1. APIC Greater NY Chapter 13 Q&A Session
Jason Thomas, RN, BSN
Mount Sinai Hospital
Dept. of Infection Prevention

2. 1. Five days after admission for pneumonia, a patient is diagnosed with active cavitary pulmonary tuberculosis.  Which of the following staff is MOST likely to have a TST conversion?
dietary employees who delivered the meal trays
the nursing assistant who fed the patient
housekeeping staff who mopped the floor in the patient's room
engineering staff who repaired the patient's call light

3. Correct Answer: the nursing assistant who fed the patient (B) Rationale: The nursing assistant had an extended duration of exposure in comparison to the other 3 scenarios.
Mount Sinai / Presentation Slide / October 27, 2014

4. 2. Which is true about a tuberculin skin test (TST)?
Positive TST indicates active tuberculosis (TB) infection
Negative TST rules out active TB infection
Positive TST indicates past exposure to TB
Negative TST indicates past exposure to TB
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5. Correct Answer: ( C ) Positive TST indicates past exposure to TB Rationale: TST involves injection of purified protein-derived from the mycobacterial cell wall. The test relies on the fact that persons who have been infected with TB will have a delayed-type hypersensitivity reaction to this reagent. The TST is a screening tool to detect people with latent TB infection (LTBI); it cannot be used for ruling in or ruling out active TB. This is because a positive TST merely indicates a history of LTBI at some point in the past. It conveys no information regarding the current status of the person’s infection. Likewise, a negative test does not rule out active TB because people with active tuberculosis may well have a negative TST, even in the presence of positive controls. In fact, up to 20 percent of persons with active TB will have negative TST results
Reference: APIC text, 4th edition, Chapter 95- Tuberculosis and other Mycobacteria
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6. First thing in the morning After a Respiratory treatment
3. The optimal time to collect a sputum specimen for acid fast bacilli (AFB) testing to rule out TB would be:
First thing in the morning
After a Respiratory treatment
Prior to the patient going to bed
Prior to a respiratory treatment
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7. Correct answer: (A) First thing in the morning
Correct answer: (A) First thing in the morning. Rationale: Because pulmonary disease is the most common form of TB, patients with suspected TB should have a chest radiograph. If the radiograph is abnormal or the patient has respiratory complaints, sputum specimens should be collected for acid- fast bacilli (AFB) staining, culture, or other direct tests. The first sputum may be obtained on admission, but subsequent cultures are usually obtained in the morning on consecutive days. A total of three specimens collected on separate days is generally adequate, and once one specimen is AFB positive, subsequent samples are not needed. Specimens should be delivered promptly to the laboratory for processing.
Reference: APIC text, 4th edition, Chapter 95- Tuberculosis and other Mycobacteria
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8. 4. During annual TST, an employee’s test result was read as 10mm induration. The employee’s last TST was negative. This initial result indicates a:
Positive test
False positive
Negative test
False negative
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9. Correct answer: (A) Positive test Rationale: A positive test is determined by the number of MM of induration (not erythema) caused by the reaction of to the tuberculin. Different cut points are used depending on the likelihood of the individual having a TB infection and the likelihood that the infection, if present, will progress to active TB. A 10mm reaction in a healthcare worker is considered a positive test. All healthcare personnel with positive baseline TST results should be referred for medical and diagnostic evaluation; additional skin testing is not needed.
Reference: Jensen PA, Lambert LA, Lademarco MF, et al. Guidelines for Preventing the Transimission of Mycobacterium tuberculosis in Health-Care Settings, MMWR 2005 December (RR-17)
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10. 5. Which of the following Statements about TB and airborne disease among homeless individuals is most accurate?
a. Most TB infections among homeless individuals are reactivations of established disease. b. Sputum testing detects more than 90 percent of patients with TB c. Screening for TB with chest X-ray may be the most cost- effective approach d. Directly observed therapy in the acute hospital setting is associated with the highest completion rates
