This document provides guidance on occupational exposure to tuberculosis (TB) for healthcare workers. It discusses latent TB infection, including what it is, who should be screened, and how to treat it. It also compares latent TB to active TB disease. The document recommends screening high-risk groups for latent TB with tuberculin skin tests. It provides criteria for determining positive skin test reactions and guidelines for treating latent TB infection with medications like isoniazid. The document concludes with recommendations from CDC and WHO on preventing TB transmission in healthcare settings through administrative, environmental and personal protective equipment controls.

1. Occupational Exposure to TB
Dr. Faisal Al Haddad
Consultant of Family Medicine &
Occupational Health
Director of Saudi Board Program
CBAHI Surveyor

2. Latent TB Infection
 What is Latent TB infection?
 Candidates for Screening
 Positive Tuberculin Skin Test
 Treatment of Latent TB infection

3. Latent TB Infection
 Latent TB infection refers to a condition that occurs after initial
infection with M.TB
 Within 2-12 weeks after the initial infection, the immune
response limits additional multiplication of the tubercle bacilli &
test results for M.TB infection become positive.
 Certain bacilli remain in the body & viable for multiple years.
 These persons are asymptomatic and not infectious.

4. Latent versus Active TB
Latent TB Infection TB Disease
Skin test or blood test result
indicating TB infection
Skin test or blood test result
indicating TB infection
Normal chest x-ray
Negative sputum test
Abnormal chest x-ray
Positive sputum smear or culture
Alive but inactive TB bacteria in the
body
Active TB bacteria in the body
Asymptomatic May have symptoms (e.g. coughing,
fever, weight loss(
Cannot spread TB bacteria to others May spread TB bacteria to others
Needs treatment for latent TB
infection to prevent TB disease
Needs treatment to treat TB disease

5. Screening for Latent TB
 TST should be done for those at risk for acquiring TB so that
treatment of LTBI can be instituted to prevent the development
of active disease.
– HCP
– nursing home residents and employees
– immigrants from areas with high endemic rates of TB
– IV drug users
– homeless persons
– patients with HIV, end-stage renal disease, diabetes, or other
immunosuppressing diseases
 People exposed to a patient with active TB should be tested.

6. Positive Tuberculin Test Reactions
Induration Size Group
≤5mm • HIV-positive persons
• Recent contacts of TB case
• Fibrotic changes on CXR consistent with old TB
• Patients with organ transplants and other
immunosuppressed patients (≥ 15 mg/day
prednisone for 1 month(

7. Positive Tuberculin Test Reactions
Induration
Size
Group
10mm • Recent arrivals (< 5 years( from high-prevalence countries
• Injection drug users
• Residents & employees of high-risk settings
• Mycobacteriology lab personnel
• Persons with high-risk clinical conditions
• Medically underserved high-risk minorities
≤15mm • Persons with no risk factors for TB

8. Treatment of Latent TB Infection
 All persons found to have a positive TST or IGRA should be
evaluated for the presence of active TB.
– HX of exposures to TB & symptoms suggestive of TB
– Lung examination
– CXR
 Patients with a suggestive CXR or symptoms should have three
sputum specimens collected for AFB stain & culture.
 Treatment of LTBI should be withheld in such patients until
cultures are negative to prevent treating active TB with only a
single drug.

9. Treatment of Latent TB Infection
 All persons who have had a negative skin test within the previous
two years and who now have a positive test (recent converters)
should be treated for LTBI.
 In patients who are at risk for TB, positive TST is considered an
indication for treatment even if the TST is not a recent
conversion.
 Patients at risk for TB:
– patient with HIV, DM, ESRD
– patients on steroids or other immunosuppressive drugs
– recent contacts of patients with active TB
– immigrants from areas with high endemic rates of TB

10. Treatment of Latent TB Infection
Isoniazid/INH (Drug of Choice):
5 mg/kg (up to 300 mg) OD for 9 months
Monitor patient for symptoms of hepatitis at least monthly.
AST/ALT for any patient who reports symptoms of drug-induced hepatitis
INH therapy should be stopped in:
– symptomatic patient with AST/ALT >3 times the upper limit of normal
– asymptomatic patient with AST/ALT >5 times the upper limit of normal
Pyridoxine should be given to all patients with poor nutrition or at
increased risk for developing peripheral neuropathy

11. Treatment of Latent TB Infection
Rifampin
Patients who cannot take INH
Patients whose positive skin test has a high likelihood of being caused
by INH-resistant MTB (e.g., recent converters after an exposure to a
patient with INH-resistant TB)
10 mg/kg (max 600 mg) OD for 4 months.
Rifapentine+INH
The combination of rifapentine and INH weekly for 12 weeks has been
proposed as an alternative to INH.

