Serological Tests in Immunology

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What is the type of test called when the lab provides the antigen and looks for the presence of antibodies in the patient's serum?

Indirect test (correct)

Compliment-Fixation test

Direct test

Neutralization test

Which type of reaction involves antigen that is attached to the main pathogen?

Fluorescent-Antibody technique

Precipitation reaction

ELISA

Agglutination reaction (correct)

What is the result of a positive precipitation reaction?

Patient has no disease

Patient has the disease (correct)

Patient is immune to the disease

Patient has antibodies against the disease

What type of antibodies are involved in precipitation reactions?

IgM or IgG Signup and view all the answers

What is the name of the blood test that looks for patient antibodies against Treponema pallidum?

VDRL Test Signup and view all the answers

What is the characteristic of the precipitation reaction at the equivalence zone?

Formation of a cloudy line Signup and view all the answers

What is the type of serological test that involves the reaction of soluble antigens with antibodies?

Precipitation reaction Signup and view all the answers

What is the result of a negative precipitation reaction?

No immune complex formed Signup and view all the answers

What is the primary application of the Direct Fluorescent-Antibody (FA) test?

To identify GAS from a patient's throat sample Signup and view all the answers

What is the purpose of adding Fluorescent dye-labeled Anti-human antibody in the Indirect Fluorescent-Antibody (FA) test?

To react with any human antibody in serum Signup and view all the answers

Which test is used to diagnose bacterial and viral diseases?

Complement-Fixation (CF) reaction Signup and view all the answers

What is the result of a Positive Complement-Fixation (CF) test?

The binding of complement serum proteins to the Ag-Ab complex Signup and view all the answers

What is the main difference between the Direct and Indirect Fluorescent-Antibody (FA) tests?

The type of antibody detected Signup and view all the answers

What is the purpose of the first stage of the Complement-Fixation (CF) test?

To determine if all complement proteins got used and formed an immune complex Signup and view all the answers

What is the main advantage of the Complement-Fixation (CF) reaction?

It is a highly sensitive test Signup and view all the answers

Which statement is true about the Neutralization test?

It is an indirect test Signup and view all the answers

What is the purpose of Lancefield Classification in Streptococcal species?

To distinguish between different species of Streptococcus Signup and view all the answers

What type of antibodies are involved in agglutination reactions?

IgM Signup and view all the answers

What is the result of agglutination reaction?

Clumping of the pathogen in one location Signup and view all the answers

What is the purpose of adding latex beads coated with antibodies in indirect agglutination test?

To detect the presence of antigens in the patient's serum Signup and view all the answers

What is the application of agglutination reaction in blood typing?

To determine the blood group Signup and view all the answers

What happens when anti-B antibody binds to RBC?

It leads to the destruction of RBC Signup and view all the answers

What is the difference between direct and indirect agglutination test?

Direct agglutination test uses latex beads coated with antigens, while indirect agglutination test uses latex beads coated with antibodies Signup and view all the answers

What is the role of immune complexes in agglutination reaction?

They lead to the formation of clumps Signup and view all the answers

Why did compliment not bind in the first step of the complement fixation test?

Because the patient's serum sample did not contain Abs against the antigen Signup and view all the answers

What happens to the compliment in the Compliment Fixation Stage of the test?

It does not get activated and does not bind to the Ab stem region Signup and view all the answers

What is the purpose of introducing sheep RBCs into the patient's serum sample?

To detect the presence of Abs against sheep RBC Signup and view all the answers

What happens to the sheep RBCs in a negative Complement Fixation Test?

They undergo hemolysis Signup and view all the answers

What is the result of a positive Complement Fixation Test?

Hemolysis of sheep RBCs Signup and view all the answers

Why is the compliment available to bind to future immune complex formations in a negative test?

Because it did not bind to the Ab stem region of the immune complex Signup and view all the answers

What is the role of the Abs against sheep RBC in the Indicator Stage of the test?

To form an immune complex with sheep RBC Signup and view all the answers

What is the purpose of the Compliment Fixation Stage of the test?

To determine if the patient has Abs against the antigen Signup and view all the answers

What is the primary advantage of the ELISA method?

It has high specificity and sensitivity Signup and view all the answers

In a Direct ELISA test, what is the role of the enzyme-linked antibody?

It binds to the antigen provided by the patient Signup and view all the answers

In an Indirect ELISA test, what is the role of the enzyme-linked anti-human antibody?

It binds to the antibody provided by the patient Signup and view all the answers

What is the application of ELISA in HIV testing before seroconversion?

It detects the presence of HIV antigens Signup and view all the answers

What is the component of the ELISA test that is provided by the patient in a Direct ELISA test?

Pathogen Signup and view all the answers

What is the characteristic of the ELISA method that makes it suitable for home pregnancy testing?

It is a highly specific and sensitive test Signup and view all the answers

What is the advantage of using monoclonal antibodies in a home pregnancy test?

They are more specific to hCG than polyclonal antibodies Signup and view all the answers

What is the relative sensitivity of the ELISA method compared to other serological tests?

It is more sensitive than other tests Signup and view all the answers