Immunology- Labeled Assays

An additional advantage of an indirect assay is that

- it amplifies the reaction and makes the assay more sensitive -it allows for the determination of the class of the antibody that is bound

An indirect radioimmunoassay uses a different second antibody-binding step because of the radiolabel, but the same antibody binding step as

-an indirect enzyme immunoassay -an indirect fluorescent immunoassay -a capture assay

The presence of human heterophilic antibody is

-difficult to predict -the result of the patients interactions with animals of the species used to make the antibody in the assay -can cause false positive reactions in capture assays

HAMA

-is a human anti-mouse antibody -can cause false positives in capture immunoassays

In a sandwhich assay

-the antibody is sandwiched between a capture antigen and a labeled antigen -the antigen is sandwiched between a capture antibody and a labeled antibody

In a capture assay for IgM that reacts with rubella, an antibody human IgM binds the patient IgM, rubella antigen from the kit is added, and then an enzyme labeled antibody to rubella is added. What would happen to this assay if the patient had rheumatoid factor but no IgM antibodies to rubella?

The patient would appear positive for IgM rubella antibodies unless human IgG -that did not react with rubella was added as a specific blocker

Optical immunoassays are based on

a change in the color of light reflected from the surface when ag and ab are bound

For a small antigen with one epitope that is in the fluid phase, the best assay would be

a competitive assay

Which is a homogeneous assay?

a fluorescence polarization immunoassay

Which assay is the most sensitive?

a heterogenous labeled immunoassay

A fluorescent polarization assay is

a homogeneous labeled immunoassay

To measure the amount of a 200,000 MW tumor antigen in a patient's blood, the best assay is

a sandwich immunoassay

In a competitive immunoassay, the

amount of signal is inversely proportional to the amount of patient's antibody and can be determined from a standard curve

An indirect radioimmunoassay uses a different second antibody binding step because of the radiolabel but the same first antibody binding step as

an indirect enzyme immunoassay and an indirect fluorescent immunoassay

What two labeled immunoassays do not require instrumentation?

colloid immunoassay and optical immunoassay

In analysis of multiplex bead

one-color fluorescence is measured from the indirect immunoassay signal and one blended color is measured from the bead

Two assays used for point of care tests are

optical and colloid immunoassays

The first labeled assays developed were

radioimmunoassays

A western blot differs from a recombinant immunoblot because

the antigens on the nitrocellulose strip in the western blot have been electrophoresed and then blotted on to the blot and the recombinant immunoblot the antigens are just pipetted onto the blot

The assay that requires a trigger to measure the signal

the chemiluminescent assay

The kit for homogenous assay for meth comes with meth linked to G6P dehydrogenase, and antibody to the drug blocks the action of the enzyme when the patient's serum contains

the drug and there is more enzyme reactivity

To remove the effect of a patient's rheumatoid factor

the patients sample could be diluted in a buffer containing IgG that does not react with the test antigen

You have a patient who has rheumatoid factor. If you are performing an assay for various infectious diseases in which you capture the patients IgM, add the antigen, and then add a labeled antibody to the antigen....

the reactions with all antigens tested would be positive