Antigen-Antibody Reactions & Tests Flashcards
What is prozone?
Excess antibody
Pros have good bodies!
What is postzone?
Excess antigen
RIST and RAST are what type of tests?
Radioimmunoassays for detecting antibody and antigen
Radioimmunosorbent Test (RIST) tests for what?
Measures total IgE
Radioallergosorbent Test (RAST) tests for what?
Measures IgE to speific allergens
What could lead to a false positive result in ELISA?
Failure to wash between each step
What is the basic principle of Radial Immunodiffusion (RID)?
A circle of precipitated antigen and antibody forms, and continues to grow until equilibrium is reached.
What is the basic principle of double diffusion (ouchterlony)?
Determine relationship between antigens and antibodies by looking at double diffusion patterns.
Patterns: identity, non-identity, partial identity
What is the basic principle of immunoelectrophoresis? (IEP)
Gel diffusion + electrophoresis. Most commonly used to determine which heavy or light chains are involved.
What would you see in serum immunoelectrophoresis (IEP)?
Monoclonal gammopathies (single class and type of immunoglobulin)
What would you see in urine immunoelectrophoresis (IEP)?
Bence jones protein (monoclonal gammopathy)
What is the basic principle of immunofixation?
Protein electrophoresis + immunoprecipitation.
Very sensitive, easy to read.
Used to classify monoclonal gammopathies (determine heavy and light chains involved)
What is the basic principle of rocket immunoelectrophoresis? (Laurel)
Similar to radial immunodiffusion (RID) but electrophoresis is used to speed formation of precipitate.
» Cone shape area of precipitation forms that looks like a rocket
HIV testing, serum HcG, hepatitis antigen and antibody testing, and antibodies to bacteria and viruses are implemented with what type of immunoassay?
Enzyme immunoassay (EIA/ELISA)
What is the basic principle of enzyme multiplied immunoassay (EMIT)?
Used to measure concentrations of drugs and hormones
Positive test: color produced; drug in patient serum
Negative test: no color produced
What is the basic principle of nephelometry?
Determine concentration of antibody or complement using scattered light
What is the basic principle of fluorescence polarization immunoassay (FPIA)?
Add reagent antibody and fluorescent tagged antigen to patent serum
Serial dilutions: When does testing for infectious diseases happen?
On acute and convalescent specimens collected about 2 weeks apart
In a serial dilution, what fold in titer must you see for it to be clinically significant?
4-fold or 2 tube rise in titer for it to be clinically significant
What is the difference between SENSITIVITY and SPECIFICITY?
Sensitivity: Ability of a test to detect very small amounts of a substance; ability of a test to give positive results if patient has the disease.
Specificity: Ability of test to detect substance without interference; ability of test to give negative result if patient does not have disease
What immunology tests are more sensitive?
Non-Lattice (More sensitive) 0.001 mg/mL
- RIA (Radial immunoassay)
- EIA (Enzyme immunoassay)
- FIA (Fluorescent immunoassay)
- Nephelometry
What immunology tests are less sensitive?
Lattice –> Less Sensitive ~500 mg/ml
- Complement fixation
- Agglutination
- Flocculation / Precipitation
- Rocket Electrophoresis
- RID (Radial immunodiffusion)
- Ouchterlony (Double immunodiffusion)
- IFE (Immunofixation)
- IEP (Immunoelectrophoresis)
