TB Test Infection Control and Prevention 1 — Questions and Answers
Question 1: Which ventilation feature of an airborne infection isolation room (AIIR) is most critical for preventing the spread of Mycobacterium tuberculosis to adjacent areas?
- Positive pressure ventilation
- Negative pressure ventilation (Correct answer)
- HEPA-filtered supply air only
- Increased humidity control
Correct answer: Negative pressure ventilation
Negative pressure in an AIIR ensures that air flows into the room rather than out, preventing infectious droplet nuclei from escaping into corridors or adjacent spaces.
Question 2: According to CDC guidelines, what is the minimum number of air changes per hour (ACH) recommended for existing airborne infection isolation rooms used for TB patients?
- 4 ACH
- 6 ACH
- 12 ACH (Correct answer)
- 20 ACH
Correct answer: 12 ACH
CDC recommends a minimum of 12 ACH for existing AIIRs to adequately dilute and remove infectious aerosols; new construction should achieve at least 12 ACH as well.
Question 3: What is the primary route of transmission of Mycobacterium tuberculosis from an infectious person to a susceptible host?
- Direct contact with infected skin lesions
- Fecal-oral route through contaminated food or water
- Inhalation of airborne droplet nuclei (Correct answer)
- Vector-borne transmission through insect bites
Correct answer: Inhalation of airborne droplet nuclei
M. tuberculosis spreads almost exclusively through inhalation of tiny droplet nuclei (1–5 microns) that remain suspended in air after an infectious person coughs, sneezes, sings, or speaks.
Question 4: Which respiratory protection device is the minimum standard recommended by CDC for healthcare workers entering a room with a suspected or confirmed pulmonary TB patient?
- Standard surgical mask
- N95 filtering facepiece respirator (Correct answer)
- Powered air-purifying respirator (PAPR)
- Full-face elastomeric respirator
Correct answer: N95 filtering facepiece respirator
A NIOSH-certified N95 filtering facepiece respirator is the minimum recommended protection, as it filters at least 95% of airborne particles including M. tuberculosis droplet nuclei.
Question 5: Which of the following is classified as an aerosol-generating procedure that significantly increases risk of TB transmission and requires enhanced precautions?
- Measuring a patient's blood pressure
- Performing bronchoscopy on a TB patient (Correct answer)
- Administering oral TB medications
- Conducting a TB skin test reading
Correct answer: Performing bronchoscopy on a TB patient
Bronchoscopy is an aerosol-generating procedure that can dramatically increase aerosolization of M. tuberculosis, requiring use of an N95 or higher respirator and performance in a negative-pressure room.
Question 6: When can a patient with confirmed infectious pulmonary TB be safely removed from airborne infection isolation according to CDC criteria?
- After fever and cough have resolved for 48 hours
- After 3 consecutive negative AFB sputum smears collected on different days (Correct answer)
- After completing a minimum of 2 weeks of antibiotic therapy
- After chest X-ray shows marked improvement
Correct answer: After 3 consecutive negative AFB sputum smears collected on different days
CDC recommends patients remain in airborne isolation until 3 consecutive negative AFB sputum smears are obtained from specimens collected 8–24 hours apart, with at least one early-morning specimen.
Question 7: A healthcare worker needs to enter a TB isolation room. What is the correct sequence for donning personal protective equipment?
- Gloves, then N95 respirator, then gown
- N95 respirator, then gown, then gloves
- Gown, then gloves, then N95 respirator
- N95 respirator first, order of remaining PPE per facility protocol (Correct answer)
Correct answer: N95 respirator first, order of remaining PPE per facility protocol
The N95 respirator must be donned first to ensure protection against airborne transmission before the worker is exposed; the remaining PPE is applied per facility protocol.
TB Test Infection Control and Prevention 1
Which ventilation feature of an airborne infection isolation room (AIIR) is most critical for preventing the spread of Mycobacterium tuberculosis to adjacent areas?