A statewide assessment of tuberculin skin testing of preschool children enrolled in medicaid managed care

OBJECTIVES

This study examined tuberculosis screening among preschool children enrolled in a statewide Medicaid managed care program.

METHODS

A random sample of 2,000 was selected from 19 to 35 month old children who were continuously enrolled in Rhode Island's Medicaid managed care program for 1 year. Sociodemographic data were obtained from computerized administrative databases. Medical record audits were performed to obtain the dates and results of tuberculosis tests.

RESULTS

Data from the medical record audits were available for 1,988 of the study children. For 1,215 of the study children (1,215/1,988 = 61%) a tuberculin skin test had been performed, but a reading was only documented for 736 children (60% of children who received a tuberculin skin test) and only one child tested positive (0.1%).

CONCLUSIONS

A majority of preschool children in this population in which the prevalence of risk factors for tuberculosis is likely to be relatively high did have a tuberculosis test performed. However, in many cases the tuberculin skin test was either not read or the results not documented. The low rate of positivity is consistent with current AAP guidelines for selective tuberculin skin testing.

Should medical students be routinely offered BCG vaccination?

BCG vaccination is no longer routinely offered to all medical students in Victoria. Practices in Australia's 15 medical schools vary widely with respect to BCG vaccination and surveillance for tuberculosis (TB) infection during the medical course. Health care workers can be exposed to TB in Australian hospitals, but the risk is much higher if they undertake work in countries with a high prevalence of TB, such as during student electives. BCG vaccination is safe, cheap and protects 50% or more of recipients from active TB, including multidrug-resistant TB. Protection is long-lasting, requires only a single dose, and there is new evidence that BCG may prevent primary infections, not just active disease. Although BCG vaccination interferes with the interpretation of the tuberculin skin test (TST), newer tests (QuantiFERON-TB Gold, T-SPOT.TB) are unaffected by BCG vaccination. We propose a standard approach for all Australian medical students that includes screening with TST and QuantiFERON-TB Gold/T-SPOT.TB at course entry, and recommending BCG vaccination for students who test negative, provided they have not previously received BCG vaccine.

Tuberculosis screening in migrants in selected European countries shows wide disparities

Well-established tuberculosis screening units in Western Europe were selectively sampled. Three screening units in Norway, two in the UK, one in the Netherlands and one in Switzerland were evaluated. The aim of this study was to describe a range of service models used at a number of individual tuberculosis units for the screening of new entrants into Europe. Semi-structured interviews were conducted with clinicians, nurses and administrators from a selected sample of European tuberculosis screening units. An outline of key themes to be addressed was forwarded to units ahead of scheduled interviews. Themes included the history of the unit, structure, processes and outputs involved in screening new entrants for tuberculosis. Considerable variation in screening services exists in the approaches studied. Units are sited in transit camps or as units within hospital facilities. Staff capacity and administration varies from one clinic per week with few dedicated staff to fully dedicated units. Only one site recorded symptoms; tuberculin testing was universal in children, but varied in adults; chest radiograph screening was universal except at one site where a positive tuberculin skin test or symptoms were required in those <35 yrs of age before ordering a radiograph. Few output data are routinely and systematically collected, which hinders comparison and determination of effectiveness and efficiency. Service models for screening new immigrants for tuberculosis appear to vary in Western Europe. The systematic collection of data would make international comparisons between units easier and help draw conclusions that might usefully inform service development.

Tuberculin skin testing in children

In 1996, the American Academy of Pediatrics (AAP) recommended targeted tuberculin skin testing (TST) of children while discouraging routine TST of children without risk factors for tuberculosis (TB). Recent studies have provided evidence in support of the targeted TST and recommendations that favor risk assessment over universal screening with TST. While evidence for targeted TB testing exists and benefits of screening programs are clear, administrative logistics could be a greater issue. The challenge for public health and school officials is to develop a screening program that avoids stigmatization of the at-risk group. Until then, pediatric healthcare providers will continue to have a key role in identifying children at risk for latent TB infection by using the AAP-endorsed risk-assessment questionnaire and should screen children with TST only when >1 risk factor is present.