12. CDC Recommendations for Preventing
TB Transmission in Healthcare Settings
Administrative controls
Assign responsibility for TB infection control
Conducting TB risk assessment
Disseminate written TB infection control plan to detect, isolate
(airborne), and treat suspected or confirmed TB cases
Timely availability, testing, and reporting of testing to infection control
and ordering provider
Effective practices for management of suspected or confirmed TB cases

13. CDC Recommendations for Preventing
TB Transmission in Healthcare Settings
 Proper cleaning and disinfection of contaminated equipment
 Train HCP on TB prevention, transmission, and symptoms
 Screening and management program of HCP at risk for, with, or
exposed to TB
 Use epidemiology-based prevention principles such as using setting
related infection data
 Use signs advising proper infection control practices (i.e., respiratory
hygiene and cough etiquette)
 Coordinate with local or state health department efforts to control TB

14. CDC Recommendations for Preventing
TB Transmission in Healthcare Settings
Environmental controls/ PPE
Develop and implement a respiratory protection program
Train HCP on respiratory protection and patients on respiratory hygiene
and cough etiquette
Use and availability of negative-pressure rooms based on risk
assessment (ongoing monitoring of negative-pressure ventilation rooms)
UV light may be used in addition to appropriate ventilation

15. WHO Recommendations for Preventing
TB Transmission in Healthcare Settings
Administrative controls
Develop facility plan for TB control, promote local coordinating bodies for
TB prevention/control
Optimize use of available spaces and consider renovation or additional
construction to optimize implementation of controls
On-site surveillance of TB among HCP; assess the facility
Advocacy, communication, and social mobilization for patients, HCP,
and visitors

16. WHO Recommendations for Preventing
TB Transmission in Healthcare Settings
 Evaluate and monitor TB control measures
 Participate in research
 Triage, separation of TB patients, infection control strategies (cough
etiquette/respiratory hygiene), and decrease time in healthcare facility
 Prevention of HIV for HCP, ART for those who are positive, and LTBI
and TB treatment
 Rapid testing, shorter turnaround time of testing, parallel rather than
sequential investigation of cases and use of algorithms

17. WHO Recommendations for Preventing
TB Transmission in Healthcare Settings
Environmental controls/ PPE
Use of respirators
Ventilator systems: ideally 12 air exchanges per hour
UV light irradiation when appropriate/ventilation not available

18. WHERE?

19. Initial Testing on Employment
 It is important that all HCP have a TST or IGRA on employment
to establish a baseline with which subsequent tests can be
compared.
 This will prevent mislabeling a positive test after a TB exposure
as a skin test conversion.
 A baseline TST (or IGRA) should be completed regardless of
history of BCG vaccination.
 The TST should administered and read by properly trained
personnel.

20. Initial Testing on Employment
 Newly hired HCP who have a history of a positive TST or IGRA
should provide written proof of their result for appropriate
documentation and follow-up.
 If an employee has had a positive test, check :
– Whether the employee has been screened for active TB
– CXR results
– Whether treatment of LTBI was completed
 The test-positive HCP should be educated regarding symptoms
of active disease and how, when, and where to report
symptoms if they develop.

21. Initial Testing on Employment
 HCP with a negative initial TST and who do not have
documentation of a previous negative within the prior 12
months should receive a second TST (two-step) at least 1
week later to assess for the booster phenomenon.
 The booster phenomenon occurs because a person’s reaction
to tuberculin PPD can wane with time, and therefore the initial
TST may be negative.
 Unlike TST, IGRA requires a single visit for a test, as no
booster phenomenon is needed for an accurate result.

22. Recurrent HCP Testing
The need for and frequency of routine recurrent TST or IGRA
depend on the risk to the HCP in a given area at a given
healthcare facility.
Low-risk settings:
Perform TST or IGRA only at the time of hire and may choose not
to do recurrent testing.
Medium-risk settings:
Perform annual testing of all HCP who work in certain areas of the
facility.