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11. Correct answer: ( C ) Screening for TB with chest X- ray may be the most cost- effective approach Rationale: TB incidence is higher in the homeless populations than in the general population. Molecular epidemiology studies indicate that most TB cases occurring in the homeless are primary infections. The spread of TB among the homeless is related to recent person to person transmission, which produces outbreaks with large clusters in which more than 50 percent of persons are infected. Homeless shelters are major sites of transmission. Screening by chest radiography either periodically in all residents or specifically in symptomatic persons (eg. Chronic coughers) appears to be the most cost effective approach for TB detection and diagnosis in this population
Reference: APIC test, 4th edition, Chapter 95- Tuberculosis and other Mycobacteria
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12. An approved mask is necessary for respiratory protection
6. An autopsy is ordered on a patient who was diagnosed with tuberculosis (TB). Which of the following statements is correct regarding postmortem care of a deceased TB patient?
Autopsy rooms should be at positive pressure with respect to adjacent areas, and room air must be exhausted directly outside
An oscillating autopsy saw should be used to reduce the infectious aerosols
An approved mask is necessary for respiratory protection
Standard precautions are sufficient because Mycobacterium tuberculosis needs a living host to survive
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13. Correct answer: ( C ) An approved mask is necessary for respiratory protection Rationale: OSHA classifies performance of an autopsy on a known or suspected case of TB to be a high-hazard procedure requiring personnel to use approved respiratory protection. In areas where TB is prevalent and the health history is unknown, respiratory protection is prudent, especially for medical examiner’s cases. *Autopsy rooms should be negatively pressured to prevent the migration of infectious particles (TB in this case) into the adjacent space. *The use of any saw will result in aerosolized particles which is not ideal. *TB Particles can survive in the air for sometime which is why hospitals institute engineering controls (negative pressure rooms etc.)
Reference: APIC test, 4th edition, Chapter 65- Postmortem Care
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14. At least 15 to 20 air exchanges per hour Direct exhaust to the outside
7. Which of the following does not meet the requirements for an airborne isolation room?
Negative airflow isolation room (negative air pressure relative to corridor)
At least 15 to 20 air exchanges per hour
Direct exhaust to the outside
Daily monitoring of the air pressure with visual indicators
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15. Correct answer: ( B) At least 15 to 20 air exchanges per hour Rationale: Airborne precautions are used to prevent transmission of infectious organisms that remain suspended in the air and travel great distances. These diseases include measles, smallpox, chickenpox, pulmonary tuberculosis, avian influenza, and possibly SARS- associated coronavirus. In acute care and long term care settings, patients should be placed in an airborne infection isolation room (AIIR) with negative air pressure relative to the corridor and at least 6 to 12 air exchanges with direct exhaust of air to the outside. Air pressure should be monitored daily with visual indications (eg, smoke tubes, flutter strips). The door should be kept shut.
Reference: APIC test, 4th edition, Chapter 29- Isolation Precautions (Transmissions-Based Precautions)
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16. Tuberculin reaction 1 year ago was 3mm, and the current is 18mm
8. The Infection Preventionist (IP) is assisting Employee Health with personnel tuberculosis (TB) skin testing. Which of the following represents a known tuberculin skin test (TST) conversion in a healthcare worker?
Prior tuberculin test results are not available, but the current results is 16mm after 48hrs
Tuberculin reaction 1 year ago was 2mm, and the current results are 9mm
A prior tuberculin reaction was not measured, but the employee states it was dime sized. The current results is 11mm
Tuberculin reaction 1 year ago was 3mm, and the current is 18mm
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17. Correct answer: ( D ) Tuberculin reaction 1 year ago was 3mm, and the current result is 18mm Rationale: Interpretation of the TST depends on measured TST induration in millimeters, the person’s risk for being infection with M. Tuberculosis, and risk for progression to active TB if infected. The TST test should be interpreted according to the CDC guidelines. A healthcare worker without known exposure who demonstrates an increase to ≥ 10mm is considered a positive result.
Reference:
APIC text, 4th edition, Chapter 95 – Tuberculosis and other Mycobacteria
APIC text, 4th edition, Chapter 100- Occupational Health
Mount Sinai / Presentation Slide / October 27, 2014