Evaluation of Tuberculin 

Skin Test Conversions at a 

Mississippi Fire Department 

John Gibbins DVM, MPH 

Elena Page MD, MPH 

Meridian, Mississippi 

August 2007 

National Institute for Occupational 

Safety and Health 

Health Hazard Evaluation Report 

HETA 2007-0012-3046 

City of Meridian Fire Department 

DEPARTMENT OF HEALTH AND HUMAN SERVICES 

Centers for Disease Control and Prevention 

Workplace 

Safety and Health
The employer shall post a copy of this report 

for a period of 30 calendar days at or near 

the workplace(s) of affected employees. The 

employer shall take steps to insure that the 

posted determinations are not altered, defaced, 

or covered by other material during such 

period. [37 FR 23640, November 7, 1972, as 

amended at 45 FR 2653, January 14, 1980]. 
Contents

RepoRt Contents


Abbreviations........................................................................ii


Highlights.of.the.NIOSH.Health.Hazard.Evaluation............. iii


Summary.............................................................................iv


Introduction...........................................................................1


Assessment..........................................................................2


Results.and.Discussion........................................................3


Conclusions..........................................................................5


Recommendations................................................................6


References...........................................................................8


Appendix Evaluation.Criteria..............................................................10


ACknowledgments Acknowledgements.and.Availability.of.Report....................13


Health Hazard Evaluation Report 2007-0012-3046 Page  
AbbReviAtions

BCG Bacillus Calmette-Guerin 

CDC Centers for Disease Control and Prevention 

EMS Emergency medical services 

HHE Health hazard evaluation 

LTBI Latent tuberculosis infection 

mm Millimeter 

NAICS North American Industry Classification System 

NFPA National Fire Protection Association 

NIOSH National Institute for Occupational Safety and Health 

OSHA Occupational Safety and Health Administration 

TB Tuberculosis 

TST Tuberculin skin test 

Page  Health Hazard Evaluation Report 2007-0012-3046 
HigHligHts of tHe 

niosH HeAltH 

HAzARd evAluAtion 

Health (NIOSH) received a 

(HHE) at the Meridian Fire 

Chief submitted the 

HHE request because 12 

October and December 

2006. 

The National Institute for 

Occupational Safety and 

management request for 

a health hazard evaluation 

Department in Meridian, 

Mississippi. The Fire 

firefighters tested positive 

for latent tuberculosis 

infection on their 

tuberculin skin tests (TST) 

from 2005–2006. NIOSH 

investigators conducted 

an investigation in 

What NIOSH Did 

● We talked with firefighters about their risk factors for 

tuberculosis infection. 

● We interviewed management, union officials, district health 

officials, and medical staff at a local hospital that provides the 

Department’s medical exams. 

● We did blood tests for tuberculosis infection on the 12 

firefighters with positive skin tests. 

● We repeated skin tests on 10 firefighters with a different brand 

of tuberculin solution. 

What NIOSH Found 

● All 12 firefighter’s blood tests were negative for tuberculosis 

infection. 

● Firefighter risk for tuberculosis infection was low according to 

Centers for Disease Control and Prevention (CDC) guidelines. 

● The local hospital’s tuberculosis testing program did not follow 

CDC guidelines. 

● Many firefighters missed appointments for skin test result 

reading, which contributed to program discrepancies. 

What Meridian Fire Department Management

Can Do 

● Ensure trainees and new employees receive two-step tuberculosis 

skin testing or QuantiFERON®-TB Gold blood testing when 

hired. 

● Continue to provide training on tuberculosis and other 

infectious diseases to firefighters. 

● Continue to provide N95 respirators for firefighter use and 

provide training and fit-testing for all firefighters. 

What Meridian Firefighters Can Do 

● Know the signs and symptoms of tuberculosis infection, and 

wear N95 respiratory protection on EMS calls when indicated. 

● Attend scheduled medical appointments to prevent increased 

costs associated with re-scheduling and to prevent getting more 

tuberculosis skin tests than necessary. 

● Report exposures to people with potential tuberculosis 

infection to your supervisors. 

