorbance unit; ratio of incident light to transmitted light.
Principle of nephelometry
Measures light scattered at a specific angle.
Information derived from light scattering in nephelometry
Indicates solution’s concentration.
Concentration units in nephelometry
Milligrams per deciliter (mg/dL) or international units per milliliter (IU/mL).
Type of precipitation in a solid medium
Immunodiffusion.
Advantage of passive immunodiffusion
No electrical current, cheap, simple.
Disadvantage of passive immunodiffusion
Longer turnaround time (TAT).
Factors affecting rate of diffusion in immunodiffusion
Particle size, temperature, gel viscosity, hydration.
End product of Single Diffusion, Single Dimension (Oudin Test)- semiquantitative
Precipitin line.
Interpretation of line thickness in Single Diffusion, Single Dimension
Thicker line indicates higher antigen concentration.
Result of Single Diffusion, Double Dimension (Radial Immunodiffusion)
Precipitin ring.
Relationship between diameter and concentration in Radial Immunodiffusion
Diameter is directly proportional to concentration.
Method used in Radial Immunodiffusion for quantitative measurement
Fahey and McKelvey method (Kinetic Diffusion).
Time and measurement principle in Fahey and McKelvey method
19 hrs; diameter is proportional to log concentration.
Method used in Radial Immunodiffusion for end-point measurement
Mancini method.
Time for IgG and IgM in Mancini method
IgG = 24 hrs, IgM = 50-72 hrs.
Classification of diffusion in Double Diffusion, Double Dimension
Qualitative.
Diffusion directions in Double Diffusion, Double Dimension
Both horizontal and vertical through semisolid medium.
Result of identical epitopes in Double Diffusion, Double Dimension
Arc formation (serological identity).
Result of non-identical epitopes in Double Diffusion, Double Dimension
Crossed lines (non-identity).
Key characteristic of antigen in passive immunodiffusion
Soluble.
Technique used to separate molecules using electrical current
Electrophoresis.
Effect of direct current in electrophoresis
Forces antigen, antibody, or both to migrate.