Immunoassays Flashcards

1
Q

who proposed that antigen combined with pre-existing side-chains on cell surfaces.

A

ehrlich

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the basis of immunoassays

A

specific binding between Ag and corresponding Ab

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what kind of bond is Ab-ag

A

non covalent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

is the binding of Ab and Ag reversible

A

yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

def? the initial force of attraction that exists between a single Fab site on an antibody molecule and a single epitope site on the corresponding antigen

A

affinity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

def? the overall strength of antigen-antibody binding and is the sum of the affinities of all the individual antibody-antigen combining sites.

A

avidity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is cross reactivity

A

ab reacting with ag that is structurally similar to the homologous ag

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what kind of immunochemical method is precipitation and light scattering

A

direct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what kind of immunochemical method is label methods

A

indirect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what immunoassays fall under the precipitation category

A

immunodiffusion and immunoelectrophoresis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what immunoassays fall under the light scattering category

A

nephelometry and turbidimetry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what immunoassays fall under the label method category

A

non competitive, competitive, heterogeneous, homogeneous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Immunoassays that detect antigen-antibody complex formation directly without labels are known as _____ or _______ immunoassays

A

direct; non labeled

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

is a label involved in precipitation immunoassays

A

no

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

are precipitation assays qualitative or quantitative

A

both

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

major components of direct assays

A

solution, gel, instrument

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

where are ag and ab in a direct immunoassay

A

diffusing into the solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what factors affect solubility

A

size, charge, temp, and solvent ionic strength

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

describe the prozone

A

ab is in excess

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

describe the zone of equivalence

A

ab and ag are equal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

describe the postzone

A

ag is in excess

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

does precipitate form in the prozone and postzone

A

no

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

A patient’s sample contains equal amount of Ab and Ag, but the reaction in a test system containing antigen is negative (no ppt). What has happened?

A

low specificity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

t or f: Precipitation reactions in gel are not commonly performed in the clinical laboratory today

A

T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what is gel made out of

A

dilute agarose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what kind of buffer is used for gel electrophoresis precipitation

A

aqueous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what kind of medium is gel considered

A

semisolid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what kind of assay do immune complexes separate more easily

A

gel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

in double diffusion radial immunodiffusion does the Ab or Ag diffuse into the gel

A

both

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

where is the Ag placed in double radial immunodiffusion

A

center well

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

where is the Ab placed in double radial immunodiffusion

A

in the wells surrounding the center well

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what kind of diffusion technique is radial immunodiffusion

A

double diffusion and single

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

is double radial immunodiffusion qualitative or quantitative

A

qualitative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what does single radial immunodiffusion quantitatively determine

A

Ag

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

where is the Ab in single radial immunodiffusion

A

incorporated into liquefied agar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

where is the Ag in single radial immunodiffusion

A

well

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

how is the amount of Ag quantified in radial immunodiffusion

A

by the amount of diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

how is the amount of Ag quantified in single radial immunodiffusion

A

diameter of ppt ring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what math equation can you use to determine conc of Ag in single radial diffusion

A

standard curve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

what are the Y and X axis of the standard curve

A

Y axis: diameter of the ring
X axis: conc of Ag

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Which part of the double immunodiffusion (RID) test system contains the antisera?

A

outer well

42
Q

Which part of the single immunodiffusion (RID) test system contains the antisera?

A

gel

43
Q

Why would we want to combine immunodiffusion with electrophoresis?
(electroimmunodiffusion)

A

speed and specificity

44
Q

what kind of diffusion technique is electroimmunodiffusion

A

single electro-immunodiffusion technique

45
Q

where is the Ab located in electroimmunodiffusion

A

in gel

46
Q

T or F: the pH of the electroimmunodiffusion gel is at a pH that immobilizes the Ab

A

T

47
Q

where is the Ag located in electroimmunodiffusion

A

wells

48
Q

what moves negatively charged antigens into the agar in electroimmunodiffusion

A

electric current

49
Q

what can happen if an electroimmunodiffusion gel is read during the initial phase and why

A

no ppt because there is excess Ag; the more the Ag migrate the more Ab they encounter

50
Q

do Ag migrate towards the anode or cathode in electroimmunodiffusion

A

anode

51
Q

what shape ppt forms in electroimmunodiffusion

A

rocket shaped

52
Q

what is proportional to the amount of Ag conc in electroimmunodiffusion

A

area under rocket shaped ppt

53
Q

what part of immunoelectrophoresis provides separation

A

Electrophoresis

54
Q

what part of immunoelectrophoresis provides detection

A

Immunoprecipitation

55
Q

what is the main advantages of immunoelectrophoresis

A

the number of antigens can be identified in serum and more specific

56
Q

what test would you use to find the identification and approximate quantization of various proteins present in the serum

A

immunoelectrophesis

57
Q

Immunoelectrophoresis is used in patients with suspected _______ and ________ gammopathies.

