techniques Flashcards
(26 cards)
agglutination
reactions between insoluble and soluble component
-takes place on the surface of something
2 main steps of agglutination
sensitization
lattice formation
sensitization stage
antigen and antibody combined through antigenic determinant sites
-rxn is rapid and reversible
lattice formation
crosslinking that form visible agglutination you see
too much antigen
post zone
too much antibody
pro zone
how to manipulate surface charge
add LIS - low ionic strength saline
albumin
enzymes
drawback when testing for IgM
rheumatoid factor
direct agglutination
antigens found on a particle
hemagglutination
particle involved is a RBC
passive/ indirect agglutination
particles are coated with antigen that is normally not found on them
reverse passive
antibody is coated on a particle
coagglutination
bacteria is inert particle to which a specific antibody is bound
-looking for antigen in patient serum
most common coagglutination
staph aureus – stick to protein A and look for presence of Antigen
one of first method used for hcg in urine
Agglutination inhabitation
how does Agglutination inhabitation work
negative reaction (no agglutination) is actually positive
-add patient serum (with antigen) add this to an Ab
if Ag is present on = Ag-ab response
-readd Ab coated with antigen– no attachment so negative rxn
what test use flocculation
RPR and VDRL (non-treponemal )
-this is a form of precipitation
antigen is lipid in nature– loose aggregates
precipitation
coming together of 2 soluble components to form insoluble complex
-less sensitive than agg
what type of rxn is precipitation
Secondary type reaction – because dependent on Ag-Ab coming together and then precipitating
affinity
initial attraction
avidity
strength of ag-ab
turbidity measurements
often measured how light is scattered in a spec
measures: amount of cloudiness (Ag-ab response)
no Ag-ab response= a lot of light coming through
nephelometry
Light scattered at an angle proportional to amount of Ag-Ab in a sample
-more complex= more scatter
detector at 90, 45 and straight line
what is beer’s law
Relationship between absorption of light with a solution and the concentration of the solution
-used in photometric methods
