Diagnostic Testing

Questions and Answers

Which component of the immune response is predominantly detected by measuring IgM antibodies in a patient’s serum?

Chronic infection

Recent infection (correct)

Past immunity

Autoimmune disorders

What is the main purpose of using monoclonal antibodies in diagnostic immunology?

To induce a stronger immune reaction

To detect multiple types of antigens concurrently

To measure the overall immune response

To obtain a high purity of a single type of antibody (correct)

In the enzyme immunoassay (EIA), what is primarily coated on the plastic wells?

Fluorescent markers

Proteins (antigens) (correct)

Patient serum

Enzymes

Which test is primarily used for diagnosing latent tuberculosis infections?

Mantoux test Signup and view all the answers

What indicates a significant increase in IgG antibody levels for determining recent infection?

A four-fold increase Signup and view all the answers

Which method is effective for rapid on-site detection of infectious diseases through direct observation?

Fluorescent microscopy Signup and view all the answers

What is the key principle behind particle agglutination tests in diagnostic immunology?

Formation of immune complexes Signup and view all the answers

What is the primary application of fluorescent microscopy mentioned?

To detect cellular infections such as influenza Signup and view all the answers

During the EIA test for detecting streptococcal antigens, what is the role of the enzyme-tagged antibody?

To sandwich the antigen for visualization Signup and view all the answers

Which procedure is specifically categorized as a 'Point of Care' test?

EIA test for Gp A Strep Signup and view all the answers

What process occurs after the urine specimen is placed in the mini ELISA kit?

It diffuses along the filter and binds to the HCG antigen if present Signup and view all the answers

Which virus can be detected using fluorescent microscopy according to the information provided?

Herpes virus Signup and view all the answers

What is the significance of washing off unattached antibodies in the process described?

To ensure only specific binding is observed Signup and view all the answers

Which step follows the enzyme substrate addition in the EIA test?

Observe for a color change indicating a positive result Signup and view all the answers

How does fluorescent microscopy display positive identification of infected cells?

By emitting light when cells are bound with antibodies Signup and view all the answers

Which testing method specifically involves scraping cells from lesions?

Fluorescent microscopy Signup and view all the answers

What is indicated by a positive C line on an HIV saliva antibody test?

The test worked and is ready to be interpreted. Signup and view all the answers

In a particle agglutination test for detecting antigens, what observation indicates the presence of the right antigen?

The particles agglutinate, making the suspension granular. Signup and view all the answers

What is the primary purpose of adding the second antibody in the EIA process?

To tag the patient’s antibody for detection Signup and view all the answers

Which of the following is a key feature of the Mantoux test for diagnosing tuberculosis?

Antigens are injected into the skin and local swelling is measured. Signup and view all the answers

Which step in the EIA process allows for the measurement of antibodies in a patient's sample?

Adding the substrate for the enzyme Signup and view all the answers

What can be achieved by using particle agglutination methods coated with antibodies?

Identification of specific antibodies in patient serum. Signup and view all the answers

In fluorescence microscopy, what is the primary function of labeling antibodies with a fluorescent tag?

To visualize the presence of the target antigen Signup and view all the answers

Which of the following best describes the process of adding the patient's serum to a well in an EIA?

It allows antigens to bind specifically to antibodies coated in the well. Signup and view all the answers

How does the TB skin test determine the presence of TB infection?

By observing the immune response at the injection site. Signup and view all the answers

What type of specimen can particle agglutination testing analyze?

Cerebrospinal fluid or cultured bacteria. Signup and view all the answers

What is a common disadvantage of particle agglutination methods compared to EIA?

It is less specific to the antigen being tested. Signup and view all the answers

Which statement is true regarding the incubation step in the fluorescence microscopy process?

It allows the fluorescently tagged antibody to bind to the target antigen. Signup and view all the answers

Which statement is true regarding the agglutination process in particle agglutination tests?

Agglutination is caused by antibodies binding to antigens. Signup and view all the answers

In the context of skin testing for infectious diseases, what role does the antigen play?

It allows the immune system to recognize the pathogen. Signup and view all the answers

Study Notes

Immune Response Detection Methods

Specific antibodies in patient's serum bind to corresponding antigens.
Non-bound antibodies are washed away, leaving only those attached to the antigen.
Addition of a second antibody, tagged with an enzyme, sticks to the patient's antibody.
The enzyme-linked antibody is usually derived from animals targeting human antibodies.

Enzyme Immunoassays (EIAs)

If the patient's antibodies are present, the enzyme remains bound after washing.
Adding a substrate triggers a color change, indicating the presence and amount of antibody.
Examples include tests for measles, HIV, and Hepatitis A, B, or C.

Antigen Detection in Serum

Wells are coated with specific antibodies; patient serum is added for binding with antigens.
Non-binding antigens are washed away, followed by the addition of an enzyme-tagged second antibody.
Color change occurs with enzyme substrate, indicating the presence of the antigen (e.g., Hepatitis B Surface Antigen, HBsAg).

Fluorescence Microscopy

Specimens are prepared on slides, dried, and fixed to prevent loss during washing.
Antibodies labeled with fluorescent tags are applied; they bind only if the target antigen is present.
Used for detecting infections in tissue samples.

Types of Antibodies

Polyclonal antibodies are produced by immunizing animals, generating a variety of antibodies against one protein.
Monoclonal antibodies are produced from a mix of spleen cells and cancerous myeloma cells, resulting in a highly pure antibody specific to one antigen.

Antibody Measurement in Serum

IgM antibody presence indicates recent infections like measles or Hepatitis A.
Rising IgG levels can suggest a recent infection, typically a four-fold increase.
High antibody titers can signal infections, such as Q fever.
IgG presence can indicate immunity (e.g., Rubella, Hepatitis A).

Particle Agglutination Tests

Patient specimens are mixed with antibody-coated beads or particles (often latex); a milky appearance indicates no reaction.
If the antigen is present, agglutination occurs, changing the suspension from milky to granular.
Useful for identifying bacteria and testing spinal fluid, even under antibiotic treatment.

Skin Testing

The Mantoux test gauges cellular immune response to TB antigens injected into the skin.
Induration and swelling indicate recognition of TB antigens; size is measured for diagnostics.

Fluorescent Microscopy Applications

Employed to detect viral infections such as influenza, RSV, herpes, and varicella zoster virus from clinical samples.
Can also identify Pneumocystis in respiratory samples.

Point-of-Care Testing

Mini EIA kits allow for rapid antigen detection, such as Group A Streptococcus from throat swabs.
Pregnancy tests use urine specimens; a color change indicates the presence of human chorionic gonadotropin (HCG) when bound to the antibody in the device.

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Description

This quiz focuses on the techniques involved in antibody testing, specifically the binding and detection of antibodies in serum. It covers the steps of washing wells, distinguishing specific antibodies, and the use of tagged antibodies for detection. Perfect for students studying immunology and laboratory methods.