Basic Immunology And Serology
Clinical Laboratory Technician, Basic Immunology and Serology Exam. Instructional Materials: Clinical Immunology and Serology, A laboratory Perspective, 3rd Ed. 2009 Christine Dorresteyn Steven, McGraw-Hill
Course ID: CL 1110
National American University
Questions and Answers
- 1.
- Acute phase reactants have been determined to be elevated in a patient. What does this result on its own indicate about the patient?
- A.
Inflammation of unknown cause is present.
- B.
Patient has a leukemia but not a lymphoma.
- C.
This is a normal result.
- D.
There is a parasitic infection and not a viral infection.
Correct Answer
A. Inflammation of unknown cause is present.Explanation
Elevated levels of acute phase reactants indicate the presence of inflammation in the patient. However, the cause of the inflammation is unknown. This result suggests that there is an ongoing inflammatory response in the body, but further investigation is needed to determine the underlying cause of the inflammation.Rate this question:
- 2.
- Which is characteristic of natural immunity?
- A.
Memory is involved.
- B.
Lymphocytes play a major role.
- C.
It is very specific.
- D.
It depends on normally present body functions.
Correct Answer
D. It depends on normally present body functions.Explanation
Natural immunity, also known as innate immunity, is a non-specific defense mechanism that is present in the body from birth. It relies on the normal functions of the body, such as the skin and mucous membranes, to provide a barrier against pathogens. This type of immunity does not involve memory or lymphocytes, and it is not specific to a particular pathogen. Instead, it provides a general defense against a wide range of potential threats.Rate this question:
- 3.
What is the major function of C-reactive protein (CRP)?
- A.
Acts as an opsonin
- B.
Binds hemoglobin
- C.
Causes vasodilation
- D.
Helps to form clots
Correct Answer
A. Acts as an opsoninExplanation
C-reactive protein (CRP) acts as an opsonin, which means it enhances the immune system's ability to recognize and eliminate foreign particles, such as bacteria and viruses. By binding to these pathogens, CRP facilitates their recognition and uptake by immune cells, promoting their destruction. This function of CRP is crucial in the body's defense against infections and inflammation.Rate this question:
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- 4.
Which of the following acute phase reactants is an important clotting factor?
- A.
Haptoglobin
- B.
Ceruloplasmin
- C.
Fibrinogen
- D.
Alpha-2 macroglobulin
Correct Answer
C. FibrinogenExplanation
Fibrinogen is an important clotting factor because it plays a crucial role in the formation of blood clots. When there is tissue damage or injury, fibrinogen is converted into fibrin by the enzyme thrombin. Fibrin forms a mesh-like structure that helps in the clotting process by trapping platelets and other blood cells, forming a stable clot. This clot then prevents excessive bleeding and allows for the healing of the damaged tissue.Rate this question:
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- 5.
In 1796, Edward Jenner's discovery that cowpox generated immunity against smallpox is based on the princple of?
- A.
Attenuation of a harmful substance
- B.
Natural immunity
- C.
Passive immunity
- D.
Cross-immunity
Correct Answer
D. Cross-immunityExplanation
Edward Jenner's discovery that cowpox generated immunity against smallpox is based on the principle of cross-immunity. Cross-immunity refers to the phenomenon where immunity to one disease provides protection against another related disease. In this case, Jenner observed that individuals who had been infected with cowpox, a milder disease, were also protected against smallpox, a more severe and deadly disease. This discovery led to the development of the smallpox vaccine and marked a major breakthrough in the field of immunology.Rate this question:
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- 6.
All of the following are characteristics of acute phase reactants EXCEPT:
- A.
Increase rapidly in response to infection
- B.
Used to diagnose a specific disease
- C.
Enhanced phagocytosis
- D.
Promote inflammation
Correct Answer
B. Used to diagnose a specific diseaseExplanation
Acute phase reactants are proteins that are produced by the liver in response to inflammation or infection. They are used as markers to monitor the presence and severity of these conditions, but they are not specific enough to diagnose a specific disease. Therefore, the correct answer is "Used to diagnose a specific disease."Rate this question:
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- 7.
What is the function of the acute phase protein haptoglobin?
- A.
Acts as an opsonin
- B.
Forms clots
- C.
Binds hemoglobin
- D.