Health Hazard Evaluation Report 2007-0012-3046 Page  
summARy

Mycobacterium 

tuberculosis. 

false-positive results. 

Firefighters were 

not infected with 

Discrepancies in TB 

testing procedures led to 

In October 2006, NIOSH received a management request for 

an HHE at the City of Meridian Fire Department in Meridian, 

Mississippi. The Fire Chief submitted the HHE request because 

12 firefighters tested positive for latent tuberculosis infection 

from 2005–2006. On October 24–26, 2006, NIOSH medical 

investigators conducted a site visit. We held an opening conference 

with management and union representatives to discuss the HHE 

request. We conducted employee interviews and collected blood 

samples for TB testing. Individuals were mailed their blood test 

results on October 31, 2006. 

A follow-up site visit was conducted on December 11–13, 2006. 

NIOSH medical investigators, in conjunction with State of 

Mississippi District 6 Tuberculosis Program staff, conducted followup TSTs for participants to determine their eligibility for future 

TST as part of their medical surveillance program and to help 

confirm the results of our investigation. Individuals were verbally 

notified of their test results at the time of TST interpretation, and 

written results were mailed to participants on December 15, 2006. 

Interviews with Fire Department management, firefighters, District 

6 Tuberculosis Program personnel; and an evaluation of the 

department’s EMS procedures (no patient transport) found the 

department to be at low risk for TB, using CDC guidelines. 

All twelve participants’ blood samples were tested for evidence of 

TB infection using QuantiFERON®-TB Gold methodology; all 

twelve samples tested negative, indicating that these firefighters 

were not infected with Mycobacterium tuberculosis. 

We found discrepancies in the TB screening program at the 

hospital that administered the Fire Department’s occupational 

medical screening program, when compared to CDC 

recommendations. These discrepancies led to the false-positive 

TST results that were confirmed by the blood test and subsequent 

follow-up TST performed in December 2006. 

We recommend two options concerning future tuberculosis 

screening for Meridian Fire Department firefighters. If 

management decides to continue annual tuberculosis screening, it 

should be conducted following CDC guidelines. If management 

decides to conduct an annual TB risk assessment for department 

Page v Health Hazard Evaluation Report 2007-0012-3046 
summARy (Continued) 

firefighters to determine testing frequency, this assessment should 

be conducted with the assistance and close cooperation of the State 

of Mississippi District 6 Tuberculosis Program staff.

 Management and union officials should emphasize the 

importance of attending all medical appointments, continue 

periodic refresher training on tuberculosis and bloodborne 

pathogens, and incorporate N95 respirator training and fit-testing 

into their respiratory protection program. 

Keywords: NAICS 922160 (Fire Protection), firefighters, tuberculosis, 

tuberculin skin test, emergency medical services, healthcare workers 

Health Hazard Evaluation Report 2007-0012-3046 Page v 
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Page v Health Hazard Evaluation Report 2007-0012-3046 
intRoduCtion

In October 2006, NIOSH received a management request for a 

HHE from the Fire Chief at the City of Meridian Fire Department 

in Meridian, Mississippi. This request was prompted by the 

finding that nine firefighters tested positive (≥ 10 mm induration) 

on TST during routine physical exams in the summer of 2006. 

Additionally, three firefighters tested in 2005 had positive TSTs. 

Before 2005, testing was conducted sporadically among limited 

numbers of firefighters with no positive results. An investigation 

was conducted by the State of Mississippi Department of Health 

District 6 Tuberculosis Program personnel. No firefighters were 

diagnosed with active tuberculosis disease; however, they were 

considered to have LTBI and evaluated for drug therapy. Their 

investigation did not identify a source of exposure to a known 

active tuberculosis case. 

The City of Meridian Fire Department is located in Meridian, 

Mississippi (population 40,000), in Lauderdale County in the 

east-central part of the state. The fire department consists of 

seven stations and has approximately 104 firefighters. Personnel 

are divided among three shifts (A, B, and C shifts). Each shift 

is typically on duty for 24 hours, and off duty for 48 hours. In 

addition to fire suppression duties, the firefighters respond to EMS 

calls. Firefighters do not transport patients; all patient transport 

is provided by private ambulance services. Approximately 80% of 

calls involve EMS duties; in 2004, the Department responded to 

3,000 total calls for assistance. 