23. Recurrent HCP Testing
Potential ongoing transmission:
perform TST or IGRA every 8-10 weeks until lapses in infection
prevention have been corrected and no additional evidence of
ongoing transmission is apparent.
Once it is determined that ongoing transmission has ceased, the
setting should be reclassified as medium risk.

24. Risk Classifications for Healthcare
Settings
Setting Low Risk Medium Risk Potential
Ongoing
Transmission
Inpatient <200
beds
<3 TB patients/year ≥3 TB patients/year
Evidence of
ongoing MTB
transmission,
regardless of
setting
Inpatient ≥200
beds
<6 TB patients/year ≥6 TB patients/year
Outpatient &
nontraditional
facility-based
<3 TB patients/year ≥3 TB patients/year
Laboratories Laboratories in which
clinical specimens that
might contain MTB are
not manipulated
Laboratories in which
clinical specimens that
might contain MTB are
manipulated

25. Risk Classifications for Healthcare
Settings
Setting Low Risk Medium Risk Potential
Ongoing
Transmission
TB
treatment
facilities
Setting in which:
•Persons who will be treated have
been demonstrated to have LTBI and
not TB
•A system is in place to triage
persons who have signs or
symptoms of TB to a setting in which
persons with TB are treated
•No cough-inducing or aerosol-
generating procedures are performed
Settings in which:
•Persons with TB
are encountered
•Criteria for low risk
is not otherwise met
Evidence of
ongoing MTB
transmission
regardless of
setting

26. Management of HCP with positive
TST or IGRA
 All persons found to have a positive TST or IGRA should be
evaluated for the presence of active TB (exposures to TB,
symptoms of TB, Lung examination, CXR)
 Patients with a suggestive CXR or suggestive symptoms
should have three sputum specimens collected for AFB stain
and culture.
 The healthcare facility should provide INH to HCP if treatment
of LTBI is indicated to reduce the risk of active TB.

27. Management of HCP with positive
TST or IGRA
 HCP who have had a positive TST or IGRA do not need further
testing, as these do not provide any useful additional information.
 At the time of annual testing, all HCP with a history of a positive
test should complete a questionnaire to ensure that they are not
experiencing common symptoms of TB
 A positive answer to any question should prompt further
evaluation.
 The HCP should also be reminded to notify OH if any of these
symptoms occur in the future.

28. Management of Healthcare
Exposures
 Identification of Exposed Persons
 Testing TB Contacts (TST or BAMT)

29. Identification of Exposed Persons
Source Patient
Potentially Infectious
– Evidence of lung or laryngeal disease even if sputum
samples were AFB smear negative
Non Infectious
– No evidence of pulmonary disease by radiograph and
symptom review
– Sputum samples show no AFB

30. Testing TB Contacts
 If the patient is thought to be infectious, a list should be developed of
all close contacts
 Patients who shared a room with the source patient & HCP who had
the most frequent or extensive contact should have a TST/BAMT
within 2 weeks of exposure, to establish baseline results
 After initial testing, exposed patients & HCP should be retested in 8 to
12 weeks.
 If the patients and HCP with the greatest degree of exposure have any
skin test conversions or positive BAMT results, then patients, visitors,
and HCP with lesser degrees of exposure should be tested.

31. Practice
The infection preventionist is assisting Employee Health with personnel TB
skin testing. Which of the following represents a known TST conversion in a
HCW?
a. Prior tuberculin test results are not available, but the current result is 16
mm after 48 hours
b. Tuberculin reaction 1 year ago was 9 mm, and the current results are 13
mm
c. A prior tuberculin reaction was not measured, but the employee states it
was dime-sized. The current result is 11 mm
d. Tuberculin reaction 1 year ago was 3 mm, and the current result is 18mm

32. Practice
Which of the following are acceptable methods for follow-up testing among
healthcare personnel with unprotected exposure to TB?
1)QuantiFERON-TB Gold testing (QFT-G) of sputum at the time of exposure and
12 weeks after exposure
2)QFT-G testing of blood at the time of exposure and 12 weeks after exposure
3)TST via tine tests at the time of exposure and 12 weeks after exposure
4)TST via the intradermal method at the time of exposure and 12 weeks after
exposure
5)Chest radiograph for personnel with prior positive TST or QFT-G results
6)Chest radiograph for symptomatic personnel with positive TST or QFT-G results
a. 1, 3, 6
b. 2, 3, 5
c. 1, 4, 6
d. 2, 4, 6

33. Thank you