Acts as a chemotaxin
Correct Answer
C. Binds hemoglobinExplanation
Haptoglobin is an acute phase protein that binds to free hemoglobin in the blood. When red blood cells are damaged or destroyed, hemoglobin is released into the bloodstream. Haptoglobin binds to this free hemoglobin, preventing its toxic effects and facilitating its removal by macrophages. This helps to prevent oxidative damage and kidney injury that can occur due to the presence of free hemoglobin. Therefore, the function of haptoglobin is to bind hemoglobin.Rate this question:
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- 8.
Measurement of CRP levels could be useful for which of the following?
- A.
To determine risk of a heart attack
- B.
To determine flare up of rheumatoid arthritis
- C.
To detect an inflammatory process
- D.
All of the above
Correct Answer
D. All of the aboveExplanation
Measurement of CRP levels could be useful in determining the risk of a heart attack because elevated levels of CRP in the blood indicate inflammation, which is a risk factor for heart disease. It can also be used to determine the flare-up of rheumatoid arthritis, as high CRP levels are associated with increased disease activity. Additionally, CRP levels can be measured to detect an inflammatory process in the body, as it is a marker of inflammation. Therefore, all of the given options are correct and CRP measurement can be useful for all of these purposes.Rate this question:
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- 9.
Acquired immunity can be characterized by which of the following?
- A.
Nonspecific
- B.
Immediate response
- C.
Depends on neutrophils and macrophages
- D.
Involves memory
Correct Answer
D. Involves memoryExplanation
Acquired immunity is characterized by the involvement of memory. This means that the immune system has the ability to recognize and remember specific pathogens that it has encountered before. When the body is exposed to a particular pathogen for the first time, the immune system mounts a response to eliminate it. However, during this initial encounter, the immune system also creates memory cells that "remember" the pathogen. If the body is exposed to the same pathogen again in the future, the immune system can mount a faster and more effective response due to the presence of these memory cells.Rate this question:
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- 10.
Which of the following best explains the reaction that takes place in the latex agglutination slide test for CRP?
- A.
Latex particles are coated with anti-CRP
- B.
Latex particles are coated with CRP
- C.
Latex particles are nonspecifically bound
- D.
CRP is acting as an antibody
Correct Answer
A. Latex particles are coated with anti-CRPExplanation
In the latex agglutination slide test for CRP (C-reactive protein), latex particles are coated with anti-CRP antibodies. When a sample containing CRP is added to the latex particles, the CRP molecules bind to the anti-CRP antibodies on the latex particles, causing agglutination or clumping of the latex particles. This reaction is specific to CRP and indicates the presence of CRP in the sample.Rate this question:
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- 11.
The ability to resist infection through normally present body functions best characterizes:
- A.
Autoimmunity
- B.
Natural immunity
- C.
Acquired immunity
- D.
Alloimmunity
Correct Answer
B. Natural immunityExplanation
Natural immunity refers to the ability of the body to resist infection through its normal physiological processes, such as the skin acting as a physical barrier, mucous membranes producing mucus to trap pathogens, and the immune system's innate response to destroy and eliminate pathogens. This type of immunity is present from birth and provides a general defense against a wide range of pathogens. Autoimmunity, acquired immunity, and alloimmunity are different types of immune responses that are not specifically related to the body's normal functions in resisting infection.Rate this question:
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- 12.
Antigen-independent differentiation of B cells occurs in the:
- A.
Bone marrow
- B.
Spleen
- C.
Lymph node
- D.
Peyer's patches
Correct Answer
A. Bone marrowExplanation
B cells undergo antigen-independent differentiation in the bone marrow. This is where B cells develop from hematopoietic stem cells and undergo a series of maturation processes, including rearrangement of immunoglobulin genes and expression of surface immunoglobulin receptors. Antigen-independent differentiation in the bone marrow is crucial for the generation of a diverse repertoire of B cells with different antigen specificities. Once mature, B cells leave the bone marrow and migrate to secondary lymphoid organs such as the spleen, lymph nodes, and Peyer's patches, where they can encounter antigens and undergo further activation and differentiation.Rate this question:
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- 13.
When IgM on the surface of an immature B cell binds to a self-antigen, which of the following processes can occur?
- A.
Class switch
- B.
Affinity maturation
- C.
Apoptosis
- D.