Mixture analysis of tuberculin survey data from northern Malawi and critique of the method

SETTING

Various methods have been used to estimate the prevalence of Mycobacterium tuberculosis infection from tuberculin survey data. All are complicated by prior sensitisation to environmental mycobacteria and bacille Calmette-Guérin (BCG) vaccination. Mixture analysis has recently been proposed as a means of overcoming misclassification and improving infection prevalence estimates.

OBJECTIVE

To compare conventional and mixture model estimates of M. tuberculosis infection prevalence.

DESIGN

Mixture models with two or three univariate normal components were fitted to the results of 53 909 tuberculin tests conducted in northern Malawi during 1980-1984. Data were stratified by BCG status, sex and age and corrected for digit preference. Prevalence estimates derived from mixture models were compared with those of conventional methods.

RESULTS

The optimal model was age-dependent, with three- and one-component solutions preferred in younger and older age groups, respectively. In contrast with findings from elsewhere, a component corresponding to BCG vaccination was indistinguishable from that attributable to environmental mycobacterial exposure, and infection prevalence estimates in younger individuals with a BCG scar were inflated, irrespective of the method used.

CONCLUSION

The validity of infection prevalence and incidence estimates based on mixture modelling is probably locale-dependent, and the assumptions underlying mixture models may not realistically reflect underlying immunological processes.

Tuberculin reactivity among health care workers in nonhospital settings

BACKGROUND

We used workers' compensation data to identify health care workers at risk of tuberculosis exposure in the hospital and nonhospital environment.

METHODS

We identified State Fund workers' compensation claims having a documented tuberculin skin test (TST) conversion (size >or=10 mm) with a previous negative skin test between 1996 and 2000 in the State of Washington.

RESULTS

Health care workers experienced an overall accepted workers' compensation claim rate of 2.3 claims/10,000 full-time equivalent employees (FTEs) per year for tuberculin reactivity. Receptionists accounted for the largest number, with 18.4% tuberculin reactivity claims. The number of tuberculin reactivity claims was the highest for offices and clinics of doctors of medicine (3.7 per 10,000 FTEs), followed by medical laboratories (2.6 per 10,000 FTEs).

CONCLUSION

This study allowed characterization of employees in various nonhospital health services locations with higher number of tuberculin reactivity.

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

BACKGROUND

The usefulness of the 2-step tuberculin skin test as a tool for monitoring tuberculosis exposure among health care workers is controversial.

OBJECTIVES

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Clinical inquiries. How should we manage a patient with a positive PPD and prior BCG vaccination?

Prior bacille Calmette-Guerin (BCG) vaccination increases the likelihood of a positive tuberculosis (TB) 5TU purified protein derivative (PPD) skin test. The PPD response following BCG vaccine varies with age at vaccination, number of years since the BCG vaccination, number of times vaccinated, and number of PPDs performed. An induration of greater than 14 mm is unlikely to be due to prior BCG vaccination (strength of recommendation [SOR]: A, based on meta-analysis of validation cohort studies). The variable reaction after BCG vaccination, along with the desire to detect all cases of TB, has led to recommendations that all patients with a positive PPD test be treated as true positives. These patients should undergo chest radiography and appropriate treatment, regardless of history of BCG vaccine (SOR: B, extrapolation from level 1 study). A recently developed alternative is the interferon-gamma assay (QuantiFERON-TB Gold test), which may be used in place of, or in addition to, the PPD skin test for patients who are known to have received a BCG vaccine (SOR: B, extrapolation from a validation cohort study).

Tuberculin skin test among pulmonary sarcoidosis patients with and without tuberculosis: its utility for the screening of the two conditions in tuberculosis-endemic regions

BACKGROUND

Sarcoidosis is an increasingly important condition in developing countries, including those with a high prevalence of tuberculosis. The tuberculin skin test (TST) is one test used in distinguishing these two granulomatous conditions. It has been shown that a negative TST is highly sensitive for sarcoidosis. This retrospective study set out to assess the converse: the role of a positive test in the assessing the likelihood that a patient with sarcoidosis might also have tuberculosis.