On October 24–26, 2006, NIOSH medical investigators conducted 

a site visit. We held an opening conference with management and 

union representatives to discuss the HHE request. We conducted 

employee interviews and collected blood samples for TB testing. 

Individual blood test results were mailed to participants on 

October 31, 2006. 

A follow-up site visit was conducted on December 11–13, 2006. 

NIOSH medical investigators, in conjunction with District 

6 Tuberculosis Program staff, conducted follow-up TST for 

participants. Participants were verbally notified of their test results 

at the time of TST interpretation, and written results were mailed 

to participants on December 15, 2006. 

Health Hazard Evaluation Report 2007-0012-3046 Page  
Assessment 

Interviews conducted among the 12 firefighters with positive TSTs 

covered employment, medical, and travel history; place of birth; 

hobbies; and potential association with specific groups considered 

at increased risk for tuberculosis infection, such as those found at 

homeless shelters and prisons. Additionally, we asked questions 

about historical exposure to a known or suspected case of active 

tuberculosis, including both occupational and non-occupational 

exposure. After obtaining written informed consent, blood samples 

were collected in green-top lithium heparin tubes for testing at a 

contract laboratory utilizing QuantiFERON®-TB Gold, an enzymelinked immunosorbent assay test more specific for Mycobacterium 

tuberculosis diagnosis [CDC 2005a]. Blood samples were delivered 

to the contract laboratory in a neighboring state by NIOSH 

personnel to ensure adherence to the 12-hour time requirement 

from blood draw to sample processing as required in the 

QuantiFERON®-TB Gold package insert [Cellestis 2007]. NIOSH 

investigators interviewed medical personnel at a local hospital that 

administers the fire department’s medical surveillance program. 

We reviewed TST historical records for all 104 firefighters, and 

evaluated TST program procedures performed by hospital staff. 

We also met with State of Mississippi Department of Health 

District 6 Tuberculosis Program personnel to discuss the results of 

their investigation and to learn about the incidence and prevalence 

of tuberculosis in Meridian, Lauderdale County, and the state. 

Officials at the Mississippi Department of Health in Jackson 

were consulted for background information on tuberculosis in 

Mississippi and testing and treatment policies at the state level. 

Based on the results obtained from our initial investigation, we 

conducted a second site visit in order to conduct TST among 

available participants, utilizing tuberculin from a different 

manufacturer than was used in 2006 by the contract hospital. 

These tests were administered by a District 6 health department 

nurse in charge of the tuberculosis program, and results were read 

and documented 48–72 hours after placement. This testing was 

conducted to determine the eligibility of firefighters for inclusion 

in future departmental tuberculosis testing programs and to help 

confirm the findings of our investigation. 

Page  Health Hazard Evaluation Report 2007-0012-3046 
Results And disCussion

We interviewed 12 firefighters who had a positive TST. Length of 

employment at the fire department ranged from 1.5 to 20 years, 

with a median length of 7 years. Participants had worked for 

varying periods of time in several of the department’s seven fire 

stations; no common work pattern was found. Firefighters with a 

positive TST were found on all shifts (A-6, B-3, and C-3). Eleven 

of twelve participants were born in Mississippi; one participant 

was born in Louisiana. A history of foreign travel was reported by 

6 of 12 participants; travel was associated with military service or 

vacations in 5 of 6 participants; travel had either occurred years in 

the past or involved limited contact with local populations in most 

cases. Although 6 of 12 participants reported either past or current 

employment involving EMS work at other locations, such as 

volunteer fire departments, none reported involvement in patient 

transport in other than rare occasions. In summary, no common 

source or risk factors for exposure to an individual with active 

tuberculosis were found. 

All 12 participants consented to having a blood sample collected, 

and these samples were tested using QuantiFERON®-TB Gold 

methodology. All twelve samples tested negative, indicating that 

these firefighters were not infected with Mycobacterium tuberculosis. 