Differentiation
Correct Answer
C. ApoptosisExplanation
When IgM on the surface of an immature B cell binds to a self-antigen, the process of apoptosis can occur. Apoptosis is a programmed cell death mechanism that eliminates cells that are potentially harmful or dysfunctional. In this case, when the immature B cell recognizes a self-antigen, it is considered as potentially harmful to the body. To prevent any autoimmune reactions, the B cell undergoes apoptosis, ensuring the removal of the self-reactive cell.Rate this question:
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- 14.
The receptor for antigen on a mature B cell and first immunoglobulin to appear in immune response is:
- A.
MHC class I
- B.
IgG
- C.
IgM
- D.
MHC class II
Correct Answer
C. IgMExplanation
IgM is the first immunoglobulin to appear in the immune response and is the receptor for antigens on a mature B cell. It plays a crucial role in the primary immune response by binding to antigens and initiating the activation of B cells. IgM is a pentameric antibody that is primarily found in the bloodstream and lymph fluid, and it is particularly effective at neutralizing pathogens and activating complement.Rate this question:
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- 15.
T lymphocytes undergo antigen-independent maturation in the:
- A.
Thymus
- B.
Bone marrow
- C.
Lymph node
- D.
Spleen
Correct Answer
A. ThymusExplanation
T lymphocytes undergo antigen-independent maturation in the thymus. The thymus is a specialized organ of the immune system located in the upper chest. It is responsible for the development and maturation of T lymphocytes, also known as T cells. T cells are a type of white blood cell that play a crucial role in the immune response. In the thymus, T cells undergo a process called positive and negative selection, where they learn to recognize self from non-self antigens. This maturation process is essential for the proper functioning of the immune system.Rate this question:
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- 16.
An immature T cell differs from a mature T cell because an immature T cell:
- A.
Expresses beta chains and pre Ta
- B.
Does not express T-cell receptor or CD3
- C.
Co-expresses CD4 and CD8
- D.
Is normally found in lymph nodes
Correct Answer
C. Co-expresses CD4 and CD8Explanation
An immature T cell co-expresses CD4 and CD8, which means it has both CD4 and CD8 proteins on its surface. This is different from a mature T cell, which only expresses either CD4 or CD8. The co-expression of CD4 and CD8 on an immature T cell is important for its development and selection in the thymus. Once the T cell matures, it will undergo a process called positive selection, where it will only express either CD4 or CD8, depending on its function as a helper or cytotoxic T cell.Rate this question:
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- 17.
In antiboy-dependent cell-mediated cytotoxicity, target cells are recognized by which of the following?
- A.
T-cell receptor on the effector cell binding to Fab of IgG bound to the target cell
- B.
C-type lectin inhibitory receptors on effector cell binding to class I on target cell
- C.
CD16 on the effector cell binding to Fc of IgG to the target cell
- D.
CD154 on the effector cell binding to CD40 on the target cell
Correct Answer
C. CD16 on the effector cell binding to Fc of IgG to the target cellExplanation
In antiboy-dependent cell-mediated cytotoxicity, the effector cell recognizes the target cell through CD16 binding to the Fc region of IgG on the target cell. This interaction triggers the cytotoxic response, leading to the destruction of the target cell. CD16 is a receptor found on the surface of natural killer cells and macrophages, and it plays a crucial role in mediating antibody-dependent cell-mediated cytotoxicity. By binding to the Fc region of IgG antibodies that are bound to the target cell, CD16 helps to initiate the destruction of the target cell.Rate this question:
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- 18.
Which of the following best descibes HLA class II molecules?
- A.
They interact with CD8 and T cells
- B.
They have an alpha chain and beta-2 microglobulin
- C.
They have alpha and beta chains of equal size
- D.
They combine with antigen made inside the cell
Correct Answer
C. They have alpha and beta chains of equal sizeExplanation
HLA class II molecules are proteins found on the surface of certain immune cells, including antigen-presenting cells. They play a crucial role in the immune response by presenting antigens to CD4+ T cells. These molecules are composed of two chains, an alpha chain and a beta chain, which are of equal size. This structural characteristic allows them to bind and present antigens that are derived from extracellular sources, such as pathogens or proteins taken up by the cell. Therefore, the statement "They have alpha and beta chains of equal size" accurately describes HLA class II molecules.Rate this question:
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- 19.
Which of the following is true of HLA (MHC) class I antigens?
- A.