METHODS

A retrospective chart review of 141 patients with biopsy-proved sarcoidosis, among whom there were 16 biopsy-proven sarcoidosis and tuberculosis patients and 125 sarcoidosis-only patients. The receiver operating curve was constructed by calculating the sensitivity and specificity of various levels of induration of the tuberculin skin test for the diagnosis of comorbid tuberculosis.

RESULTS

The area under the curve of the ROC did not differ from 0.5, meaning that the TST was not useful as a graded measure. This was largely due to its poor sensitivity. However, a level of greater than or equal to 10 mm induration, though insensitive, had a specificity of 97.6% for the diagnosis of tuberculosis among this population of sarcoidosis patients.

CONCLUSIONS

The tuberculin skin test in sarcoid patients has a high specificity but a poor sensitivity for tuberculosis. As such, while a negative TST in the general population is a sensitive test for sarcoidosis, a positive TST among sarcoidosis patients is a specific test for indicating tuberculosis. A positive TST in a patient suspected to suffer from sarcoidosis should therefore be an absolute indication for a thorough work-up for tuberculosis.

High rate of negative results of tuberculin and QuantiFERON tests among individuals with a history of positive skin test results

OBJECTIVES

To evaluate individuals at high risk for tuberculosis exposure who had a history of a positive tuberculin skin test (TST) result in order to determine the prevalence of unsuspected negative TST results. To confirm these findings with the QuantiFERON-TB test (QFT), an in vitro whole-blood assay that measures tuberculin-induced secretion of interferon-gamma.

METHODS

This survey was conducted from November 2001 through December 2003 at 3 sites where TST screening is regularly done. Detailed histories and reviews of medical records were performed. TSTs were placed and read by 2 experienced healthcare workers, and blood was drawn for QFT. Any subject with a negative result of an initial TST during the study (induration diameter, <10 mm) underwent a second TST and a second QFT. The TST-negative group comprised individuals for whom both TSTs had an induration diameter of <10 mm. The confirmed-negative group comprised individuals for whom both TSTs yielded no detectable induration and results of both QFTs were negative.

RESULTS

A total of 67 immunocompetent subjects with positive results of a previous TST were enrolled in the study. Of 56 subjects who completed the TST protocol, 25 (44.6%; 95% confidence interval [CI], 31.6%-57.6%) were TST negative (P<.001). Of 31 subjects who completed the TST protocol and the QFT protocol, 8 (25.8%; 95% CI, 10.4%-41.2%) were confirmed negative (P<.005).

CONCLUSIONS

A significant proportion of subjects with positive results of a previous TST were TST negative in this study, and a subset of these were confirmed negative. These individuals' TST status may have reverted or may never have been positive. It will be important in future studies to determine whether such individuals lack immunity to tuberculosis and whether they should be considered for reentry into tuberculosis screening programs.

Agreement between Mantoux skin testing and QuantiFERON-TB assay using dual mycobacterial antigens in current and former injection drug users

BACKGROUND

Individuals infected with non-tuberculous mycobacteria may elicit false-positive reactions on tuberculin skin testing. The QuantiFERON-TB (QFT) assay utilizes tuberculin and M. avium antigens and, therefore, may be more specific for latent tuberculosis infection. The objective of this study was to investigate the agreement between the QFT and single and dual antigen skin testing for detecting latent M. tuberculosis and assess the impact of cross-reactions from latent infection with other mycobacteria in inner-city injection drug users, a population at high risk for tuberculosis.

MATERIAL/METHODS

We studied the agreement of results from skin testing using tuberculin and purified protein derivative-Battey (PPD-B) with the QFT test using tuberculin and Mycobacterium avium sensitin (MAS) in 48 HIV-seronegative injection drug users.

RESULTS

The agreement between skin testing and the QFT assay for tuberculin was 73% (kappa = 0.45) and for PPD-B/MAS was 63% (kappa = 0.12). Agreement between skin test tuberculin dominance (tuberculin reaction > or =5 mm greater than PPD-B) and QFT tuberculin dominance (proportional difference between MAS and tuberculin reaction of > or =10%) was 75% (kappa = 0.53). All subjects tuberculin dominant by skin test were also QFT positive for tuberculin. Agreement between skin test Battey dominance and QFT avium dominance was 83% (kappa = 0.12).

