Seroimmunology Practice Exam Questions (Easy to Difficult)
Test your knowledge with our Seroimmunology Practice Exam featuring easy, medium, and hard questions. Each item comes with a clear explanation to help you understand the correct answer and strengthen your exam skills. Perfect for ASCP MLS and MLT exam prep!
🟢 Easy (1–10)
1. Which immunoglobulin is the first to appear in a primary immune response?
A. IgA
B. IgG
C. IgM
D. IgE
Answer: C. IgM
Explanation: IgM is the first antibody produced during a primary immune response, making it a key indicator of recent infection.
2. What is the main function of antibodies?
A. Destroy red blood cells
B. Provide immunity by binding antigens
C. Increase blood pressure
D. Produce white blood cells
Answer: B. Provide immunity by binding antigens
Explanation: Antibodies specifically bind to antigens to neutralize them or mark them for destruction by other immune cells.
3. Which type of hypersensitivity reaction involves IgE antibodies?
A. Type I
B. Type II
C. Type III
D. Type IV
Answer: A. Type I
Explanation: Type I hypersensitivity (e.g., allergies) is mediated by IgE and involves mast cell degranulation.
4. What cell type is primarily responsible for antibody production?
A. T cells
B. Platelets
C. B cells
D. Neutrophils
Answer: C. B cells
Explanation: B cells differentiate into plasma cells, which produce antibodies.
5. The complement system is activated in which immune response?
A. Cellular only
B. Humoral only
C. Both innate and adaptive
D. Only passive immunity
Answer: C. Both innate and adaptive
Explanation: Complement plays a role in both innate immunity (nonspecific) and adaptive (antibody-mediated) responses.
6. What is the function of the Fc region of an antibody?
A. Antigen binding
B. Neutralization
C. Complement activation
D. Disulfide bonding
Answer: C. Complement activation
Explanation: The Fc region interacts with complement and immune cells to mediate effector functions.
7. Which of the following is a secondary lymphoid organ?
A. Thymus
B. Bone marrow
C. Spleen
D. Liver
Answer: C. Spleen
Explanation: The spleen filters blood and is a site where immune responses are initiated, making it a secondary lymphoid organ.
8. What does a positive ANA test usually indicate?
A. Allergy
B. Autoimmune disease
C. Bacterial infection
D. Parasitic infection
Answer: B. Autoimmune disease
Explanation: Antinuclear antibodies (ANA) are often present in autoimmune conditions like lupus.
9. Which immunoglobulin can cross the placenta?
A. IgA
B. IgE
C. IgM
D. IgG
Answer: D. IgG
Explanation: IgG is the only immunoglobulin capable of crossing the placenta, providing passive immunity to the fetus.
10. The most abundant antibody in the blood is:
A. IgD
B. IgM
C. IgA
D. IgG
Answer: D. IgG
Explanation: IgG constitutes about 75% of serum immunoglobulins, making it the most abundant.
🟡 Medium (11–20)
11. Which test is commonly used to detect rheumatoid factor?
A. ELISA
B. Latex agglutination
C. Immunodiffusion
D. Immunoelectrophoresis
Answer: B. Latex agglutination
Explanation: Latex agglutination is a simple, rapid method for detecting rheumatoid factor in serum.
12. In the complement cascade, which component is central to both the classical and alternative pathways?
A. C1
B. C3
C. C5
D. C9
Answer: B. C3
Explanation: C3 is a pivotal point in both pathways and is essential for downstream effects like opsonization and cell lysis.
13. The major histocompatibility complex (MHC) is important in:
A. Platelet aggregation
B. Hemoglobin production
C. Antigen presentation
D. Blood pressure regulation
Answer: C. Antigen presentation
Explanation: MHC molecules present antigen fragments to T cells, a key step in initiating the adaptive immune response.
14. An anamnestic response refers to:
A. A delayed allergic reaction
B. The primary immune response
C. The enhanced secondary immune response
D. Antibody breakdown
Answer: C. The enhanced secondary immune response
Explanation: This rapid and strong response is due to memory cells formed after initial exposure.
