Test Conversion Rates Research Articles

A university hospital's 10-year experience with tuberculin testing: Value of the 2-step tuberculin skin test

The usefulness of the 2-step tuberculin skin test as a tool for monitoring tuberculosis exposure among health care workers is controversial. We aimed to determine the cost-effectiveness and influence of initiation of a preemployment, 2-step tuberculin skin-testing program on the annual tuberculin skin conversion rate among a university hospital's health care workers. The tuberculin skin test conversion rates among the recipients of 31,729 tuberculin skin tests over 10 years were retrospectively analyzed. Data from the first 6 years of this study were generated when a single preemployment tuberculin skin test was utilized. Data from the last 4 years were gathered after the advent of a preemployment 2-step program. A cost analysis of the 2-step tuberculin skin test process was performed to determine the annual cost of this program. Relative risk of a conversion was 8.43 times less during the 2-step period when compared with the years when a single tuberculin skin test was given at the start of employment (P < .001). A cost analysis showed that the annual added cost of the 2-step program was approximately 9,565 US dollars. A greater than 8-fold reduction in the number of annual tuberculin skin test conversion coincided with, but could not be attributed solely to, the initiation of a 2-step program in our hospital. The Infection Control Committee concluded that the 2-step testing program is essential to achieve the hospital's goal of a 0% annual tuberculin skin test conversion rate and that the annual cost is justified.

Tuberculin skin test conversion and reactivity rates among adults with and without human immunodeficiency virus in urban settings in Ethiopia.

To investigate whether low CD4+ T-cell counts in healthy and human immunodeficiency virus (HIV)-infected Ethiopians influence tuberculosis (TB) immunological memory, tuberculin skin test (TST) conversion and reactivity rates were investigated among adults with and without HIV infection in urban settings in Ethiopia. Reaction to the TST was analyzed with purified protein derivative by the Mantoux technique. A total of 1,286 individuals with TST results of > or = 5-mm (n = 851) and < or = 4-mm (n = 435) induration diameters were included. Individuals with < or = 4-mm induration sizes were followed up for 21.4 +/- 9.5 months (mean +/- standard deviation) to observe skin test conversion. The overall TST reactivity (> or = 5-mm induration diameter) was 66.2% (n = 851). Reactivity was significantly lower among HIV-positive persons (40.5%) than among HIV-negative persons (68.7%) (P < 0.001). Of the above persons, 32 incident TB patients were checked for their TST status 13.05 +/- 11.1 months before diagnosis and reactivity was found among 22 (68.7%) of them. Of the TST-negative persons with 0- to 4-mm indurations who were followed up for 3 years, the conversion rate to positivity was 17.9/100 person-years of observation (PYO) (14.4/100 PYO and 18.3/100 PYO in HIV-positive and -negative persons, respectively). Despite lower absolute CD4+ T-cell numbers in Ethiopians, higher TST conversion and reactivity rates show the presence of a higher rate of latent TB infection and/or transmission. The lower TST positivity rate before a diagnosis of TB disease showed the lower sensitivity of the test. This indicates the need for other sensitive and specific diagnostic and screening methods to detect TB infection, particularly among HIV-positive persons, so that they can be given prophylactic isoniazid therapy.

Exposure-effect relationship of platinum salt allergy in a catalyst production plant: Conclusions from a 5-year prospective cohort study

Background: There is a high incidence of occupational asthma and rhinitis caused by platinum (Pt) salts in precious-metal refineries. Objective: We sought to assess exposure to Pt salts and the incidence of Pt salt allergy in a catalyst production plant. Methods: A 5-year prospective cohort study was performed in 159 catalyst production workers (94.6% of recruited), 50 craftsmen (92.6% of recruited), and 66 control subjects (76.7% of recruited) at yearly intervals. Subjects were assigned to exposure categories of high levels of Pt (n = 115), persistently low levels of Pt (n = 51), intermittently low levels of Pt (n = 61), or no Pt (n = 48) after the initial survey according to job title and job location. Skin prick test conversion from a negative response to a 4 mm or larger wheal response with a 10–2 mol/L hexachloroplatinic acid solution was chosen as the outcome variable. Results: Exposure assessment of airborne Pt and Pt in the serum of workers demonstrated clear differences between exposure categories. The threshold limit value of 2 μg/m3 for soluble Pt was exceeded in 3 (4%) of 78 measurements. Thirteen subjects assigned to high exposure showed skin test conversion, and new allergic symptoms were associated with exposure. Among the high-exposure category, the incidence rate of skin prick test conversion was 5.9 per 100 person-years for newly employed subjects (n = 79) and 2.1 per 100 person-years for those who had already been employed at the time of the initial survey (n = 36). A predicting factor for skin test conversion in highly exposed subjects was smoking status (relative risk, 3.9; 95% confidence interval, 1.6-9.7) but not atopy or bronchial hyperresponsiveness. Conclusion: Sensitization to Pt salts may develop in workers of catalyst production plants. Both the exposure to Pt salts and the incidence of Pt salt allergy were lower compared with reported data from precious-metal refineries. (J Allergy Clin Immunol 2000;105:364-70.)

