Lab Quiz 4 Flashcards
1
Q
Sensitivity
A
- what is the lowest concentration of a substance that can be measured
2
Q
Specificity
A
- does the assay detect one substance or cross-react and potentially detect others
3
Q
Three ways hormones are detected
A
- Bioassay
- Radioimmunology Assay (RIA)
- Enzyme-linked Immunosorbent Assay (ELISA)
4
Q
Bioassay
A
- an assay that uses live animals (in vivo) and tissue/cell culture (in vitro) that determines the biological activity of a substance
- qualitative measure
5
Q
Radioimmunology Assay (RIA)
A
- an assay that uses in vitro to detect the presence of an antigen using radioactive tagging, usually with high sensitivity and high specificity
- quantitative measure
6
Q
Enzyme-linked Immunology Assay (ELISA)
A
- uses antibodies and a color change to identify a substance
- it is qualitative, but can be quantitative
7
Q
Types of ELISA tests
A
- Sandwich ELISA
- Indirect ELISA
- Direct ELISA
- Competitive ELISA
8
Q
Sandwich ELISA
A
- add antibodies that will bind to whatever hormone you are trying to detect the presence of
- Add a sample of the hormone to bind
- Add more antibodies that are linked to an enzyme
- Add a substrate that is activated by an enzyme to cause the color change
- The wells that change in color have the presence of the hormone you are trying to measure
9
Q
Indirect ELISA
A
- wells are coated with antigens, a specific type of antibody
- Add the sample and allow antibodies to attach to antigen
- Add a secondary antibody that is tagged with an enzyme is added
- Add substrate to produce the color change
- Color change indicates presence of hormone
10
Q
Direct ELISA
A
- The ELISA plate is coated with antigens
- Only one antibody (and enzyme) detects the antigen
- The color change is directly related to the hormone concentration
11
Q
Competitive ELISA
A
- Usually used when antigen has a small number of binding sites
- Inhibitor antigens compete for binding site on the antibody
- color change is inversely represented by concentration