15. In a precipitation reaction, maximum precipitation occurs at:
A. Antigen excess
B. Antibody excess
C. Equivalence zone
D. Postzone
Answer: C. Equivalence zone
Explanation: Precipitation occurs most effectively when antigen and antibody are present in optimal proportions.
16. What method is used in nephelometry?
A. Light absorption
B. Light scattering
C. Color change
D. Fluorescence
Answer: B. Light scattering
Explanation: Nephelometry measures light scattered by antigen-antibody complexes in solution.
17. Which antibody class is primarily found in mucosal secretions?
A. IgG
B. IgE
C. IgA
D. IgD
Answer: C. IgA
Explanation: IgA plays a major role in mucosal immunity and is found in saliva, tears, and breast milk.
18. A patient with systemic lupus erythematosus (SLE) is most likely to have:
A. Anti-dsDNA antibodies
B. Anti-RNA antibodies
C. HBsAg
D. Rheumatoid factor
Answer: A. Anti-dsDNA antibodies
Explanation: Anti-dsDNA is a hallmark autoantibody for SLE, often used for diagnosis and monitoring.
19. What does a positive heterophile antibody test suggest?
A. Hepatitis
B. Mononucleosis
C. HIV
D. Tuberculosis
Answer: B. Mononucleosis
Explanation: Heterophile antibodies are associated with Epstein-Barr virus (EBV), the cause of infectious mononucleosis.
20. What is the principle of ELISA?
A. Electrophoresis
B. Antigen-antibody reaction with enzyme-linked detection
C. Cell lysis
D. Fluorescent tagging of DNA
Answer: B. Antigen-antibody reaction with enzyme-linked detection
Explanation: ELISA relies on enzyme-linked antibodies to detect specific antigens or antibodies with a color change.
🔴 Hard (21–25)
21. Which of the following antibodies is typically found in warm autoimmune hemolytic anemia?
A. Cold agglutinins
B. IgE
C. IgA
D. IgG
Answer: D. IgG
Explanation: IgG antibodies react at body temperature and are involved in warm autoimmune hemolysis.
22. In a competitive immunoassay, what does a lower signal indicate?
A. Higher analyte concentration
B. More antibody binding
C. No reaction
D. Decreased background noise
Answer: A. Higher analyte concentration
Explanation: In competitive assays, the target analyte competes with a labeled analog. A lower signal means more analyte is present.
23. Which cytokine is critical in promoting B cell differentiation?
A. IL-1
B. IL-2
C. IL-4
D. IFN-gamma
Answer: C. IL-4
Explanation: IL-4 stimulates B cell growth and is involved in class switching to IgE and IgG1.
24. In flow cytometry, forward scatter (FSC) measures:
A. Cell granularity
B. Antigen expression
C. Cell size
D. DNA content
Answer: C. Cell size
Explanation: FSC gives information about cell size, while side scatter (SSC) indicates complexity or granularity.
25. Which autoimmune disease is associated with anti-CCP antibodies?
A. Systemic lupus erythematosus
B. Rheumatoid arthritis
C. Sjögren’s syndrome
D. Hashimoto’s thyroiditis
Answer: B. Rheumatoid arthritis
Explanation: Anti-CCP (cyclic citrullinated peptide) antibodies are highly specific markers for rheumatoid arthritis.
RESOURCES :
Rodak’s Hematology: Clinical Principles and Applications – Elsevier
Tietz Fundamentals of Clinical Chemistry and Molecular Diagnostics – Elsevier
Clinical Immunology and Serology: A Laboratory Perspective (3rd or 4th ed.) – Christine Dorresteyn Stevens
ASCP BOC Study Guide – Clinical Laboratory Certification Examinations
Henry’s Clinical Diagnosis and Management by Laboratory Methods – Elsevier
Immunology: A Short Course – Coico & Sunshine
CDC, NIH, and WHO online immunology/serology guidelines