CONCLUSIONS

Results from the QFT assay and skin testing demonstrated moderate concordance in identifying subjects with latent tuberculous infection, and use of dual antigens did not appreciably improve the agreement between the two methods.

Tuberculosis prevention for non-US-born pregnant women

OBJECTIVE

The purpose of this study was to evaluate whether non-US-born pregnant women receiving prenatal care are targeted for treatment of latent tuberculosis (TB) infection (LTBI) with isoniazid (INH) to prevent active TB.

STUDY DESIGN

This was a retrospective chart review study of 730 non-US-born pregnant women receiving care at 5 New York City prenatal clinics from 1999 to 2000.

RESULTS

Among 678 women with known tuberculin skin test (TST) status, 341 (50.3%) had a TST-positive result, including 200 who were newly diagnosed. Of 291 TST-positive women with no previous LTBI treatment or history of TB, 27 (9.3%) completed > or =6 months of INH. In a subset with detailed follow-up, the most important reasons for not completing treatment were nonreferral for evaluation of a TST-positive result (30.9%), not keeping the appointment (17.9%), and nonadherence with prescribed treatment (34.6%).

CONCLUSION

The prenatal setting represents a missed opportunity to link TST-positive non-US-born women with LTBI treatment and support for treatment completion.

Teste tuberculínico na estimativa da prevalência de infecção por Mycobacterium tuberculosis em populações indígenas do continente americano: uma revisão da literatura

Realizou-se revisão sistemática da literatura sobre trabalhos que utilizaram PPD para estimar a prevalência e o risco de infecção tuberculosa entre os povos indígenas do continente americano. Foram consultadas as bases de dados MEDLINE e LILACS, utilizando-se a combinação dos seguintes descritores: "tuberculosis", "south american indians", "north american indians", "tuberculin skin test", "PPD", "risk assessment" e "BCG vaccine", para o período de 1974/2004. Foram incluídos estudos longitudinais e seccionais que consideraram como desfecho a prevalência de infecção por M. tuberculosis definida por reações > 5mm e > 10mm. Foi possível localizar 54 artigos, dos quais 16 foram incluídos nesta revisão. Com base nos artigos selecionados, foram contabilizadas 13.186 pessoas, sendo 50% menores de 15 anos. A prevalência oscilou de 0 a 93,4% e o risco de infecção de 0 a 35,4%. A análise da heterogeneidade nas condições ambientais e nos métodos utilizados para estimar a infecção entre os estudos revisados demonstrou que o teste tuberculínico foi oportuno em decisões clínicas (p.ex., início da quimioprofilaxia), e que os inquéritos tuberculínicos são úteis para avaliar as medidas de controle da tuberculose entre os povos indígenas.

[Analysis on the results of TB skin test in medical students]

PURPOSE

To obtain baseline, medical students are recommended to make two-step tuberculin skin tests when they are in good physical health, as the baseline information to detect later tuberculosis infection. We investigated a method to obtain appropriate baseline data, because the accurate method of this test was not yet established.

SUBJECTS AND METHODS

The subjects were the tuberculin skin test results of 1066 medical students who were subjected to different methods of tuberculin skin test (58% tested once, 37% tested twice, and 5% tested three times). We retrospectively made multi-dimensional analysis about these data.

RESULTS

(i) In the first tuberculin skin test, 20% of the results were negative. (ii) When repeated with intervals between one to four years, the diameters of erythema gradually increased due to the effect of prior tests. (iii) The difference in size of erythema between the first tuberculin skin test and the repeated tests was less than 10 mm. (iv) When two-step tuberculin skin test was repeated, significant increase in the diameters of erythema were demonstrated in the second test (P = 0.0048). (v) Regarding booster phenomenon, it apparently lasted for one year, and it also remained after two years or over. CONSIDERATION: Thus, repeated tuberculin skin tests performed in good physical health was difficult to interpret measuring the diameters of erythema to detect tuberculosis infection. Thus, the diagnostic value of a tuberculin skin test was reduced while it requires unnecessary time and expenditure for its implementation.

CONCLUSION

It seems to be appropriate for medical students to make a two-step tuberculin skin tests, soon after their enrollment, and the results should be used as a baseline to detect possible later tuberculosis infection.