They are recognized by helper T cells.
- B.
They are found on all nucleated cells
- C.
They combine with exogenous antigen
- D.
They are coded for on chromosome 9
Correct Answer
B. They are found on all nucleated cellsExplanation
HLA (MHC) class I antigens are found on all nucleated cells. This means that these antigens are present on the surface of almost all cells in the body except for red blood cells. They play a crucial role in the immune system by presenting antigens to cytotoxic T cells, which then initiate an immune response against infected or abnormal cells. This widespread distribution of HLA class I antigens allows for efficient detection and elimination of potentially harmful cells throughout the body.Rate this question:
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- 20.
Heterophile antigens are characterized as:
- A.
Found in unrelated plants or animals but cross-react with the same antibody
- B.
One's own self-antigens
- C.
Any antigen used for immunization
- D.
All of the above
Correct Answer
A. Found in unrelated plants or animals but cross-react with the same antibodyExplanation
Heterophile antigens are characterized as found in unrelated plants or animals but cross-react with the same antibody. This means that these antigens can be present in different species but can still trigger an immune response in the same way, as they are recognized by the same antibodies. This cross-reactivity allows for the development of diagnostic tests, such as the monospot test for infectious mononucleosis, where antibodies produced against one heterophile antigen can also react with a similar antigen from another species.Rate this question:
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- 21.
HLA (MHC) class I protein is found on:
- A.
RBCs
- B.
All nucleated cells
- C.
B cells and macrophages
- D.
Stem cells only
Correct Answer
B. All nucleated cellsExplanation
HLA (MHC) class I proteins are found on all nucleated cells. This is because these proteins play a crucial role in the immune system by presenting antigens to T cells, which helps in identifying infected or abnormal cells. Since all nucleated cells have the potential to be infected or abnormal, it is necessary for them to express HLA class I proteins to enable immune recognition and response. Therefore, HLA class I proteins are not limited to specific cell types like RBCs, B cells, macrophages, or stem cells, but are present on all nucleated cells.Rate this question:
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- 22.
Which MHC class of antigens is necessary for antigen recognition by CD4-positive T-cells?
- A.
Class I
- B.
Class II
- C.
Class III
- D.
No MHC molecule is necessary for antigen recognition
Correct Answer
B. Class IIExplanation
Class II MHC antigens are necessary for antigen recognition by CD4-positive T-cells. CD4-positive T-cells are a type of immune cell that plays a crucial role in coordinating the immune response. These cells recognize antigens presented by MHC class II molecules on the surface of antigen-presenting cells. MHC class II molecules are primarily expressed on antigen-presenting cells such as dendritic cells, macrophages, and B cells. When a CD4-positive T-cell recognizes an antigen presented by MHC class II, it triggers an immune response to eliminate the antigen. Therefore, Class II MHC antigens are necessary for antigen recognition by CD4-positive T-cells.Rate this question:
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- 23.
All of the following are characteristics of both MHC class I and class II molecules EXCEPT:
- A.
Expressed codominantly
- B.
Involved in antigen recognition
- C.
Members of the immunoglobulin superfamily
- D.
Expressed constitutively on all nucleated cells
Correct Answer
D. Expressed constitutively on all nucleated cellsExplanation
MHC class I and class II molecules are both involved in antigen recognition and are members of the immunoglobulin superfamily. They are also expressed codominantly, meaning that both alleles of the gene are expressed. However, they are not expressed constitutively on all nucleated cells. MHC class I molecules are expressed on most nucleated cells, while MHC class II molecules are primarily expressed on antigen-presenting cells.Rate this question:
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- 24.
Which complement component is found in both the classic and alternative pathways?
- A.
C1
- B.
C2
- C.
Factor B
- D.
C3
Correct Answer
D. C3Explanation
C3 is found in both the classic and alternative pathways of the complement system. It is a crucial component that plays a central role in the activation and amplification of the complement cascade. C3 is cleaved into C3a and C3b, where C3b binds to the surface of pathogens and opsonizes them for phagocytosis. This activation of C3 is a common step in both the classic and alternative pathways, making it the correct answer.Rate this question:
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- 25.
Which of the following can activate the alternative complement pathways?
- A.
IgG
- B.
Mannose-Binding Lectin
- C.
C3b
- D.
