testing has long been an important part of
diagnostic tests in the clinical laboratory for viral and
bacterial diseases.
Serologic
this testing is done in many
areas of the clinical laboratory—microbiology, chemistry,
toxicology, immunology, hematology, surgical pathology,
cytopathology, immunohematology (blood banking)- and
a great variety of specimens are tested.
immunologic
This is to make weaker solutions from
stronger solutions invarious laboratory procedures.
dilution
_____of blood is diluted to a total of _____with various reagents, and _____of this dilution is then analyzed for a particular chemical constituent
0.5mL of blood, 10mL variouss rgt, 1mL
used to correct for having used a
diluted sample in a determination rather than the
undiluted sample.
Dilution factor
method for determining the
concentration of a substance (e.g., antibody).The greatest
dilution of the sample that yields a positive result is the
end point.
Serial delutions
In obtaining specimens for serologic testing, it is important
to consider the phase of the disease and the condition of
the patient at the time of specimen collection. This is
especially important in assays for diagnosis of infectious
diseases. If serum is being tested for antibody levels with a
specific infectious organism, generally the blood should be
drawn during the acute phase of the illness—when the
disease is first discovered or suspected— and another sample
drawn during the convalescent phase, usually about 2 weeks
later. Accordingly, these samples are called acute and
convalescent serum. A di
ANTIBODY TESTING
defined
as the reciprocal of the highest dilution of the patient’s serum in
which the antibody is still detectable.
Antibody titer
false-negative result in
serological tests, like those for syphilis, caused by an
excess of antibodies that interfere with the formation of
antigen-antibody complexes, preventing a positive
reaction from being visualized.
Prozone phenomenon
This occurs when there are such
high levels of antibodies in a sample that they overwhelm
the available antigens, preventing them from binding and
forming the necessary lattice structure for a positive
result to be detected.
Prozone phenomenon
also known as antigen excess,
occurs when an excess of antigen in a sample prevents
antibody-antigen crosslinking, leading to a false-negative
result in immunoassays like agglutination or precipitation
tests.
POSTZONE PHENOMENON
refers to
the point where the optimal ratio of antigen and antibody
concentrations leads to the maximum amount of
precipitation, forming a visible lattice structure
ZONE OF EQUIVALENCE
At the zone of equivalence, the antigen and antibody
molecules bind together in a way that forms a cross-
linked network, or _____, which is insoluble and
precipitates out of solution.
Lattice
a graph that shows the relationship
between the amount of precipitation and the
concentration of antigen or antibody. The peak of the
curve represents the zone of equivalence.
Precipitin curve
the region in an immunoprecipitation
reaction where the concentration of antigen and antibody
are optimal, leading to maximal formation of immune
complexes. This zone is crucial for accurate laboratory
analysis and detection of antigen-antibody interactions
EQUIVALENCE ZONE
occurs when
a soluble antigen combines with its specific antibody,
forming an insoluble antigen-antibody complex that
precipitates out of solution.
precipitation
A quick qualitative test for the presence of
antigen-antibody complexes, where a ring of precipitate
forms at the interface of two liquid layers.
Ring test
Antigen and antibody di
Immunodiffusion
The reaction depends on the
presence of both antigen and antibody in optimal
concentrations.
Optimal proportions
The reaction depends on the
presence of both antigen and antibody in optimal
concentrations.
valency
the visible clumping
of particulate antigens (like bacteria or red blood cells)
when they react with specific antibodies, forming a lattice
-like structure.
Agglutination
Antibodies that cause agglutination are called
Agglutinins
Occurs when antibodies recognize
antigens naturally expressed by the target cell (e.g., red
blood cells).
Direct agglutination
Occurs when antibodies bind to
antigens that are not naturally expressed by the target cell
but are artificially attached to a carrier (e.g., latex particles).
Passive agglutination
