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Imse Lab > Week 8: Rheumatoid Factor Latex Agglutination Test > Flashcards

Week 8: Rheumatoid Factor Latex Agglutination Test Flashcards

1
Q

Materials used

A

Rf latex suspension/ reagent
Black test card (reusable): to visualize agglutination
• 3 circles: positive control, negative control, rf latex reagent
Mechanical rotator
Positive and negative controls Disposable stirrer

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2
Q

Principle of the test

A

Passive or indirect agglutination reaction

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3
Q

A suspension of polystyrene latex particles sensitized with specially prepared human igG

A

Rheumatoid factor reagent

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4
Q

Uses carrier particles

A

Latex particle

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5
Q

Other carrier particles that can be used in passive agglutination

A

Erythrocytes
Gelatin
Charcoal

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6
Q

When polystyrene latex particle meets with the human igG in the serum it forms?

A

Agglutination

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7
Q

It is based on an immunological reaction between human igG bound to biologically inert latex particles and rheumatoid factors in the test specimen

A

Reagent

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8
Q

The rf latex reagent sensitivity has been adjusted to derect a minimum of __ rheumatoid factors

A

8 IU/ml

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9
Q

Sensitivity

A

8 IU/ml or above

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10
Q

Reagents

A

Rf latex reagent
Rf positive control serum
Rf negative control serum
Glycine saline buffer (20x)

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11
Q

It is a suspension of uniform polystyrene particles coated with igG in glycine buffer ph is 8.2

A

Rf latex reagent

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12
Q

Stabilized, pre-diluted human serum containing less than 8 IU/ml of rf (should not be reactive to rf)

A

Rf negative control serum

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13
Q

Stabilize pre-diluted human serum containing at least eight IU/ml of rf

A

Rf positive control serum

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14
Q

Only use in semiquantitative method
pH 8.2
+/-0.1M glycine
0.15M sodium chloride

A

Glycine saline buffer (20x)

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15
Q

If there is a positive result in the qualitative method the next step would be

A

Detecting the titer by the semi quantitative method

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16
Q

Qualitative method procedure or screening

A

7 steps

  1. Allow each component of the test gates reagents control to reach room temperature
  2. Gently shake the latex reagent using your palms to disperse the particles
  3. Place a drop of undiluted serum into the circles of the test slides
  4. Add one drop of rf latex reagent to the next drop of serum sample
  5. Spread the reagent and serum sample over the entire area of the test circle using a separate stirrer for each sample
  6. Gently tilt the test slide backwards and forwards or place in a mechanical rotator for 2 minutes 7. Observe and interpret the results
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17
Q

1st well

A

Positive control

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18
Q

2nd well

A

Negative control

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19
Q

3rd well

A

For serum sample

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20
Q

Positive and negative controls should be run at_____ to compare the results

A

Regular interval

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21
Q

Negative result shows or indicate

A

Uniform milky suspension with no agglutination observed in the rf negative control

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22
Q

Positive result a reaction is indicated by

A

Any observable agglutination in the reaction mixture

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23
Q

Semi quantitative method procedure or test can be performed in the same way as the qualitative test using dilutions of the serum in

A

Saline
Phosphate buffer saline or glycine saline

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24
Q

Dilutions of tube 1 2 3 4 and 5

A

1/2
1/4
1/8
1/6
1/32

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25
Q

Sample serum

A

100 ul

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26
Q

What tube does have sample serum only

A

Tube 1

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27
Q

How many ul of saline is used in tubes 1 to 5

A

100 ul

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28
Q

What is the sample volume of tube 1 to 5

A

50 ul

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29
Q

Titer of tube 1 to 5

A

16, 32, 64, 128, 256

8×Df= IU/ml

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30
Q

Reciprocal of the highest dilution showing macroscopic of glutination

A

Titer

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31
Q

If agglutination occurs in dilution 3 the titer is

A

64

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32
Q

Dilution factor is eight because this is the sensitivity of

A

Rf latex agglutination test

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33
Q

IU/ml of specimen =

A

IU/ml control specimen titer

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34
Q

The approximately rf level present in the sample may be obtained by

A

Multiplying the titer by the analytical sensitivity of rf latest reagent which is 8 IU/ml

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35
Q

Rheumatoid arthritis is another example of a

A

Systemic autoimmune disorder

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36
Q

How many percent does rheumatoid arthritis affects the adult population

A

0.5% to 1.0%

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37
Q

Prevalence of rheumatoid arthritis varies with

A

Ethnicity and geographic location

38
Q

Women are ___ as likely to be affected as men

A

3 times

39
Q

The prevalence of the disease is highest in women who are

A

More than 65 years of age

40
Q

Rheumatoid arthritis can be characterized as

A

Chronic, symmetric, and erosive arthritis of the peripheral joints

It can also affect multiple organs such as heart and the lungs

41
Q

Association of RA with more than ____ genetic regions have been discovered

A

30

42
Q

The strongest associations have been between a subset of patients with ra and specific ____ and ____.