C1q
Correct Answer
C. C3bExplanation
C3b can activate the alternative complement pathways. C3b is a component of the complement system that plays a crucial role in the activation of the alternative pathway. When C3b binds to a foreign surface, it recruits other complement proteins and initiates a cascade of reactions that lead to the formation of a membrane attack complex, which can destroy the target cell. Therefore, C3b is an important activator of the alternative complement pathways.Rate this question:
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- 26.
Chemotactic and analyphylatic factors are produced by proteolytic cleavage of:
- A.
C1q, C1r, C1s
- B.
C4, C2
- C.
C5, C3
- D.
C5, C6, C7, C8
Correct Answer
C. C5, C3Explanation
Chemotactic and anaphylactic factors are produced by proteolytic cleavage of C5 and C3. This cleavage process generates smaller fragments of C5 and C3, which are responsible for attracting immune cells to the site of infection or inflammation (chemotactic) and triggering allergic reactions (anaphylactic). These factors play a crucial role in the immune response and help in the recruitment and activation of immune cells to fight against pathogens.Rate this question:
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- 27.
The target recognition molecule of the lectin pathway that initiates complement activation is:
- A.
C1q
- B.
C4
- C.
C5b6789
- D.
Mannose-Binding Lectin
Correct Answer
D. Mannose-Binding LectinExplanation
The target recognition molecule of the lectin pathway that initiates complement activation is Mannose-Binding Lectin. This molecule binds to carbohydrates on the surface of pathogens, such as bacteria or viruses, initiating the activation of the complement system. Once bound, Mannose-Binding Lectin recruits other complement proteins to the pathogen surface, leading to the formation of a membrane attack complex and ultimately the destruction of the pathogen. C1q, C4, and C5b6789 are all components of the classical pathway of complement activation, not the lectin pathway.Rate this question:
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- 28.
Which immunolglobulin(s) help(s) initiate the classic complement pathway?
- A.
IgA and IgD
- B.
IgM only
- C.
IgG and IgM
- D.
IgG only
Correct Answer
C. IgG and IgMExplanation
IgG and IgM are the immunoglobulins that help initiate the classic complement pathway. The classic complement pathway is activated by the binding of IgG or IgM antibodies to antigens on the surface of pathogens. This binding triggers a cascade of reactions that results in the activation of complement proteins and the formation of a membrane attack complex, leading to the destruction of the pathogen. IgA and IgD do not play a direct role in initiating the classic complement pathway.Rate this question:
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- 29.
Which of the following is able to activate complement?
- A.
IgA
- B.
IgD
- C.
IgE
- D.
IgM
Correct Answer
D. IgMExplanation
IgM is able to activate complement. Complement is a group of proteins that play a role in the immune response by promoting inflammation, attracting immune cells, and destroying pathogens. IgM is a type of antibody that is produced during the primary immune response. It can bind to antigens on the surface of pathogens and activate the complement system, leading to the destruction of the pathogen. IgA, IgD, and IgE do not have the ability to activate complement.Rate this question:
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- 30.
On a serial dilution with the following tubes set up, 1:2, 1:4, 1:8, 1:16, 1:32, and 1:64, there is no visible agglutination in the 1:64 tube. What is the titer of the antibody?
- A.
32
- B.
16
- C.
64
- D.
Cannot determine
Correct Answer
A. 32Explanation
The titer of the antibody is 32. This is because the highest dilution that does not show any visible agglutination is in the 1:64 tube. Therefore, the last dilution that showed agglutination is the 1:32 tube, indicating that the titer is 32.Rate this question:
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- 31.
If you want to make 5 mL of a 1:20 dilution, how much serum would be needed?
- A.
0.25 mL
- B.
2 mL
- C.
0.5 mL
- D.
1 mL
Correct Answer
A. 0.25 mLExplanation
To make a 1:20 dilution, the ratio of serum to the final volume should be 1:20. Since the final volume is 5 mL, we can calculate the amount of serum needed by multiplying 5 mL by the ratio (1/20). This gives us 0.25 mL of serum needed to make the dilution.Rate this question:
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- 32.
When a staphylococcal infection is passed between patients due to health-care workers not washing their hands, this represents an example of:
- A.
Lack of chemical hygiene
- B.
A sharps hazard
- C.
The chain of infection
- D.