[The results of patients follow up at Gaziantep Number II Dispensary of Tuberculosis Control in the year 2004]

In this study, the aim was to investigate the performance of number-II Dispensary of Tuberculous Control (DTC) in Gaziantep in 2004. The patients diagnosed to have tuberculosis between 2004 January 1st and 2004 December 31st were included. The patients registries were evaluated retrospectively. The mean age of the patients was 28.92+/-14.43 years (ranged between 1-68), 70.5% of the cases were male, and 72.5% of the cases were between 15-44 years old. Forty-two (82.3%) of the cases had the diagnosis of lung tuberculosis. 47% of them did not have any health insurance. The symptoms detected in the patients were cough, night sweats, sputum and hemoptysis respectively. There was no symptom registry in ten patients (19.6%). Sputum analysis to detect acid-fast bacilli (AFB) was done in 18 patients (19.6%). AFB was perfomed in 3.9% of the patients following two-months of therapy, and in 1.9% of the patients at the end of the therapy. Diagnostic tuberculous culture was performed in only one patient (1.9%). There was no tuberculous culture performed neither at the second month nor at the end of the therapy course. AFB was found to be positive in direct or concentrated sputum samples in eight (44.4%) of the patients. All the patients were evaluated with radiographies. The eritrocyte sedimentation rate was measured in 33.3%, 9.8%, and 15.6% of the patients before the therapy, at the end of the two months of therapy, and at the end of the therapy, respectively. The diagnosis was established with radiology clinical findings in 34 patients (66.6%). Directly observed therapy was performed in one patient (1.9%). The cure rate among smear positive patients was 12.5%, and the 100% of the patients were completed the therapy. There exists many problems with tuberculosis "warfare" and we believe the solution lies in DOTS.

[Tuberculosis screening results made at primary schools in Cizre]

Tuberculosis (Tbc) gained importance as a public health problem in the recent years. The course of the disease is more severe in childhood. Tbc screening was made by The Tuberculosis Control 11th Group Presidency on the primary school students in Cizre, in November 2005. A total of 2242 children have been taken to this study. Of the children, 1130 (50.4%) were boys and 1112 (49.6%) were girls. The mean age of the children was 6.9+/-0.8 (range, 4-14) years. Concerning Bacillus Calmette-Guerin (BCG) vaccine scar, 1676 (74.7%) children had no scar, 536 children (23.9%) had single scar, and 32 children (1.4%) had double scar. The mean diameter of the tuberculin skin test (TST) was 2.1+/-2.7 mm. Regarding sexuality and TST mean diameter, statistically significant relation was not detected between girls and boys (p=0.3). The mean diameter of TST were 1.5+/-1.4 mm, 3.5+/-4.0 mm and 11.2+/-3.3 mm in the children with no BCG scar, in those with single BCG scar, and in those with double BCG scar, respectively. Of the TST results of all children, 2065 (92.1%) were negative, 101 (4.5%) were attributed to BCG, and 76 (3.4%) were positive, respectively. The rate of positiveness of TST was 1.2% in the children with no BCG scar, 8.9% in the children with single BCG scar, and 50% in the children with double BCG scar, respectively. A statistically significant correlation between the increase in the BCG scar number and the increase in the TST mean diameter was detected (p<0.05). Of the children who were likely to have Tbc, 139 (6.2%) were advised to apply at the dispensary. Single BCG vaccination was inadequate in the children. We suggest encouraging the families about postpartal single BCG vaccination. Furthermore, school screenings should be paid greater attention.