StaffTRAK-TB: software for surveillance of tuberculosis infection in healthcare workers.

The Centers for Disease Control and Prevention (CDC) recommends periodic tuberculin skin testing of healthcare workers with potential exposure to Mycobacterium tuberculosis. However, many healthcare facilities have neither a system to identify workers due for their skin test nor a means of analyzing aggregate data. To illustrate some of the complexities involved in tuberculin skin test (TST) tracking and analysis, and how these might be addressed, this report describes a software package called staffTRAK-TB, developed by the CDC to facilitate surveillance of tuberculosis infection in healthcare workers. staffTRAK-TB records data for each healthcare worker, including demographic information, occupation, work location, multiple TST results, and results of evaluations to determine if clinically active tuberculosis is present. Programmed reports include lists of workers due and overdue for skin tests, and skin test conversion rates by occupation or worksite. Standardization of types of occupations and locations allows data from multiple facilities to be aggregated and compared. Data transfer to the CDC can be performed via floppy diskettes. staffTRAK-TB illustrates important issues in software structure, standardization of occupation and work-location information, relevant data items, and reports and analyses that would be useful in practice. Developing software that adequately addresses the epidemiological issues is complex, and the lessons learned may serve as a model for hospital epidemiologists, infection control personnel, occupational health personnel, and computer programmers considering software development in this area or trying to optimize their facility's TST surveillance.

Tuberculin skin test conversion rate in dental health care workers—results of a prospective study

Objectives: The tuberculin skin test conversion rate over 12 months in dentists, dental hygienists, and dental assistants was assessed in 3 US-Mexico border counties of Texas in which reported tuberculosis rates were high compared with the rates for Texas and the United States. Methods: Tuberculin skin tests were administered to 284 subjects and repeated on nonreactors 12 months later. Participants also completed self-administered questionnaires. Results: The baseline positive tuberculin skin test prevalence was 4.6%. Nonreactors were more likely to have been born in the United States ( P < .001). The tuberculin skin test conversion rate over 12 months was 1.7%. Conclusion: Results indicate a need for heightened awareness of tuberculosis transmission and annual surveillance by dental health care workers, as recommended by the Centers for Disease Control and Prevention. (AJIC Am J Infect Control 1999;27:385-7)

Tuberculin Test Conversion among Employees of a Tertiary Care Hospital in Riyadh, Saudi Arabia

The objective of this study was to determine the tuberculin skin test conversion rate, as well as the course and outcome of the converters, among employees of a tertiary care hospital. The study is a retrospective, cohort descriptive study undertaken at the King Faisal Specialist Hospital and Research Centre, in Riyadh, Saudi Arabia. The study was undertaken over a four-year period from 1993 to 1996, and the subjects were employees who had annual screening PPD skin tests. The outcome measures skin test conversion, prophylactic treatment with isoniazid (INH), side effects, and development of clinical tuberculosis. A total of 6883 tuberculin skin tests were performed during the study period. The mean annual conversion rate was 1.55%. About 78% of the converters received INH prophylaxis, but only 75% of those who started chemoprophylaxis completed the course. The side effects of INH treatment were found in 23% of those on treatment, and one of the converters developed clinically active tuberculosis during the study period. At the King Faisal Specialist Hospital and Research Centre, the mean annual tuberculin skin test conversion rate among employees is similar to that found in other studies, but compliance to oral isoniazide prophylaxis is low. There is a need to develop strategies to improve compliance.