A specimen transport problem
Correct Answer
C. The chain of infectionExplanation
The chain of infection refers to the process by which infectious diseases are transmitted from one person to another. In this case, the staphylococcal infection is being passed between patients due to health-care workers not washing their hands. This represents a link in the chain of infection, as the infection is being transmitted through direct contact with contaminated hands.Rate this question:
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- 33.
When 0.5 mL of serum is added to 1.5 mL of diluent, what dilution does this represent?
- A.
1:3
- B.
1:4
- C.
1:5
- D.
3:1
Correct Answer
A. 1:3Explanation
When 0.5 mL of serum is added to 1.5 mL of diluent, the total volume becomes 2 mL. The dilution ratio is calculated by dividing the volume of serum (0.5 mL) by the total volume (2 mL). This gives a dilution ratio of 1:4. However, it is important to note that the question asks for the dilution ratio, not the dilution factor. The dilution ratio is the inverse of the dilution factor, so the correct answer is 1:3.Rate this question:
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- 34.
Which of the following best explains the use of universal precautions?
- A.
Handling a urine specimen from a patient with a bacterial infection very carefully
- B.
Wearing gloves in handling a serum specimen from a patient with HIV
- C.
Taking gloves off in the lab to place a serum specimen in a chemistry analyzer
- D.
Treating every specimen in the lab as if it were infectious
Correct Answer
D. Treating every specimen in the lab as if it were infectiousExplanation
Universal precautions refer to a set of infection control practices that are used to prevent the transmission of bloodborne pathogens in healthcare settings. These precautions involve treating every specimen and patient as if they were infectious, regardless of their actual infection status. This approach ensures that healthcare workers take necessary precautions to prevent the spread of infections and protect themselves and others from potential harm. By assuming that all specimens are infectious, healthcare workers can consistently follow appropriate safety measures such as wearing gloves, masks, and other protective equipment, and properly handling and disposing of specimens to minimize the risk of transmission.Rate this question:
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- 35.
An immunlolgic immunoassay situation in which antibody is in excess as compared to antigen is called:
- A.
Postzone
- B.
Prozone
- C.
Equivalence zone
- D.
Zone of equivalence
Correct Answer
B. ProzoneExplanation
In an immunologic immunoassay, the prozone refers to a situation where the antibody is present in excess compared to the antigen. This imbalance can lead to false-negative results as the excessive antibodies can prevent the formation of antigen-antibody complexes necessary for accurate detection.Rate this question:
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- 36.
A serological reaction is set up in which the antigen and antibody are both soluble and form an insoluble complex that is detected macroscopically. What type of assay was described?
- A.
Precipitation
- B.
Agglutination
- C.
Flocculation
- D.
Neutralization
Correct Answer
A. PrecipitationExplanation
In this type of assay, a serological reaction is set up using soluble antigen and antibody. When the antigen and antibody combine, they form an insoluble complex, which can be detected macroscopically. This process is known as precipitation.Rate this question:
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- 37.
The zone at which antibody and antigen are at optimal concentration so that they form a large insoluble lattice together is called the:
- A.
Equivalence zone
- B.
Postzone
- C.
Prozone
- D.
Prezone
Correct Answer
A. Equivalence zoneExplanation
The zone at which antibody and antigen are at optimal concentration so that they form a large insoluble lattice together is called the equivalence zone. In this zone, the antibody and antigen molecules are present in equal amounts, allowing for the formation of a large lattice structure. This lattice formation is important for various immunological reactions, such as precipitation and agglutination. The equivalence zone is crucial for accurate and efficient immune responses.Rate this question:
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- 38.
A situation in which antigen is in excess as compared to antibody is called:
- A.
Prozone
- B.
Postzone
- C.
Equivalence zone
- D.
All of the above
Correct Answer
B. PostzoneExplanation
Postzone refers to a situation in which the antigen is present in excess compared to the antibody. In this scenario, the excess antigen can saturate all the available binding sites on the antibody, preventing the formation of antigen-antibody complexes. This results in a lack of visible reaction or false-negative results in diagnostic tests.Rate this question:
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- 39.
T cells travel from the bone marrow to the thymus for maturation. What is the correct order of the maturation sequence for T cells in the thymus?
- A.
Bone marrow to the cortex, after thymic education, released back to peripheral circulation
- B.
Storage in either the cortex or medulla, release of T cells into the peripheral circulation
- C.