Based on these initial results we conducted a follow-up site visit 

on December 11–13, 2006. NIOSH medical investigators, in 

conjunction with District 6 Tuberculosis Program staff, conducted 

follow-up TST for participants, using Tubersol® tuberculin. Out of 

the original 12 participants, 10 were available for this subsequent 

testing: 9 of 10 tested negative. One individual tested positive with 

a result of 14 mm induration. This individual’s result was likely 

due to past exposure to a non-tuberculosis species of mycobacteria, 

commonly found in the Southeastern United States, and not 

detected by QuantiFERON®-TB Gold testing. We recommended 

this individual be deferred from future TST, following CDC 

guidelines [CDC 2005b]. Individuals who test positive on TST will 

likely also be positive if tested in the future, and may have a serious 

reaction to TST or inappropriately be diagnosed as newly infected 

and placed on drug therapy. We recommended the other nine 

people could be included in future routine employee screening 

using Tubersol® brand tuberculin or other FDA-approved tests 

such as QuantiFERON®-TB Gold. 

Health Hazard Evaluation Report 2007-0012-3046 Page  
Results And disCussion 

(Continued) NIOSH investigators evaluated the fire department’s occupational 

health and medical screening program at the local hospital. 

All prior TST records were reviewed for the 104 firefighters in 

the department. This hospital had provided medical screening 

services for the department for approximately 8 years. We 

reviewed past TST records and found no consistent TST program. 

Prior to 2005, testing involved only a few firefighters per year 

and two-step TST was not employed in accordance with CDC 

recommendations [CDC 2005c]. In 2005, at the recommendation 

of the occupational medicine staff at the hospital, the department 

decided to implement tuberculosis screening following the NFPA 

“Standard on Comprehensive Occupational Medical Programs 

for Fire Departments” also known as NFPA 1582 [NFPA 2007]. 

This document recommends tuberculosis screening annually or 

more frequently, according to CDC guidelines. Two-step TSTs 

were implemented for 33 firefighters on B shift; three were positive 

according to the State of Mississippi guidelines, which use ≥ 10 

mm induration at the upper cut-off level for most populations. 

These individuals were evaluated for active disease and prophylactic 

therapy. In 2006, 101 eligible firefighters were tested, with twostep TST administered to A and C shifts. An additional nine 

firefighters were identified with induration ≥ 10 mm and medically 

evaluated by District 6 Tuberculosis Program personnel. 

The record review and interviews with hospital staff found several 

discrepancies with program administration, when compared 

to current CDC recommendations [CDC 2005b]. These are 

summarized below: 

● Two-step testing was not administered in accordance with 

CDC guidelines, which require interpreting TST results 48–72 

hours after test placement. Results were not read for the 

first TST for up 3 weeks after placement in some individuals 

due in part to poor compliance in keeping appointments. 

Another contributing factor was the 2005 State of Mississippi 

Tuberculosis Skin Testing Certification course materials, which 

allow for an alternate schedule of reading the first TST one 

week after placement, then immediately placing the second 

TST with interpretation of results of this second test in 48–72 

hours [Mississippi 2005]. In October 2006, conversations with 

State of Mississippi public health officials clarified that this 

alternate schedule is intended primarily for nursing homes 

and home health care where costs are a concern and was not 

Page  Health Hazard Evaluation Report 2007-0012-3046 
Results And disCussion 

(Continued) intended to be utilized for routine TST screening programs 

for populations such as healthcare workers or firefighters 

[Quilter 2006]. This is not stated in the course materials and 

should be clarified to avoid confusion. Given the long delay in 

interpretation of the first TST results, it is not known whether 

individuals who subsequently test positive on a second TST 2-3 

weeks later have recent exposure, or a “boosted” response. 

● TST induration was read along the vertical axis of the forearm, 

instead of along the horizontal axis, as recommended in CDC 

guidance [CDC 2005b]. Consistently reading TST along the 

horizontal axis improves standardization of results from one test 

interpreter to the next. 