Tuberculin Skin Test Conversion Rates in New York City Emergency Medical Service Health Care Workers

Objective: To determine annual tuberculin skin test conversion (infection) rates for prehospital health care workers (EMTs and paramedics) in an urban environment with a high prevalence of Mycobacterium tuberculosis Methods: We conducted a prospective study of prehospital health care workers for the New York City EMS, EMS Employee Health Service, and the Fire Department Bureau of Health Service to determine the tuberculin skin test conversion rates. In 1992, all current and new EMS prehospital health care workers without a known history of a positive tuberculin reaction received a baseline tuberculin purified protein derivative (PPD) skin test. Thereafter, (January 1, 1993–December 31, 1996) all EMS health care workers who had negative PPD skin test results received annual tuberculin PPD skin tests. Tuberculin skin test conversion was defined as induration of 10 mm or greater in a worker with a documented prior negative test result. The PPD skin test reaction was measured by trained professional readers. Results: A total of 7,290 PPD test results were read during this study. Compliance with annual testing was 75%. Annual tuberculin skin test conversion rates were 1.3% in 1993, .7% in 1994, .1% in 1995, and .2% in 1996 (average .5%). In a static subgroup with at least 15 years’ seniority, compliance with annual testing was 100% and annual tuberculin skin test conversion rates were .5% in 1993, 0 in 1994, .5% in 1995, and 1.5% in 1996 (average .6%). Conclusion: Despite the high prevalence of M tuberculosis infection in New York City and the potential for difficulty in the use of respiratory precautions during emergency response operations, EMS prehospital health care workers have an annual tuberculin conversion rate that is relatively low compared with hospital-based health care workers. [Prezant DJ, Kelly KJ, Mineo FP, Janus D, Karwa ML, Futterman N, Nolte C: Tuberculin skin test conversion rates in New York City emergency medical service health care workers. Ann Emerg Med August 1998;32:208-213.]

Comparison of Tuberculosis Infection Control Programs in Canadian Hospitals Categorized by Size and Risk of Exposure to Tuberculosis Patients, 1989 to 1993 – Part 2

To analyze tuberculosis (TB) programs in acute care hospitals (hospitals) categorized by size and risk of exposure to TB patients from 1989 to 1993. Retrospective survey. Members of the Community and Hospital Infection Control Association-Canada and l'Association des professionnels pour la prévention des infections who worked in Canadian hospitals received questionnaires. One questionnaire per hospital was completed. Hospitals reported the number of respiratory TB and human immunodeficiency virus (HIV) cases admitted, the engineering and environmental controls available, and the type of occupational TB screening programs available. Data were stratified by hospital size and risk of exposure to TB patients. Thirty-four (10.9%) hospitals with at least 500 beds admitted more than 50% of the TB cases, more than 40% of the multidrug-resistant TB (MDR-TB) cases and more than 65% of the HIV cases. Thirty-six (11.6%) facilities classified as high risk hospitals reported more than 70% of the TB cases, more than 58% of the MDR-TB cases and more than 75% of the HIV cases. A significantly higher pooled average tuberculin test conversion rate was found in individuals working in high risk (4.4%) than in low risk hospitals (1.5%). Significantly more high risk than low risk hospitals had an isolation room with air exhausted outside, negative air pressure and at least six air changes per hour. Only 13 high risk hospitals had all three engineering characteristics. Surgical masks were used for respiratory protection in 18 (50%) high risk and 186 (77.8%) low risk hospitals. Nosocomial transmission of Mycobacterium tuberculosis may have occurred because TB programs available in many Canadian hospitals were inadequate.

Tuberculosis and HIV infection among female inmates in São Paulo, Brazil: a prospective cohort study.

Prison populations are at increased risk of both human immunodeficiency virus (HIV) and Mycobacterium tuberculosis infections, but among female inmates information on such risks remains scarce, especially in developing countries. Between October 1992 and November 1993, 350 women incarcerated at a prison in São Paulo, Brazil, were prospectively evaluated for HIV and M. tuberculosis infection and disease. Among them, 87 (25%) were HIV seropositive, and 20 (5.7%) had tuberculosis (TB). During the incarceration period, the purified protein derivative test conversion rate was 29% for HIV-positive and 32% for HIV-negative women. However, the incidence of TB was 9.9 per 100 person-years for HIV-positive and 0.7 per 100 person-years of incarceration for HIV-negative women (p < 0.0001). A multivariate analysis indicated that HIV infection (p < 0.0001) and incarceration time < 12 months (p < 0.05) were each associated with TB. These findings indicate that new transmissions of M. tuberculosis infection are common among female inmates and that HIV-infected women are more likely to acquire active disease during the first 12 months of incarceration. Because of their role in childbearing and care female inmates are an important potential source of transmission of M. tuberculosis, and new strategies to control the spread of TB in prisons need to be developed.

