Precipitation Flashcards
combination of SOLUBLE ANTIGENS and SOLUBLE ANTIBODIES to form insoluble complexes
Precipitation
Optimum precipitation occurs; number of multivalent sites of antigen and antibody are EQUAL
Zone of Equivalence
Presence of Excess Antibodies is called
Prozone
Remedy for Prozone phenomenon
Serum dilution
Presence of excess Antigen is called
Postzone
Remedy for Postzone phenomenon
Repeat test after a week
Prozone and Postzone phenomenon may lead to False ___ result
False negative
Measurement of Precipitation in Fluid Medium (2)
Turbidimetry
Nepholometry
Measurement of Precipitation in Fluid Medium
Has a principle of measuring light by BLOCKED LIGHT at a DIRECT LINE
Turbidimetry
Measurement of Precipitation in Fluid Medium
Has a principle of measuring light by SCATTERED LIGHT at AN ANGLE
Nephelometry
Which of the measurement of Precipitation in fluid medium is more sensitive
Turbidimetry (readings are taken before point of equivalence is reached)
Process of measuring precipitation without the used of electric current;
USES agar, gel, agarose
Passive immunodiffusion
Passive immunodiffusion:
Antibody is placed on the agarose
Antigen is placed on top, moves down the gels, and precipitation occurs
Single LINEAR Diffusion (Oudin)
Passive immmunodiffusion:
In Single Linear Diffusion the Antigen Concentration is based on the
Precipitation that moves down
A passive immunodiffusion by which the:
Antibody is uniformly distributed in the support gel
Antigen is placed a well cut into the gell
Area of rings is measured and is equal to Antigen Concentration
Single Radial Diffusion/ Radial Immunodiffusion
Single Radial Diffusion:
Antigen is diffused; Equivalence is reached and no further changes in diameter
Mancini / Endpoint Method
Single Radial Diffusion:
Mancini/Endpoint Method antigen is measured by
Square of the Diameter
Single Radial Diffusion:
Measurement of the precipitation is made before the point of equivalence has been reached; only occurs about 18 hrs / 24 hrs
Fahey / McKelvey / Kinetic Method
Single Radial Diffusion:
In Fahey /McKelvey Method the amount of precipitation if measured by the
Diameter by LOG OF ANTIGEN CONCENTRATION
A Passive immunodiffusion:
Allows diffusion of Antigen and antibody through semi solid medium in 2 dimensions
Double Radial Diffusion (Ouchterlony)
A passive immunodiffusion:
Antibody is placed on the central well
Antigen is placed on the surrounding
Double Radial Diffusion
In Double Radial Diffusion; Antigen is placed on the surrounding of the well
to determine if the antigens share identical epitope
Double Radial Immunodiffusion:
Serological Identity
Smooth arc
Double Radial Immunodiffusion:
Nonidentical
Crossed Lines