● Compliance with follow-up appointments was an issue among 

firefighters, and is a common problem in TST screening 

programs. Missed appointments result in increased costs for the 

hospital and fire department, and lead to the administration of 

multiple TSTs, which may sensitize the patient to the purified 

protein in the test and cause false- positive results over time. 

● Two PPD preparations are available in the United States: 

Tubersol® (Connaught Laboratories Limited, Toronto, 

Canada) [Connaught Laboratory 2007] and APLISOL® 

(Parkdale Pharmaceuticals, Rochester, Michigan) [Parkdale 

Pharmaceuticals 2004]. The hospital had traditionally used 

Tubersol®, and in February 2006 purchasing agents in the 

hospital pharmacy switched to APLISOL® without informing 

the staff who administered the TSTs. CDC guidelines 

recommend that TB screening programs should use one 

antigen consistently and should realize that changes in products 

might make serial changes in TST results difficult to interpret. 

In one report, changes in product use resulted in a cluster 

of pseudoconversions erroneously indicated as a healthcareassociated outbreak [Blumberg 2000]. 

ConClusions Based on our investigation, we concluded that none of the 12 

firefighters had LTBI, and their initial TSTs were false-positives. 

Discrepancies in the contract hospital’s TST program and changes 

in brand of tuberculin used led to these false-positive results. 

Health Hazard Evaluation Report 2007-0012-3046 Page  
ReCommendAtions

The Meridian Fire Department has two options concerning future 

tuberculosis screening for its firefighters. The advantages and 

disadvantages of both approaches are outlined here. 

Option One: Continue Annual Tuberculosis Screening. 

● In order to comply with NFPA 1582 “Standard on 

Comprehensive Occupational Medical Programs for Fire 

Departments,” the Meridian Fire Department could continue 

with annual firefighter tuberculosis screening. This includes 

baseline tuberculosis screening at the time of employment 

(either two-step TST using Tubersol® or QuantiFERON®-

TB Gold when available) and TST every 12 months for all 

firefighters. Advantages of this approach include a higher 

likelihood of identifying a firefighter with LTBI or active 

tuberculosis earlier in the course of their infection so they can 

be medically evaluated. Another advantage is this option is 

easier to implement and maintain, because fire department 

management does not have to conduct an annual TB risk 

assessment to determine testing frequency as outlined in option 

two below. Disadvantages include the greater potential for 

false-positive TST results, unnecessary drug therapy for LTBI 

for firefighters, and increased cost to the department in fees for 

tuberculosis screening and missed duty time for test placement 

and interpretation. 

Option Two: Conduct Annual TB Risk Assessment for 

Department Firefighters to Determine Testing Frequency. 

● Based on current CDC guidelines and the TB risk assessment 

we conducted during our site visit, the Meridian Fire 

Department at this time is classified as low risk for TB 

transmission. For EMS workers classified as low risk, CDC 

recommends baseline tuberculosis screening at the time 

of employment (either two-step TST using Tubersol® or 

QuantiFERON®-TB Gold when available) and deferring 

annual firefighter TST unless the risk assessment profile 

changes or a known exposure occurs. If this approach is 

adopted, fire department management should conduct its own 

annual tuberculosis risk assessment. This would necessitate 

close communication with State of Mississippi District 6 

Tuberculosis Program personnel to monitor the incidence of 

tuberculosis in the community. If job duties changed, such as 

Page  Health Hazard Evaluation Report 2007-0012-3046 
ReCommendAtions 

(Continued) implementation of ambulance transport by the department 

or an increase in the number of EMS calls to higher-risk 

populations such as migrant workers or prisons, the program 

would need to be re-evaluated. An advantage of this option is 

less potential for false-positive test results among firefighters, 

because fewer TSTs will be performed. This in turn will lessen 

the potential for firefighters to be placed on drug therapy for 

LTBI, and will result in lower occupational medical surveillance 

costs for the department. Disadvantages include a greater 

possibility of not identifying a firefighter who has been exposed 

to TB, either occupationally or during off-duty activities, in 

a timely manner. Potential consequences could include the 

development of contagious tuberculosis disease in a firefighter 

and potential transmission to coworkers and others. 

