Tuberculin (Mantoux) Test MCQ Quiz | Procedures & Instruments

1. What is the specific substance injected in the Mantoux test?

• Live attenuated M. tuberculosis
• Purified Protein Derivative (PPD)
• Killed M. bovis (BCG)
• Recombinant TB antigens (ESAT-6)

2. The Tuberculin test is administered via which route?

• Intramuscular
• Subcutaneous
• Intradermal
• Intravenous

3. What is the standard site for a Mantoux test injection?

• Dorsal aspect of the forearm
• Volar aspect of the forearm
• Deltoid region
• Antecubital fossa

4. What is the standard dose of PPD-S (Purified Protein Derivative – Standard) used in the Mantoux test?

• 1 Tuberculin Unit (TU)
• 5 Tuberculin Units (TU)
• 10 Tuberculin Units (TU)
• 250 Tuberculin Units (TU)

5. What is the volume of fluid injected in a standard Mantoux test?

• 0.01 ml
• 0.1 ml
• 0.5 ml
• 1.0 ml

6. When should the Mantoux test reaction be read for a definitive result?

• Within 6 hours
• At 24 hours
• Between 48 and 72 hours
• After 7 days

7. What is measured to interpret the Mantoux test result?

• Diameter of erythema (redness)
• Diameter of induration (hardness)
• Presence of vesiculation
• Area of the entire reaction site

8. For an HIV-positive patient, what is the minimum induration size considered positive?

• ≥ 5 mm
• ≥ 10 mm
• ≥ 15 mm
• Any palpable induration

9. In a person with no known risk factors for TB, what induration size is generally considered positive?

• ≥ 5 mm
• ≥ 10 mm
• ≥ 15 mm
• ≥ 20 mm

10. For recent immigrants from high-prevalence countries or IV drug users, what induration size is considered positive?

• ≥ 5 mm
• ≥ 10 mm
• ≥ 15 mm
• Any visible reaction

11. The Mantoux test is an example of which type of hypersensitivity reaction?

• Type I (Anaphylactic)
• Type II (Cytotoxic)
• Type III (Immune Complex)
• Type IV (Delayed-type)

12. Which cells are primarily responsible for the induration seen in a positive Mantoux test?

• B-lymphocytes and plasma cells
• Neutrophils and Eosinophils
• T-lymphocytes and Macrophages
• Mast cells and Basophils

13. Which of the following can cause a false-positive Mantoux test?

• Recent viral infection (e.g., measles)
• Infection with non-tuberculous mycobacteria
• Severe malnutrition
• Sarcoidosis

14. A false-negative Mantoux test can be caused by which of the following conditions?

• Recent BCG vaccination
• Infection with M. kansasii
• Anergy due to severe immunosuppression
• Improper measurement of erythema instead of induration

15. How does prior Bacille Calmette-Guérin (BCG) vaccination typically affect the interpretation of a Mantoux test?

• It has no effect on the test result
• It can cause a mild-to-moderate false-positive reaction
• It consistently leads to false-negative results

16. What is the “booster phenomenon” in tuberculin testing?

• A severe local reaction caused by a high dose of PPD
• An increase in reaction size on a second test due to boosting waned immunity
• A systemic reaction including fever and malaise after the test
• The conversion of a negative test to positive due to a new infection

17. In which population is two-step tuberculin testing primarily recommended?

• Children under 5 years of age
• Pregnant women
• Healthcare workers undergoing initial baseline screening
• Patients with suspected active TB disease

18. What does PPD, the antigen used in the test, stand for?

• Potent Polysaccharide Derivative
• Partial Protein Determinant
• Purified Protein Derivative
• Primary Peptide Determinant

19. A positive Mantoux test primarily indicates…

• Active, contagious tuberculosis disease
• Successful BCG vaccination
• A cellular immune response to mycobacterial antigens
• Presence of antibodies against M. tuberculosis

20. Which in-vitro test is an alternative to the TST and is not affected by BCG vaccination?

• Chest X-ray
• Sputum smear microscopy
• Interferon-Gamma Release Assay (IGRA)
• Tuberculin antibody test

21. During the administration of the PPD, the needle bevel should be facing…

• Downwards
• Upwards
• Sideways
• The direction does not matter

22. What is the immediate visible sign of a correctly administered Mantoux test?

• A small bruise
• Immediate redness (erythema)
• A distinct, pale wheal of 6-10 mm diameter
• A drop of blood at the injection site

23. How should the induration be measured for interpretation?

• Longitudinally along the axis of the forearm
• Transversely to the long axis of the forearm
• By measuring the circumference of the reaction
• By averaging the longitudinal and transverse diameters

24. Which of the following is a contraindication for performing a Mantoux test?

• A history of BCG vaccination
• Current pregnancy
• A previous severe reaction (e.g., blistering, necrosis) to a TST
• Age below 1 year

25. What is a major limitation of the Mantoux test?

• It has very low sensitivity in immunocompetent individuals
• It cannot distinguish between latent TB infection and active TB disease
• The results are available only after several weeks
• It requires a large volume of blood sample