A

HLA-DRB1 alleles or PTPN22 gene polymorphisms

43
Q

The strongest environmental risk factor for ra is believed to be

A

Cigarette smoking which doubles the risk of developing the disease

44
Q

The pathology of ra is caused by an inflammatory process that results in the

A

Destruction of bone and cartilage

45
Q

The ______ in rheumatoid joints show an increase in cell lining the synovial membrane and formation of a panus

A

Lesions

46
Q

Organized mass cell/ a sheet of inflammatory granulation tissue that grows into the joint space and invades the cartilage

A

Pannus

47
Q

Evidence of immunologic activity within the joint is the infiltration of the inflamed synovium with?
(Cells)

A

T and B lymphocytes
Plasma cells
Dendritic cells
Mast cells
Granulocytes

48
Q

What is the role of autoantibodies in the initiation of the inflammatory response

A

Not known

49
Q

Two key antibodies found in the disease are:

A

Rheumatoid factor
Anti–cyclic citrullinated peptide (anti-CCP)

50
Q

Rheumatoid factor is an antibody that is most often of the igM class and is directed against which portion of igG

A

FC Portion

51
Q

It has been postulated that rheumatoid factors may play a role in the pathogenesis of rheumatoid arthritis by increasing ___ and ___.

A

Macrophage activity and enhancing antigen presentation to T cells by apcs (antigenpresenting cells)

52
Q

In rheumatoid arthritis, autoantibodies such as rf and anti ccp are thought to combine with their specific antigen and resulting immune complexes become deposited in the joints resulting in what type of hypersensitivity reaction

A

Type 3 hypersensitivity reaction or immune complex

53
Q

What complement protein binds to the immune complexes, activating the classical component cascade?

A

C1

54
Q

During this process ___and ___ are generated, which act as chemotactic factors for neutrophils and macrophages

A

C3a and c5a

55
Q

It acts as a chemotactic factor for neutrophils and macrophages

A

C3a and c5a

56
Q

The continual presence of this cells (neutrophils and macrophages) and their associated cytokines leads to

A

Chronic inflammation which damages the synovium itself

57
Q

Diagnosis of rheumatoid arthritis is based on a combination of

A

Clinical manifestations
Radiographic findings and Laboratory testing

58
Q

It is the antibody that is most often tested to aid in making the initial diagnosis

A

Rf or rheumatoid factor

59
Q

The importance of testing for the presence of rf is also reflected in the fact that it is one of the classification criteria for

A

Rheumatoid arthritis

60
Q

It is an auto antibody that is usually in the igm class that reacts with the fc portion of igg

A

Rheumatoid factor

61
Q

Approximately _____of patients with rheumatoid arthritis test positive for rf

A

70% to 90% of patients

62
Q

A negative test or result does not rule out the presence of ra

A

True

63
Q

A positive test is not specific for RA because RF is also present in about _____ of healthy individuals and in _____ of those over the age of 65

A

5% of healthy individuals
10% to 25% of those over the age of 65

64
Q

Rf is present in about ___ in healthy individuals

A

5%

65
Q

Rf can be found in patients with other connective tissue diseases such as

A

Systemic lupus erythematosus Sjogren’s syndrome
Scleroderma
Mixed connective tissue disease
People with some chronic infections

66
Q

Manual agglutination test using __ or ___ have been used for many years to detect rf

A

Charcoal or latex particles coated with igG

67
Q

These test, however only detect the igM isotype found in about 75% of the patients

A

Manual agglutination tests

68
Q

Manual agglutination test only detect the

A

IgM isotype

69
Q

Igm isotype is found in about how many percent of patients

A

75%

70
Q

Manual agglutination tests have been largely replaced by automated methods. These have also a greater precision and sensitivity, can also detect other isotypes

These are the following:

A

Enzyme link immunosorbent assay chemiluminescence immunoassay Nephelometric methods

71
Q

Once a diagnosis of rheumatoid arthritis is made the most helpful test for following the progress of the disease are general indicators of inflammation, such as:

A

Measurement of erythrocyte sedimentation rate
C-reactive protein
Complement components

72
Q

What is the typical result of esr and crp

A

Elevated

73
Q

Resutls of the levels of serum complement components are

A

Normal or increased because of increased acute phase reactivity

74
Q

Levels of serum component complements are normal or increase because of increase

A

Acute-phase reactivity

75
Q

The result should be read in____ mixing the reagent on the slide

A

2 minutes after

76
Q

Existence of __ at high titers has not been encountered

A

Prozone

77
Q

Increased levels of rheumatoid factor may be around in some diseases other than rheumatoid arthritis such as

A

Mononucleosis or sarcoidosis
Lupus Erythematosus
Sjogren’s syndrome

78
Q

Certain patients with rheumatoid arthritis will not have the rf present in their serum

A

True

79
Q

Reagents are stable until stated expiration date on bottle label and stored refrigerated at what degree celsius

A

2 to 8 degrees celsius

80
Q

If the reagents came from the refrigerated temperature we must

A

Cool down first

81
Q

The rf latest reagents one shaken must be uniform without

A

Visible clumping

82
Q

The Rf latex reagent when stored refrigerated there is a presence of______. And it should be considered normal

A

Slight sedimentation

83
Q

Do not use the latex reagent or control if they become

A

Contaminated

84
Q

Using contaminated latex reagent results in

A

Invalid results

85
Q

We should interpret the result strictly in 2 minutes because it is sensitive to

A

False positive results

86
Q

Rf is not specific

A

True

87
Q

Specific for RA

A

Anti-CCP

88
Q

It is simply an autoimmune disease compared with _____ which is a consequence of streptococcus infection

A

Rheumatoid arthritis
Acute RHEUMATIC FEVER

89
Q

Passive agglutination reaction has a carrier particle which is

A

Latex particle

90
Q

Crp and aso carries antigens
RF carries___

A

Antibodies (IgG)

91
Q

Rf detects ___

A

Antibody

Imse Lab (2 decks)

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