Regardless of which option is adopted, any tuberculosis testing 

that occurs should follow CDC guidelines and recommendations. 

This includes, but is not limited to: (1) administering two-step 

TST to trainees and/or new hires upon employment, or using 

QuantiFERON®-TB Gold if available; (2) following established 

CDC procedures for test administration, administration, and 

record-keeping; and (3) considering using QuantiFERON®-TB 

Gold when available due to its advantages previously discussed. 

CDC guidelines state that using QuantiFERON®-TB Gold is 

appropriate in all situations where TST has traditionally been used, 

including employee screening programs. 

Fire Department management and union leadership should 

continue to emphasize the importance of compliance with all 

medical examinations, tests, and appointments. Such compliance 

allows the timely recognition of medical problems if they exist, 

and reduces operating costs for the Department from missed 

examinations and repeat testing. Additionally, the Department 

should continue periodic refresher training on tuberculosis and 

bloodborne pathogens for firefighters. This includes training on 

the early recognition of patients with potentially communicable 

diseases such as tuberculosis, so personal protection measures 

can be implemented on EMS calls. Exposures may be limited by 

having EMS workers using an N95 respirator or placing a surgical 

mask on the patient if medically feasible. 

Fire Department management should incorporate N95 respirator 

training and fit-testing into their worksite-specific respiratory 

protection program, in accordance with OSHA Standard 1910.134 

[29 CFR 1910.134]. 

Health Hazard Evaluation Report 2007-0012-3046 Page  
RefeRenCes 

Blumberg H, White N, Parrott P, Gordon W, Hunter M, Ray S 

[2000]. False-positive tuberculin skin test results among health care 

workers. JAMA 283(21):2793. 

CDC [2005a]. Guidelines for Using the QuantiFERON-TB Gold 

Test for Detecting Mycobacterium tuberculosis Infection. MMWR 

54(15):49–55. 

CDC [2005b]. Guide for primary health care providers: targeted 

tuberculin testing and treatment of latent tuberculosis infection. 

Atlanta, GA: Department of Health and Human Services, U.S. 

Public Health Service, Centers for Disease Control and Prevention. 

CDC [2005]. Guidelines for preventing the transmission of 

Mycobacterium tuberculosis in health-care Settings. Atlanta, GA: 

Department of Health and Human Services, U.S. Public Health 

Service, Centers for Disease Control and Prevention. 

CFR. Code of Federal Regulations. Washington DC: U.S. 

Government Printing Office, Office of the Federal Register. 

Cellestis Corporation [2007]. QuantiFERON-TB Gold Package 

Insert. [http://www.cellestis.com/ IRM/Content/gold/Gold_ 

USAPackageInsert.pdf]. Date accessed: February 2007. 

Connaught Laboratories Limited [2007]. Tuberculin purified 

protein derivative (Mantoux) Tubersol® diagnostic antigen. 1755 

Steeles Avenue West, Toronto, Ontario, Canada, M2R 3T4. 

Mississippi State Department of Health [2005]. Tuberculosis 

Update and Skin Test Certification Course Notes. Jackson, MS. 

NFPA [2007]. NFPA 1582: Standard on comprehensive 

occupational medical program for fire departments. Quincy MA: 

National Fire Protection Association. 

OSHA [2006]. Respiratory Protection Standard. [http:// 

www.osha.gov/pls/oshaweb/owadisp. show_document?p_ 

table=STANDARDS&p_id=12716]. Date accessed: February 2007. 

Parkdale Pharmaceuticals [2004]. APLISOL® (Tuberculin purified 

protein derivative, diluted [stabilized solution]). Diagnostic 

antigen for intradermal injection only. Rochester, MI: Parkdale 

Pharmaceuticals. 

