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

Week 8: Rheumatoid Factor Latex Agglutination Test Flashcards

(91 cards)

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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
Sample serum
100 ul
26
What tube does have sample serum only
Tube 1
27
How many ul of saline is used in tubes 1 to 5
100 ul
28
What is the sample volume of tube 1 to 5
50 ul
29
Titer of tube 1 to 5
16, 32, 64, 128, 256 8×Df= IU/ml
30
Reciprocal of the highest dilution showing macroscopic of glutination
Titer
31
If agglutination occurs in dilution 3 the titer is
64
32
Dilution factor is eight because this is the sensitivity of
Rf latex agglutination test
33
IU/ml of specimen =
IU/ml control specimen titer
34
The approximately rf level present in the sample may be obtained by
Multiplying the titer by the analytical sensitivity of rf latest reagent which is 8 IU/ml
35
Rheumatoid arthritis is another example of a
Systemic autoimmune disorder
36
How many percent does rheumatoid arthritis affects the adult population
0.5% to 1.0%
37
Prevalence of rheumatoid arthritis varies with
Ethnicity and geographic location
38
Women are ___ as likely to be affected as men
3 times
39
The prevalence of the disease is highest in women who are
More than 65 years of age
40
Rheumatoid arthritis can be characterized as
Chronic, symmetric, and erosive arthritis of the peripheral joints It can also affect multiple organs such as **heart and the lungs**
41
Association of RA with more than ____ genetic regions have been discovered
30
42
The strongest associations have been between a subset of patients with ra and specific ____ and ____.
HLA-DRB1 alleles or PTPN22 gene polymorphisms
43
The strongest environmental risk factor for ra is believed to be
Cigarette smoking which doubles the risk of developing the disease
44
The pathology of ra is caused by an inflammatory process that results in the
Destruction of bone and cartilage
45
The ______ in rheumatoid joints show an increase in cell lining the synovial membrane and formation of a panus
Lesions
46
Organized mass cell/ a sheet of inflammatory granulation tissue that grows into the joint space and invades the cartilage
Pannus
47
Evidence of immunologic activity within the joint is the infiltration of the inflamed synovium with? (Cells)
T and B lymphocytes Plasma cells Dendritic cells Mast cells Granulocytes
48
What is the role of autoantibodies in the initiation of the inflammatory response
Not known
49
Two key antibodies found in the disease are:
Rheumatoid factor Anti–cyclic citrullinated peptide (anti-CCP)
50
Rheumatoid factor is an antibody that is most often of the igM class and is directed against which portion of igG
FC Portion
51
It has been postulated that rheumatoid factors may play a role in the pathogenesis of rheumatoid arthritis by increasing ___ and ___.
Macrophage activity and enhancing antigen presentation to T cells by apcs (antigenpresenting cells)
52
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
Type 3 hypersensitivity reaction or immune complex
53
What complement protein binds to the immune complexes, activating the classical component cascade?
C1
54
During this process ___and ___ are generated, which act as chemotactic factors for neutrophils and macrophages
C3a and c5a
55
It acts as a chemotactic factor for neutrophils and macrophages
C3a and c5a
56
The continual presence of this cells (neutrophils and macrophages) and their associated cytokines leads to
Chronic inflammation which damages the synovium itself
57
Diagnosis of rheumatoid arthritis is based on a combination of
Clinical manifestations Radiographic findings and Laboratory testing
58
It is the antibody that is most often tested to aid in making the initial diagnosis
Rf or rheumatoid factor
59
The importance of testing for the presence of rf is also reflected in the fact that it is one of the classification criteria for
Rheumatoid arthritis
60
It is an auto antibody that is usually in the igm class that reacts with the fc portion of igg
Rheumatoid factor
61
Approximately _____of patients with rheumatoid arthritis test positive for rf
70% to 90% of patients
62
A negative test or result does not rule out the presence of ra
True
63
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
5% of healthy individuals 10% to 25% of those over the age of 65
64
Rf is present in about ___ in healthy individuals
5%
65
Rf can be found in patients with other connective tissue diseases such as
Systemic lupus erythematosus Sjogren's syndrome Scleroderma Mixed connective tissue disease People with some chronic infections
66
Manual agglutination test using __ or ___ have been used for many years to detect rf
Charcoal or latex particles coated with igG
67
These test, however only detect the igM isotype found in about 75% of the patients
Manual agglutination tests
68
Manual agglutination test only detect the
IgM isotype
69
Igm isotype is found in about how many percent of patients
75%
70
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:
Enzyme link immunosorbent assay chemiluminescence immunoassay Nephelometric methods
71
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:
Measurement of erythrocyte sedimentation rate C-reactive protein Complement components
72
What is the typical result of esr and crp
Elevated
73
Resutls of the levels of serum complement components are
Normal or increased because of increased acute phase reactivity
74
Levels of serum component complements are normal or increase because of increase
Acute-phase reactivity
75
The result should be read in____ mixing the reagent on the slide
2 minutes after
76
Existence of __ at high titers has not been encountered
Prozone
77
Increased levels of rheumatoid factor may be around in some diseases other than rheumatoid arthritis such as
Mononucleosis or sarcoidosis Lupus Erythematosus Sjogren's syndrome
78
Certain patients with rheumatoid arthritis will not have the rf present in their serum
True
79
Reagents are stable until stated expiration date on bottle label and stored refrigerated at what degree celsius
2 to 8 degrees celsius
80
If the reagents came from the refrigerated temperature we must
Cool down first
81
The rf latest reagents one shaken must be uniform without
Visible clumping
82
The Rf latex reagent when stored refrigerated there is a presence of______. And it should be considered normal
Slight sedimentation
83
Do not use the latex reagent or control if they become
Contaminated
84
Using contaminated latex reagent results in
Invalid results
85
We should interpret the result strictly in 2 minutes because it is sensitive to
False positive results
86
Rf is not specific
True
87
Specific for RA
Anti-CCP
88
It is simply an autoimmune disease compared with _____ which is a consequence of streptococcus infection
Rheumatoid arthritis Acute RHEUMATIC FEVER
89
Passive agglutination reaction has a carrier particle which is
Latex particle
90
Crp and aso carries antigens RF carries___
Antibodies (IgG)
91
Rf detects ___
Antibody

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