Dramatic decrease in tuberculin skin test conversion rate among employees at a hospital in New York City

Background: The Centers for Disease Control and Prevention recently issued updated guidelines for preventing the transmission of tuberculosis in health care facilities. Many recommendations, including the use of high-efficiency particulate air filter respirators, are expensive to implement and of unproven efficacy. We therefore reviewed the tuberculin skin test conversion rate among our employees from 1991 to 1993, before introduction of high-efficiency particulate air filter respirators. During this period, several other improvements in tuberculosis control were implemented. Methods: Employee tuberculin test conversion rates were reviewed by 6-month interval from 1991 to 1993. Results: Throughout the study period, several tuberculosis control measures were implemented, including early isolation of patients with suspected cases of tuberculosis in rooms with negative-pressure ventilation, placement of germicidal UV light fixtures into patient rooms and common areas, and use of Technol shields (Technol, Inc., Fort Worth, Texas) (1991), particulate respirators (1992), and dust-mist-fume respirators (1993). With these improvements, the conversion rate among employees fell from 20.7% in the first 6 months of 1991 to 5.8% in the latter half of 1993. Conclusions: The rate of skin test conversion among our employees decreased before introduction of high-efficiency particulate air filter respirators. This suggests that nosocomial spread of tuberculosis can be decreased by means of previously established, less costly methods.

Preventing the nosocomial transmission of tuberculosis.

To study the efficacy of expanded tuberculosis infection control measures consisting primarily of administrative controls. Descriptive case series. University-affiliated, inner-city hospital. Introduction of expanded tuberculosis infection control measures (including an expanded respiratory isolation policy). The number of tuberculosis exposure episodes and skin test conversion rates of health care workers were measured before and after implementation of expanded infection control measures. Tuberculosis exposure episodes (the number of patients who were not placed in respiratory isolation at admission but who subsequently had a diagnosis of acid-fast bacilli smear-positive pulmonary tuberculosis during that admission or within 2 weeks of discharge) were compared for two time periods: the 8 months before and the 28 months after implementation of infection control measures. Tuberculin skin test conversion rates among health care workers were evaluated during a 2.5-year period. After expanded infection control measures were implemented, the number of tuberculosis exposure episodes decreased from 4.4 per month (35 episodes among 103 patient admissions for potentially infectious tuberculosis over 8 months) to 0.6 per month (18 episodes among 358 patient admissions for smear-positive pulmonary tuberculosis over 28 months) (odds ratio, 9.72; 95% CI, 4.99 to 19.25 [P < 0.001]). The cumulative number of days per month that potentially infectious patients with tuberculosis were not in isolation decreased from 35.4 to 3.3 (P < 0.001). A concomitant decrease in tuberculin skin test conversion rates in health care workers was seen; 6-month tuberculin skin test conversion rates decreased steadily from 3.3% (118 conversions in 3579 health care workers; 1/92 to 6/92), 1.7%, 1.4%, 0.6%, to 0.4% (23 conversions in 5153 workers [1/94 to 6/94]) (P < 0.001). Infection control measures effectively prevented nosocomial transmission of tuberculosis to health care workers. Administrative controls appear to be the most important component of a tuberculosis infection control program and should be the first focus of such a program, especially at public hospitals, where resources are most likely to be limited.

Efficacy of control measures in preventing nosocomial transmission of multidrug-resistant tuberculosis to patients and health care workers.