Page  Health Hazard Evaluation Report 2007-0012-3046 
RefeRenCes (Continued) 

Quilter S [2006]. Telephone conversation on November 21, 2006, 

between S. Quilter, Mississippi State Department of Health, and 

J. Gibbins, Division of Surveillance, Health Evaluations and Field 

Studies, National Institute for Occupational Safety and Health, 

Centers for Disease Control and Prevention, Public Health 

Service, U.S. Department of Health and Human Services. 

Health Hazard Evaluation Report 2007-0012-3046 Page  
Appendix: evAluAtion CRiteRiA 

TB Infection 

Tuberculosis is caused by infection with the bacteria Mycobacterium tuberculosis. Initial infection usually 

goes unnoticed, with no clinical signs or symptoms. Ninety percent of people with this form of infection, 

also known as latent tuberculosis infection or LTBI, never develop active disease. People with LTBI are 

not infectious to other people. However, approximately 10% of people with LTBI will develop tuberculosis 

disease months to years after initial infection. Tuberculosis disease is characterized by clinical symptoms 

such as fever, fatigue weight loss, and night sweats. People with tuberculosis disease can be infectious to 

others. 

Tuberculin Skin Testing 

The goal of TST is to identify people with LTBI for drug therapy or surveillance, before they have the 

potential to develop tuberculosis disease. TST has historically been used to evaluate the close personal 

contacts of people with contagious TB (contact investigation), screening of higher-risk groups such as 

foreign-born immigrants, prisoners, or people with immunosuppression, and groups with higher potential 

for close exposure to potentially contagious TB cases such as healthcare workers and firefighters. However, 

patients can have false-positive TST reactions for many reasons, including infection with nontuberculous 

mycobacteria, previous BCG vaccination, incorrect TST administration and/or test interpretation, 

and sensitization from prior TST. False-positive TST are more likely to occur in populations where 

the incidence of tuberculosis is low; therefore, CDC guidelines recommend TST administration for 

occupational exposure be based on a facility risk assessment. These guidelines can be found in “Guidelines 

for Preventing the Transmission of Mycobacterium tuberculosis in Health-Care Setting, 2005” [CDC 

2005]. 

NFPA Guidelines 

The NFPA 1582 “Standard on Comprehensive Occupational Medical Programs for Fire Departments” 

mandates annual firefighter TB screening [NFPA 2007]. NFPA considers firefighters, especially those 

performing EMS response and patient transport, are at increased risk for tuberculosis exposure and 

potential infection when compared to the general population. NFPA Standards are consensus-based 

guidelines that are intended to provide guidance and recommendations; NFPA has no legal authority to 

enforce compliance with any NFPA codes, standards, recommendations, or guides that it publishes [NFPA 

2007]. 

QuantiFERON®-TB Gold 

An alternative to TST, QuantiFERON®-TB Gold was approved by the FDA in 2005, and is manufactured 

and marketed by Cellestis. It is an enzyme-linked immunosorbent assay that is more specific for the 

diagnosis of tuberculosis than TST. This means that QuantiFERON®-TB Gold will have fewer falsepositive reactions when compared to TST, especially in populations with a low incidence of tuberculosis. 

Advantages of QuantiFERON®-TB Gold include: (1) the test is not affected by prior BCG vaccination; 

(2) it excludes most, but not all non-TB mycobacteria species; (3) results can be available in 24 hours; (4) it 

requires a single patient visit to draw blood, improving patient compliance, especially if blood is already 

Page 0 Health Hazard Evaluation Report 2007-0012-3046 
Appendix: evAluAtion CRiteRiA (Continued) 

being collected for other required medical tests as part of an occupational health surveillance program; (5) 

two-step testing is not necessary–booster effect does not occur; (6) it does not boost responses measured by 

subsequent testing; and (7) it avoids potential errors in interpretation seen with TST. 

These advantages mean that fewer false-positive results should be seen when QuantiFERON®-TB Gold is 

used, as compared to TST. This will save on medical costs from evaluating patients for active tuberculosis 

infection (interviews, chest x-rays, blood work) drug costs for the treatment of LTBI, and missed work for 

medical follow-up appointments. More importantly, fewer false-positive results help avoid the psychological 

effects and worry about being infected with tuberculosis. 