Maturation and selection occur in the cortex, then the medulla, release of mature T cells to secondary lymphoid organs
- D.
Activation and selection occur in the medulla, mature T cells stored in the cortex until activated by antigen
Correct Answer
C. Maturation and selection occur in the cortex, then the medulla, release of mature T cells to secondary lymphoid organsExplanation
T cells undergo maturation and selection in the cortex of the thymus, followed by further maturation and selection in the medulla. Once they have completed this process, mature T cells are released into the secondary lymphoid organs to carry out their immune functions. The correct answer describes the correct sequence of events in the maturation of T cells in the thymus.Rate this question:
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- 40.
Which of the following might adversely affect an electrophoresis reaction?
- A.
Decreasing the strength of the current
- B.
Changing the pH of the buffer
- C.
Increasing the strength of the current
- D.
All of the above
Correct Answer
D. All of the aboveExplanation
All of the options listed can adversely affect an electrophoresis reaction. Decreasing the strength of the current can lead to slower migration of molecules, potentially causing inaccurate results. Changing the pH of the buffer can alter the charge and stability of the molecules being separated, affecting their migration. Increasing the strength of the current can generate excessive heat, leading to denaturation or degradation of the molecules. Therefore, all of these factors can have a negative impact on the electrophoresis reaction.Rate this question:
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- 41.
The Western blot test used to confirm HIV is an example of which of the following?
- A.
Immunofixation
- B.
Immunoelectrophoresis
- C.
Double diffusion
- D.
Passive agglutination
Correct Answer
A. ImmunofixationExplanation
The Western blot test is used to confirm HIV infection by detecting specific antibodies against the virus. Immunofixation is a technique that combines electrophoresis and immunoprecipitation to separate and identify proteins. In the context of HIV confirmation, the Western blot test involves separating viral proteins using electrophoresis and then detecting specific antibodies against these proteins using immunofixation. Therefore, the Western blot test used to confirm HIV is an example of immunofixation.Rate this question:
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- 42.
Electrophoresis followed by diffusion of antibody from wells cut in the gel best describes which of the following?
- A.
Immunofixation electrophoresis
- B.
Immunoelectrophoresis
- C.
Oucherlony diffusion
- D.
Rocket immunodiffusion
Correct Answer
B. ImmunoelectrophoresisExplanation
Immunoelectrophoresis involves the separation of proteins by electrophoresis followed by the diffusion of antibodies from wells cut in the gel. This technique allows for the identification and quantification of specific proteins based on their electrophoretic mobility and reaction with antibodies. It is commonly used in clinical laboratories for the diagnosis and monitoring of various diseases, such as multiple myeloma.Rate this question:
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- 43.
Precipitation reactions involve combination of soluble antibody with:
- A.
Soluble antigen
- B.
Cellular antigens
- C.
Red blood cells
- D.
Radioactive antigen
Correct Answer
A. Soluble antigenExplanation
Precipitation reactions occur when a soluble antibody combines with a soluble antigen. This reaction results in the formation of an insoluble complex called a precipitate. Soluble antigens are substances that can dissolve in a solution, and when they come into contact with soluble antibodies, they form a complex that is no longer soluble and can be observed as a precipitate. Cellular antigens, red blood cells, and radioactive antigens are not mentioned in the question and are therefore not involved in precipitation reactions.Rate this question:
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- 44.
Coombs' reagent is used for what purpose?
- A.
To link small antigens on patient red cells
- B.
To enhance agglutination with IgG coated red blood cells
- C.
To enhance agglutination with IgM coated red blood cells
- D.
To cause a precipitation reaction with small amounts of antibody
Correct Answer
B. To enhance agglutination with IgG coated red blood cellsExplanation
Coombs' reagent is used to enhance agglutination with IgG coated red blood cells. This reagent contains antibodies that specifically bind to IgG antibodies on the surface of red blood cells. When Coombs' reagent is added to a sample containing IgG coated red blood cells, it causes the cells to clump together, or agglutinate. This reaction is useful in various laboratory tests, such as the Coombs' test, which is used to detect and diagnose conditions involving immune-mediated destruction of red blood cells, such as autoimmune hemolytic anemia.Rate this question:
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- 45.
An immunoassay is performed in the following manner to look for an antigen in the patient serum: Patient serum + labeled antigen + known antibody are added together and incubated. Unbound material is washed off. The amount of labeled antigen is then measured. What assay is performed?
