Q: Which equation correctly calculates the basic reproductive number ($$R_0) $$for an infectious disease, given the transmission rate ($$\beta$$), recovery rate ($$\gamma$$), and population size ($$N$$)?

$$R_0$$ = \frac{\beta \times N}{\gamma}$$

Q: If a disease has an $$R_0 of 4$$, what percentage of the population must be immune to achieve herd immunity?

$$\left(1 - \frac{1}{R_0$}\right) \times 100\% = 75\%$$

Question 1

Which of the following best describes the function of opsonins in the immune response?

Accepted Answer

Opsonins coat pathogens, enhancing their recognition and uptake by phagocytes.

Question 2

A patient presents with a parasitic infection. Which leukocyte would you expect to be elevated in their blood count?

Accepted Answer

Eosinophils

Question 3

Which of the following statements about the complement system is TRUE?

Accepted Answer

Complement proteins are activated in a cascading sequence, leading to opsonization, inflammation, and cytolysis.

Question 4

A laboratory technician is using a direct ELISA to detect the presence of a viral antigen in a patient’s serum. Which of the following best describes the principle behind this assay?

Accepted Answer

The assay uses a primary antibody to capture the antigen and a secondary enzyme-conjugated antibody to produce a measurable signal.

Question 5

Which equation correctly calculates the basic reproductive number ($$R_0) $$for an infectious disease, given the transmission rate ($$\beta$$), recovery rate ($$\gamma$$), and population size ($$N$$)?

Accepted Answer

$$R_0$$ = \frac{\beta 	imes N}{\gamma}$$

Question 6

If a disease has an $$R_0 of 4$$, what percentage of the population must be immune to achieve herd immunity?

Accepted Answer

$$\left(1 - \frac{1}{R_0$}ight) 	imes 100\% = 75\%$$

Question 7

Which of the following is an example of artificial passive immunity?

Accepted Answer

Receiving antivenom after a snake bite

Question 8

A patient receives a live attenuated vaccine. Which of the following statements is TRUE regarding this type of vaccine?

Accepted Answer

It contains weakened pathogens that can replicate and stimulate a strong immune response.

Question 9

Which diagnostic technique is most appropriate for rapidly detecting SARS-CoV-2 antigens in a nasal swab specimen?

Accepted Answer

Lateral flow rapid antigen test

Question 10

Which of the following best explains why monoclonal antibodies are preferred over polyclonal antibodies in certain diagnostic assays?

Accepted Answer

Monoclonal antibodies bind to a single epitope, reducing cross-reactivity and increasing specificity.

Question 11

A patient with systemic lupus erythematosus (SLE) is tested using an indirect immunofluorescence assay. What is being detected in this assay?

Accepted Answer

Antigen-specific antibodies in patient serum using a fluorescent secondary antibody

Question 12

Which of the following best describes the role of MHC II molecules in the immune response?

Accepted Answer

MHC II molecules are expressed only on antigen-presenting cells and present processed antigens to helper T cells.

Question 13

Which of the following is a key difference between PCR and RT-PCR in clinical diagnostics?

Accepted Answer

PCR amplifies DNA, while RT-PCR amplifies RNA by first converting it to DNA.

Question 14

A blood transfusion is planned. Which assay is used to ensure compatibility between donor and recipient blood?

Accepted Answer

Direct hemagglutination assay

Question 15

Which of the following is a cardinal sign of acute inflammation?

Accepted Answer

Erythema

Question 16

A patient is diagnosed with hemolytic disease of the newborn. Which type of hypersensitivity is involved?

Accepted Answer

Type II hypersensitivity

Question 17

Which of the following best describes the mechanism of action for cytotoxic T cells?

Accepted Answer

They recognize antigens presented on MHC I and induce apoptosis in infected cells using perforin and granzymes.

Question 18

Which diagnostic technique uses fluorescent-labeled antibodies to detect specific antigens in a tissue sample?

Accepted Answer

Direct immunofluorescence assay

Question 19

A patient with a suspected viral infection is tested using RT-PCR. Which specimen type is most appropriate for detecting respiratory viruses like SARS-CoV-2?

Accepted Answer

Throat swab

Unit 3 Study Guide: Innate and Adaptive Immunity, Immune System Disorders, and Laboratory Diagnostics

Study Guide - Practice Questions

Study Guide - Flashcards