Some disadvantages of QuantiFERON®-TB Gold are: (1) blood samples, once collected, must be 

processed by a qualified laboratory within 12 hours; (2) because the test is relatively new, laboratory 

availability is limited in some parts of the country; (3) the test is sensitive to the type of blood collection 

used; (4) in general, cost of the test itself is higher than TST, however, this cost is likely offset by the fact 

that only one visit is required, which results in less missed work; and (5) data is limited in children under 

17 and in immunosuppressed populations. 

Additional disadvantages, also seen with TST, include: (1) does not differentiate between LTBI and active 

disease; (2) negative results do not exclude Mycobacterium tuberculosis infection (false-negative reactions); 

(3) medical evaluation is still needed if test is negative but the patient has signs or symptoms suggestive of 

tuberculosis infection; and (4) sensitivity is likely less in immunocompromised patients. 

References 

CDC [2005]. Guidelines for preventing the transmission of Mycobacterium tuberculosis in health-care 

Settings. Atlanta, GA: Department of Health and Human Services, U.S. Public Health Service, Centers 

for Disease Control and Prevention. 

NFPA [2007]. NFPA 1582: Standard on comprehensive occupational medical program for fire 

departments. Quincy MA: National Fire Protection Association. 

Health Hazard Evaluation Report 2007-0012-3046 Page  
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Page  Health Hazard Evaluation Report 2007-0012-3046 
ACknowledgements 

And AvAilAbility of 

RepoRt The Hazard Evaluation and Technical Assistance Branch (HETAB) 

of the National Institute for Occupational Safety and Health 

(NIOSH) conducts field investigations of possible health hazards 

in the workplace. These investigations are conducted under the 

authority of Section 20(a)(6) of the Occupational Safety and 

Health (OSHA) Act of 1970, 29 U.S.C. 669(a)(6) which authorizes 

the Secretary of Health and Human Services, following a written 

request from any employers or authorized representative of 

employees, to determine whether any substance normally found 

in the place of employment has potentially toxic effects in such 

concentrations as used or found. 

HETAB also provides, upon request, technical and consultative 

assistance to federal, state, and local agencies; labor; industry; and 

other groups or individuals to control occupational health hazards 

and to prevent related trauma and disease. Mention of company 

names or products does not constitute endorsement by NIOSH. 

This report was prepared by John Gibbins and Elena Page of 

HETAB, Division of Surveillance, Hazard Evaluations and Field 

Studies (DSHEFS). Medical field assistance was provided by 

Barbara MacKenzie, Division of Applied Research and Technology. 

Analytical support was provided by Memphis Pathology Laboratory. 

Desktop publishing was performed by Robin Smith and Donna 

Pfirman. Editorial assistance was provided by Ellen Galloway. 

Copies of this report have been sent to employee and management 

representatives at the Meridian Fire Department; and the OSHA 

Regional Office. This report is not copyrighted and may be freely 

reproduced. The report may be viewed and printed from the 

following internet address: http://www.cdc.gov/niosh/hhe. Copies 

may be purchased from the National Technical Information Service 

(NTIS) at 5825 Port Royal Road, Springfield, Virginia 22161. 

For the purpose of informing affected employees, copies of this 

report shall be posted by the employer in a prominent place 

accessible to the employees for a period of 30 calendar days. 

Health Hazard Evaluation Report 2007-0012-3046 Page  
Recommended Citation: NIOSH [2007]. Health Hazard Evaluation Report: 

City of Meridian Fire Department, Meridian, Mississippi. Cincinnati, OH: U.S. 

Department of Health and Human Services, Public Health Service, Centers for 

Disease Control and Prevention, National Institute for Occupational Safety and 

occupational safety and health topics contact NIOSH at: 

1-800-35-NIOSH (1-800-356-4674) 

Fax: 1-513-533-8573 

E-mail: pubstaft@cdc.gov 

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Safety and health at work for all people 

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 National Institute for Occupational 

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Evaluation of Tuberculin Skin Test Conversions at a Mississippi Fire Department, 

Health, NIOSH HETA No. 2007-0012-3046. 

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