A

monoclonal and polyclonal

58
Q

what are the 2 phases of immuno electrophoresis

A

electrophoresis and fixation

59
Q

what is applied to the serum in immunofixation electrophoresis

A

serum

60
Q

do the serum proteins in immunofixation electrophoresis move towards the anode or cathode

A

cathode

61
Q

what is inoculated with the serum proteins in immunofixation electrophoresis

A

antiserum

62
Q

what is present if ppt forms in the fixation phase of immunization electrophoresis

A

Monoclonal proteins

63
Q

what is done to the gel after ppt forms

A

washed, stained, destained, and dried

64
Q

when would you use immunofixation electrophoresis in a clinical setting

A

identify abnormal bands seen on serum or urine protein electrophoresis

65
Q

what does immunofixation electrophoresis determine

A

type of Ab/immunoglobulin present

66
Q

what is an example of immunization electrophoresis

A

western blot

67
Q

what Two analytical methods are based on light scattering

A

Turbidity and nephroticelometery

68
Q

how is Ag conc determined using immunoturbidimetric assay

A

sample absorbance is compared to known Ag conc absorbance

69
Q

what do immuno complex cause to change in immunoturbidimetric assay

A

absorbance

70
Q

what does the angle of scattered light tell you

A

size of the immuno complexes and the wavelength of the incoming light

71
Q

what is a disadvantage of immunoturbidimetric assay

A

analytical device can be a source of errors

72
Q

what is measured in nephelometry

A

scattered light

73
Q

what is measured in turbidimetry

A

transmitted light

74
Q

in nephelometry what angle is scattered light measured at

A

90

75
Q

in turbidimetry what angle is transmitted light measured at

A

180

76
Q

what is the detector in nephelometry

A

PMT

77
Q

what is the detector in turbidimetry

A

photocell

78
Q

what do indirect/labeled immunoassays detect

A

labels attached to reactants

79
Q

advantages of radioisotopes

A

Flexibility
Sensitivity
Size

80
Q

disadvantages of radioisotopes

A

Toxicity
Shelf life
Disposal costs

81
Q

advantages of enzyme labels

A

Diversity
Amplification
Versatility

82
Q

Disadvantages of enzyme labels

A

Lability
Size
Heterogeneity

83
Q

advantages of florescent labels

A

Size
Specificity
Sensitivity

84
Q

Disadvantages of florescent labels

A

Hardware
Limited selection
Background

85
Q

an assay that combine chemiluminescence technique with immunochemical reactions

A

Chemiluminescence immunoassay

86
Q

what kind of labels does Chemiluminescence immunoassay

A

luminescent

87
Q

in a competitive immunoassay how much labeled ag is added

A

small amount

88
Q

how much pt ag is in a competitive immunoassay

A

lots

89
Q

the competitive ELISA relies on the competition between antigen of _____ and ______ antigen towards the _____ amount of antibodies.

A

interest, reference, limited

90
Q

what does noncompetitive immunoassays use excess of

A

ab

91
Q

in noncompetitive immunoassays the Concentration of antigen is directly proportional to

A

bound labeled ab

92
Q

what kind of ELISA is best for measuring low amounts of Ag

A

competive

93
Q

what kind of ELISA does not depend on the number of antigens present in a sample

A

noncompetitive

94
Q

what kind of assay requires a separation step and will produce an inverse relationship between the signal and analyte concentration

A

competitive heterogeneous immunoassay

95
Q

A noncompetitive heterogeneous immunoassay uses

A

Excess reagent and requires a separation step

96
Q

Ag∙Ab∙Ab* sandwich assay measures

A

Ab

97
Q

Ab∙Ag∙Ab* sandwich assay measures

A

Ag

98
Q

A laboratory is evaluating an enzyme-linked immuno sorbent assay (ELISA) for detection an antibody to cyclic citrullinated peptide (CCP), which is a marker for rheumatoid arthritis. The laboratory includes serum from healthy volunteers and patients with other connective tissue diseases in the evaluation. These specimens determine which factor of the assay:

A

Specificity

99
Q

What comprises the indicators system in an ELISA for detecting antibody?

A

Enzyme-conjugated antibody+chromogenic substrate

100
Q

What outcome results from improper washing of a tube or well after adding the enzyme-antibody conjugate in an ELISA system?

A

Result will be falsely increased