- A.
Homeogeneous EIA
- B.
Competitive EIA
- C.
Sandwich EIA
- D.
ELISA
Correct Answer
B. Competitive EIAExplanation
This assay is called Competitive EIA because the patient serum, labeled antigen, and known antibody are added together and incubated. In a competitive assay, the labeled antigen competes with the antigen in the patient serum for binding to the known antibody. The unbound material is washed off, and the amount of labeled antigen that remains bound to the known antibody is measured. The more antigen present in the patient serum, the less labeled antigen will be able to bind to the known antibody, resulting in a lower measured amount of labeled antigen.Rate this question:
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- 46.
An immunoassay was performed in the following way: Antigen is bound to a solid support. Patient serum is added and patient antibodies bind to the antigen. The well is washed and enzyme-labeled anti-immunoglobulin antibodies are added. The well is washed and enzyme substrate is added and enzyme activity is determined. Which immnoassay is described?
- A.
Sandwich
- B.
Competitive
- C.
ELISA
- D.
Homogeneous
Correct Answer
C. ELISAExplanation
The given description of the immunoassay involves the binding of patient antibodies to an antigen on a solid support, followed by the addition of enzyme-labeled anti-immunoglobulin antibodies. This is a characteristic of an ELISA (Enzyme-Linked Immunosorbent Assay), where the enzyme-labeled antibodies are used to detect the presence or quantity of the patient antibodies.Rate this question:
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- 47.
Indirect immunofluorescence is similar to which type of enzyme immunoassay as far as the performance of the assay?
- A.
Competitive
- B.
Sandwich
- C.
ELISA
- D.
Homogeneous
Correct Answer
C. ELISAExplanation
Indirect immunofluorescence is similar to the ELISA (enzyme-linked immunosorbent assay) in terms of the performance of the assay. Both techniques are used to detect and quantify specific antibodies or antigens in a sample. In indirect immunofluorescence, a fluorescent dye is used to label the antibodies, while in ELISA, an enzyme is used to produce a colorimetric signal. Both methods rely on the binding of antibodies to their target molecules, allowing for the detection and measurement of specific immune responses.Rate this question:
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- 48.
A serological reaction is set up in which the antigen is bound to a larger carrier, the antibody is soluble, and they bind and form an insoluble complex that is detected macroscopically. What type of assay is described?
- A.
Precipitation
- B.
Agglutination
- C.
Flocculation
- D.
Neutralization
Correct Answer
B. AgglutinationExplanation
The correct answer is Agglutination. In agglutination assays, the antigen is bound to a larger carrier, such as latex beads or red blood cells, and the antibody is soluble. When the antibody binds to the antigen, it forms visible clumps or aggregates that can be detected macroscopically. This assay is commonly used in blood typing and diagnosing certain infections.Rate this question:
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- 49.
A serological test that uses red blood cells coated with exogenous antigens such as bacterial polysaccharides as a method to detect patient antibodies against that exogenous antigen is called:
- A.
Latex agglutination
- B.
Hemagglutination
- C.
Neutralization
- D.
Complement fixation
Correct Answer
B. HemagglutinationExplanation
Hemagglutination is a serological test that uses red blood cells coated with exogenous antigens to detect patient antibodies against the antigen. In this test, if the patient has antibodies against the antigen, they will cause the red blood cells to clump together or agglutinate. This agglutination can be visually observed, indicating the presence of antibodies. Hemagglutination is commonly used for blood typing and detecting certain viral infections.Rate this question:
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- 50.
If a Coombs' test is positive, which of the following is true?
- A.
Antibody has coated patient red blood cells in vitro
- B.
Antigen is reacting with patient antibody
- C.
Antibody has coated patient red blood cells in vivo
- D.
Antigen has coated patient red blood cells in vivo
Correct Answer
C. Antibody has coated patient red blood cells in vivoExplanation
If a Coombs' test is positive, it means that the patient's red blood cells are being coated with antibodies in vivo. This indicates that the patient's immune system is attacking their own red blood cells, leading to conditions such as autoimmune hemolytic anemia. The Coombs' test detects the presence of these antibodies on the surface of the red blood cells.Rate this question:
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Aug 24, 2023Quiz Edited by
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May 12, 2012Quiz Created by
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