To assess the efficacy of control measures in decreasing nosocomial transmission of multidrug-resistant tuberculosis. Retrospective cohort study. A teaching hospital in New York City. 40 patients hospitalized with multidrug-resistant tuberculosis (case-patients) and health care workers receiving tuberculin skin testing. Centers for Disease Control and Prevention (CDC) 1990 guidelines for preventing transmission of tuberculosis, including 1) prompt isolation and treatment of patients with tuberculosis; 2) rapid diagnostic techniques for processing Mycobacterium tuberculosis specimens; 3) negative-pressure isolation rooms; and 4) molded surgical masks for health care workers. Proportion of case-patients with nosocomially acquired tuberculosis and rate of tuberculin skin test conversion among health care workers before and after implementation of control measures. The proportion of patients with multidrug-resistant strains of M. tuberculosis decreased after the interventions (10 of 70 [14%] compared with 30 of 95 [32%] patients before the intervention; relative risk [RR], 0.5; 95% CI, 0.2 to 0.9). Before onset of multidrug-resistant tuberculosis, case-patients in the intervention period were as likely to be hospitalized on high-risk wards containing patients with tuberculosis (4 of 10 compared with 17 of 30 patients; RR, 0.7; P = 0.5) but were less likely to be exposed to another case-patient with tuberculosis (1 of 10 compared with 20 of 30 patients; RR, 0.2; P = 0.003). Tuberculin skin test conversion rates for health care workers assigned to wards housing patients with tuberculosis were lower in the intervention period than in the preintervention period (4 of 78 [5%] compared with 15 of 90 [17%] conversions; P = 0.02), decreasing to levels observed for workers assigned to other wards (4 of 78 [5%] compared with 9 of 228 [4%] conversions; P = 0.7). Implementing control measures reduced nosocomial transmission of multidrug-resistant strains to patients and health care workers.

The effect of the booster phenomenon on the tuberculin skin test conversion rate

The effect of the booster phenomenon on the tuberculin skin test conversion rate

Tuberculosis contact investigation: Two years of experience in New York City correctional facilities

Background: An increasing incidence of tuberculosis has been observed in the New York City correctional system. Methods: The diagnosis of active tuberculosis in persons within the correctional setting results in an investigation, with the identification and screening of contacts. Results: Thirty-four such investigations in the past 2 years in the New York City correctional system, where all inmates are screened for tuberculosis on admission, have resulted in an overall tuberculin skin test conversion rate of 6.74% in 1306 inmates. In 21 of these investigations the index had both smears and cultures positive for Mycobacterium tuberculosis and the conversion rate was 7.37% in 719 contacts tested. In seven investigations the index patient had a culture only positive for M. tuberculosis and the conversion rate was 6.58% in 243 inmates. In six investigations in which the index patients were subsequently found to have nontuberculous pneumonia or mycobacteria other than M. tuberculosis the conversion rate was 5.52% in 344 inmates. These rates are not statistically different. Conclusions: Whether the observed conversions in these events or in any of the contact investigations are due to intramural spread, anergy on admission, the booster phenomenon, or incubation of disease on admission is not known. The 5.5% conversion rate in those exposed to inmates confirmed not to have tuberculosis suggests the influence of booster phenomenon and consideration of two-step testing on admission.

Hospital outbreak of multidrug-resistant Mycobacterium tuberculosis infections. Factors in transmission to staff and HIV-infected patients.

To describe transmission of multidrug-resistant (MDR) Mycobacterium tuberculosis infection among patients and health care workers (HCWs) in a ward and clinic for human immunodeficiency virus (HIV)-infected patients in a hospital, four studies were conducted. Case patients and control patients were persons who had been treated in the HIV ward or clinic, whose clinical course was consistent with tuberculosis and who had at least one positive culture for M tuberculosis between January 1, 1988, and January 31, 1990, resistant to at least isoniazid and rifampin (case patients), or whose isolates were susceptible to all drugs tested (control patients). In the first study, case patients and control patients were compared to identify risk factors for MDR tuberculosis. In the second study, inpatient and outpatient days of MDR tuberculosis case patients were compared to determine whether acid-fast bacillus (AFB) smear-positivity or aerosolized pentamidine use was associated with higher numbers of subsequent MDR tuberculosis cases among exposed patients. In the third study, restriction fragment length polymorphism analysis was performed on available MDR and sensitive M tuberculosis isolates. In the fourth study, skin test conversion rates among HCWs in the HIV ward and clinic were compared with those of HCWs in another ward, and the strength of the associations between skin test conversions among HCWs on the HIV ward and the number of person-days that AFB smear-positive case patients and control patients were on this ward was estimated. Case patients were more likely than control patients to have been exposed on the HIV ward or clinic to an AFB smear-positive case patient (P less than .001). Inpatient and outpatient days of MDR tuberculosis case patients were associated with more subsequent cases of MDR tuberculosis if exposing case patients were smear-positive or if they received aerosolized pentamidine (P less than or equal to .01). Of 13 MDR isolates, all had one of two restriction fragment length polymorphism patterns; 10 sensitive isolates had restriction fragment length polymorphism patterns that were different from each other. The HCW skin test conversion rate was higher on the HIV ward and clinic than on the comparison ward (P less than .01). The risk of occupational acquisition of infection increased in direct proportion to the number of person-days that AFB smear-positive case patients were on the HIV ward (r = .75; P = .005), but did not increase in proportion to the number of person-days that AFB smear-positive control patients were there (r = -.36; P = NS). After isolation measures for AFB smear-positive tuberculosis patients were improved, MDR tuberculosis cases decreased to seven of 214 tuberculosis patients. Nosocomial transmission of MDR M tuberculosis infection to patients and HCWs occurred on the HIV ward and clinic. Infectiousness of MDR tuberculosis case patients was associated with AFB sputum-smear positivity. Case patients with MDR tuberculosis created a greater risk of skin test conversion for HCWs on the HIV ward than drug-susceptible control patients.

