Review sheet Flashcards
On a serial dilution with the following tubes set up, 1:2, 1:4, 1:8, 1:16, 1:32, 1:64, 1:132, 1:264….
What would the titer be if no visible agglutination in the tube 1:132
1:16
If 0.1 ml of serum is diluted with 0.9 ml of diluent, what dilution of serum does this
represent?
1:10
How would you explain universal precautions
Universal precautions are a standard set of guidelines to prevent the transmission of bloodborne
pathogens from exposure to blood and other potentially infectious materials
If 1 mL of saline is added to 10 mL of serum, what does the 10 mL represent? The dilution of the
final dilution, the diluent, the solute, the total solution, or the inverse proportion
The solute (item being diluted)
Which series of dilutions would be best in order to make a 1:4000 dilution?
1:2, 1:2, 1:1000
How would you define the term affinity
Affinity is the strength required for an interaction between a site of antigen binding at an antibody
and an antigen epitope
What is the prozone
Antibody excess
How would you define a precipitation reaction
The interaction between the soluble antigen and antibody results in the formation of insoluble lattice
that forms precipitate out of the solution
An Ouchterlony immunodiffusion assay is set up and a line of precipitation is seen forming between
the antigen and antibody wells. The lines of precipitation formed by two adjacent antigen wells cross
each other, forming an X. The reaction described is called
Non Identity
How would you define an antibody titer
Antibody titer is a laboratory test that measures the level of antibodies in a blood sample. The
antibody level in the blood is a reflection of the body’s past experience or exposure to an antigen, or
something that the body does not recognize as self.
Series of dilutions.
What is the zone of equivalence
When the antibody and antigen are in equal parts and optimal for binding
What does the diameter of the precipitation ring correlate to in radial immunodiffusion
The larger the
diameter, the more reactivity
What is meant by the term avidity
Affinity- but more so, looking at the van der waals interactions and strength of binding
In an Ouchterlony immunodiffusion procedure, a continuous arc of precipitate is observed between
two adjacent wells. What type of reaction is this
Identity
What causes agglutination
Various methods of agglutination are used in diagnostic immunology and these include latex
agglutination, flocculation tests, direct bacterial agglutination, and hemagglutination. In latex
agglutination, many antibody molecules are bound to latex beads (particles), which increases the
number of antigen-binding sites
If an immunoassay is performed in the following manner to look for an antigen (Ag) in the patient
serum: Patient serum + labeled Ag + known antibody (Ab) are added together and incubated.
Unbound material is washed off. The amount of labeled Ag is then measured. What assay is
performed?
Competitive
An immunoassay is performed in the following way: Antigen is bound to a solid support. Patient
serum is added, and patient antibodies bind to the antigen. The well is washed, and enzyme-labeled
anti-immunoglobulin antibodies are added. The well is washed, and enzyme substrate is added.
Enzyme activity is determined. Which immunoassay is described?
Heterogenous EIA
How would you describe an Immunoelectrophoresis assay
Immunofixation electrophoresis (IFE) is a double-diffusion technique
Unknown antigen is electrophoresed, and then antibody is applied directly to the gel
Precipitates form where antigen–antibody combination has taken place in the gel
Technique is used with serum as the antigen to determine over- or underproduction of antibody types
What is the principle behind nephelomotry
Light scattered across particles- looking for concentration via absorbance
When performing a precipitation assay what would the soluble antibody react with
Soluble antigen
How would you describe a precipitation assay
solutions containing antibody and antigen, respectively, that when combined, create lattice structures
that precipitate out of solution and that are visually present
A serological test that uses red blood cells coated with exogenous antigens such as bacterial
polysaccharides as a method to detect patient antibodies against that exogenous antigen is called
Hemagglutination
When a patient’s red blood cells combine with anti-B typing serum to produce a positive result, this
reaction is known as
Hemagglutination
What is Coombs’ reagent used for
The Coombs Reagent (also known as anti-human globulin) is used to distinguish the presence or
absence of immunoglobulin on the surface of red blood cells
What would be the best test to determine evidence of hemolytic disease of the newborn?
DAT
What is the characteristic of a noncompetitive enzyme immunoassays
Antibody is first passively absorbed to a solid phase
Unknown patient antigen is allowed to react with and be captured by the antibody
After washing to remove unbound antigen, a second antibody with a label is added to the reaction
Which antibody class may require the use of an enhancement technique to visualize the reaction?
IgG
In a precipitation reaction, how can the ideal antibody be characterized?
High Affinity and Avidity
What is meant by the term postzone
Antigen excess
In a capture assay to determine the presence of a viral antigen in a patient sample, what would be on
solid phase?
Antibody
Which assay poses the greatest risk of exposure to biohazards?
Use of radioisotopes
What is meant by “gating” in flow cytometry?
Separating cells into “like” squares
An intrinsic factor that can be measured by a flow cytometer
Forward-angle light scatter, (FSC) Side scatter (SSC)
When measuring by flow cytometry, what cells that are the smallest and have the least granules
Lymphocyte
How would you describe a test when lack of agglutination indicates the test is positive
Inhibition
In flow cytometry, if there are two light detectors, what does the amount of side scatter indicate?
Cell complexity
Identify the difference between batch and random-access analyzers
Batching is set 1,2,3,4- one test type. Random access allows for multiple test types and the
prioritization of stat samples to supersede the line
A test system is producing many false-positive results. What could cause this to occur
Low specificity
The lowest measurable amount of an analyte is called
LoQ, limit of qualification, limit of detection LoD
How would you determine a reference interval
Observe the mean, have an expected standard deviation range
The ability to consistently reproduce the same result on repeated testing of the same sample is called
Precision
Which is an advantage of automated testing in a clinical immunology laboratory?
Faster turn around time- less exposure to infectious agents
In flow cytometry, forward scatter provides a measure of
Measure of the relative cell size
How would you define the term accuracy
How close a measured value is to the true value
