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Questions and Answers
What is the principle underlying immunodiagnosis of disease?
What is the principle underlying immunodiagnosis of disease?
In which application is antigen detection commonly used?
In which application is antigen detection commonly used?
What does serology testing involve the detection of?
What does serology testing involve the detection of?
Which component of serology testing involves specimen collection and transport?
Which component of serology testing involves specimen collection and transport?
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What is an example of a post-analytical potential error in serology testing?
What is an example of a post-analytical potential error in serology testing?
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For which organisms is serology testing especially useful when they are difficult to isolate through culture?
For which organisms is serology testing especially useful when they are difficult to isolate through culture?
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What is the significance of positive IgM without IgG in a serological test?
What is the significance of positive IgM without IgG in a serological test?
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What does a four-fold rise in antibody titer between the acute and convalescent phases indicate?
What does a four-fold rise in antibody titer between the acute and convalescent phases indicate?
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In serology testing, what is the significance of the zone of equivalence?
In serology testing, what is the significance of the zone of equivalence?
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What is a common cause of false negative results in serology testing?
What is a common cause of false negative results in serology testing?
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What does a compound dilution of 1:500 indicate in serology testing?
What does a compound dilution of 1:500 indicate in serology testing?
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What does the presence of IgG without IgM in a serological test indicate?
What does the presence of IgG without IgM in a serological test indicate?
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What does a rapid increase to a higher level of IgG after a secondary antibody response indicate?
What does a rapid increase to a higher level of IgG after a secondary antibody response indicate?
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What does a high level of IgM without IgG in a serological test indicate?
What does a high level of IgM without IgG in a serological test indicate?
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What is the significance of positive IgG without IgM in a serological test?
What is the significance of positive IgG without IgM in a serological test?
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What does a gradual decline of IgG to undetectable levels over several months indicate?
What does a gradual decline of IgG to undetectable levels over several months indicate?
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What does a high level of IgG without IgM in a serological test indicate?
What does a high level of IgG without IgM in a serological test indicate?
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Study Notes
Principles of Immunodiagnosis
- Immunodiagnosis is based on the interaction between antigens and antibodies to diagnose diseases.
- It assesses the presence of specific antibodies or antigens related to infectious agents or conditions.
Applications of Antigen Detection
- Commonly used for diagnosing infections by identifying the presence of pathogens directly in specimens.
- Useful in rapid testing scenarios, such as detecting viral infections like influenza or COVID-19.
Serology Testing
- Involves detecting antibodies in serum to assess immune response against pathogens.
- Typically used for diagnosing infections, autoimmune diseases, and blood grouping.
Specimen Collection and Transport
- The serology testing component responsible for specimen collection and transport is the pre-analytical phase.
- Proper handling and transportation of samples are crucial for accurate results.
Post-Analytical Potential Errors
- An example includes misinterpretation of assay results due to incorrect data reporting or documentation errors.
- Monitoring system failures or technician errors can also lead to false conclusions.
Usefulness of Serology Testing
- Particularly beneficial for organisms that are difficult to isolate via culture, such as certain viruses, spirochetes, and intracellular bacteria.
- Provides an alternative diagnostic method when traditional cultures are infeasible.
Significance of Positive IgM Without IgG
- Indicates a recent infection; IgM is the first antibody produced in response to an infection.
- Suggests acute phase of illness and a lack of past exposure or immunity to the pathogen.
Four-Fold Rise in Antibody Titer
- Indicates a significant increase in the immune response, suggesting active infection or recent exposure.
- Used as a diagnostic criterion in many infectious diseases.
Significance of the Zone of Equivalence
- The zone where antibody-antigen complexes form optimally, leading to visible precipitation in serological tests.
- Affects the sensitivity and specificity of the tests performed.
Common Causes of False Negative Results
- Occurs due to timing of specimen collection relative to infection (window period).
- Can also result from improper sample handling or storage temperature.
Compound Dilution in Serology Testing
- A compound dilution of 1:500 indicates the sample has been diluted up to 500 times from its original concentration.
- Used to quantify antibody levels in the patient’s serum.
Presence of IgG Without IgM in Serological Tests
- Indicates past infection or exposure; suggests previous immunity to the pathogen.
- May also represent an individual who has been vaccinated.
Secondary Antibody Response
- A rapid increase in IgG levels signifies a strong and quick immune response upon re-exposure to previously encountered pathogens.
- Indicates immunological memory and an effective response.
High Level of IgM Without IgG
- Suggests acute or recent infection; the immune system is actively responding.
- High IgM levels can correlate with the severity or stage of the infection.
Positive IgG Without IgM in Serological Tests
- Confirms previous infections or vaccinations, indicating established immunity.
- Suggests that the person is not currently infected.
Gradual Decline of IgG
- Indicates waning immunity or resolution of the infection.
- Natural progression after successful clearance of a pathogen from the system.
High Level of IgG Without IgM
- Reflects a past infection or vaccination; no current active infection.
- Suggests the body has developed long-term immunity against the pathogen.
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Description
Test your knowledge of immunologic methods and immunodiagnosis of diseases, including the principles of antigen-antibody reactions, direct detection of antigens in clinical specimens, and detection of antibodies in patient serum.