Nosocomial transmission of multidrug-resistant Mycobacterium tuberculosis. A risk to patients and health care workers.

To determine the factors associated with the development of multidrug-resistant tuberculosis among patients at a New York City Hospital and to investigate possible nosocomial transmission. A retrospective case-control study and tuberculin skin test survey. Twenty-three patients with tuberculosis whose isolates were resistant to at least isoniazid and rifampin (case patients) were compared with patients with tuberculosis whose isolates were susceptible to all agents tested (controls). Tuberculin skin test conversion rates were compared among health care workers assigned to wards where patients with tuberculosis were frequently or rarely admitted. A large, teaching hospital in New York City. Mycobacterium tuberculosis isolates from case patients and controls were typed by restriction fragment length polymorphism analysis. Case patients were younger (median age, 34 compared with 42 years; P = 0.006), more likely to be seropositive for HIV (21 of 23 compared with 11 of 23 patients; odds ratio, 11.5; 95% CI, 1.9 to 117), and more likely to have had a previous hospital admission within 7 months before the onset of tuberculosis (19 of 23 compared with 5 of 23 patients; odds ratio, 17.1; CI, 3.3 to 97), particularly on one ward (12 of 23 compared with 0 of 23 patients; odds ratio, undefined; P = 0.002). Health care workers assigned to wards housing case patients were more likely to have tuberculin skin test conversions than were health care workers assigned to other wards (11 of 32 compared with 1 of 47 health care workers; P less than 0.001). Few (6 of 23) case patients were placed in acid-fast bacilli isolation, and no rooms tested had negative pressure. Of 16 available multidrug-resistant isolates obtained from case patients, 14 had identical banding patterns by restriction fragment length polymorphism analysis. In contrast, M. tuberculosis isolates from controls with drug-susceptible tuberculosis had patterns distinct from each other and from those of case patients. These data suggest nosocomial transmission of multidrug-resistant tuberculosis occurred from patient to patient and from patient to health care worker and underscore the need for effective acid-fast bacilli isolation facilities and adherence to published infection control guidelines in health care institutions.

Tuberculosis screening in the long-term care setting.

Tuberculosis (TB) skin-testing practices in long-term care facilities (LTCFs) in North Carolina (NC) were assessed from a 56% (148/263) response to a comprehensive TB screening questionnaire. TB skin tests were administered to employees on initial employment by 98% and annually by 97% of the LTCFs, generally (74%) by the Mantoux method. Employee skin tests were read at the appropriate time interval of 48 to 72 hours by 91%, but less than half used diameter of induration when interpreting reactive tests. The booster test was performed on new employees at eight (6%) of the LTCFs. TB skin tests were routinely performed on newly admitted residents by 56% or conditionally required by 18%, generally (73%) by the Mantoux method. Resident skin tests were read at the appropriate time interval of 48 to 72 hours by 92%, but again only half correctly interpreted reactive tests as significant. Residents received routine annual skin tests at 71% of the LTCFs, generally (80%) by the Mantoux method. Eight (6%) facilities routinely performed the booster test on newly admitted residents. TB infection prevalence in new employees during 1983 was 8.1% (47/578) in seven LTCFs and in newly admitted residents was 6.4% (7/110) in three LTCFs supplying this data. The five-year mean TB skin test conversion rate among employees was 1.1% (101/9545) in 12 LTCFs and among residents was 0.9% (46/5216) in nine LTCFs supplying this data. Lack of compliance to established TB skin-testing guidelines in NC LTCF was prevalent. In recognition of described endemic and epidemic spread of TB in LTCFs, residents and employees of LTCFs should be screened for TB utilizing established skin-testing practices.