[Future supply of tuberculin in Germany]

The manufacturers of the only tuberculin available up to now in Germany for intradermal TB tests according to Mantoux, Chiron Vaccines Behring, in 2004 unexpectedly stopped the production of the tuberculin Behring GT (GT="gereinigtes Tuberkulin"-purified protein derivative tuberculin). Only residual stocks were sold during the preceding months. The stocks of GT 10 were already depleted at the beginning of 2005, while there are small supplies left of GT 100 and GT 1000. As a temporary solution, Chiron Vaccines Behring is offering to import the Italian tuberculin Biocine PPD 5 IE lyophil produced by Chiron S.r.l. in Siena. As this is not licensed for sale in Germany, it is necessary to obtain an exceptional prescription (Einzelverordnung) according to section sign 73 (3) of the Federal Law Relating to the Manufacture and Distribution of Medicine (Arzneimittelgesetz, AMG). In the long term, Chiron Vaccines Behring plan to secure the supply of tuberculin in Germany by importing, starting in the summer of 2006, the tuberculin produced by Chiron Vaccines Evans in the UK (PPD Evans). However, these plans involve changing over to a different type of tuberculin twice within a very short period of time. Another problem is the unresolved issue of bioequivalence. Besides the above-mentioned tuberculins produced by Chiron Vaccines, a further possibility would be the import of the tuberculin PPD RT23 SSI of the Statens Serums Institute (Copenhagen/Denmark), which is recommended by the World Health Organization (WHO) as the standard tuberculin and which has already been introduced in several European countries, or of other tuberculins such as Tubersol (PPD CT68), which is used in the US. Together with the Robert Koch Institute (RKI) and the Paul Ehrlich Institute (PEI), the German Central Committee against Tuberculosis (DZK) is striving to find a solution, in view of the urgent need for an uninterrupted supply of tuberculin in Germany for diagnostic purposes and contact tracing. A uniform tuberculin should be used in all German regions as a basis to secure a standardized testing procedure and national comparability of test results. The estimated annual requirement for Germany is two million tuberculin test doses. The Statens Serum Institute is currently evaluating the possibility of licensing PPD RT23 SSI in Germany. Chiron Vaccines Behring communicated that it is not aiming to have the Biocine tuberculin licensed for Germany but intends to apply for a license for the tuberculin PPD Evans. Sanofi Pasteur MSD at this point does not intend to have a tuberculin like Tubersol (PPD CT68) licensed for Germany. Until a licensed tuberculin is again available in Germany, it would be very useful if, especially in settings where stocks of tuberculin are essential (e.g. public health services or hospital dispensaries), an exceptional import license could be obtained.

Cost-effectiveness of tuberculosis control strategies among immigrants and refugees

Today, in Western Europe, Canada and the USA, more than half of all new active tuberculosis (TB) cases occur among foreign-born migrants. This article examines the impact of migration from high TB-incidence to low TB-incidence countries, and compares the cost-effectiveness of different TB control strategies. A Medline search was conducted to identify relevant English language publications prior to December 2003. Additional articles were identified from the reference lists from these publications. Despite the high proportion of active cases in low-incidence countries attributable to foreign-born residents, the public health impact is relatively low. Current chest radiograph screening programmes have little impact and are not cost-effective. Screening with sputum culture would improve cost-effectiveness marginally. Treatment of latent infection detected through screening with tuberculin skin testing or chest radiographs may require coercive measures to maximise impact and cost-effectiveness. In contrast, contact tracing, particularly within ethnic communities, appears to be more cost-efficient and less intrusive. In low-incidence countries, screening of migrants at entry has little overall impact and is not a very cost-effective tuberculosis control strategy. More effective alternatives include contact tracing delivered through primary care and increased investment in global tuberculosis control.

Tuberculin skin test: estimation of positive and negative predictive values from routine data

OBJECTIVE

To estimate, using routinely available data, the predictive values of tuberculin testing with 2TU RT23 for detection of latent tuberculosis infection (LTBI) in the Dutch population as a basis for recommendations on cut-off values at various levels of infection prevalence.

DESIGN

Smoothed distributions of TST reactions among 312 tuberculosis patients and 2848 healthy non-BCG-vaccinated persons were used to estimate the sensitivity and specificity at various cut-off values.

RESULTS

Sensitivity was 98.9% at 5 mm, 95.4% at 10 mm and 79.8% at 15 mm cut-off. Specificity with the corresponding cut-offs was 95.3%, 96.3% and 97.1% before and 98.0%, 98.8% and 99.6% after adjustment for presumed LTBI. At 10 mm, the positive predictive value (PPV) was > 75% if the infection prevalence in the tested population was at least 10%, but strongly declined with lower prevalences. For lower prevalences a cut-off of 15 mm was proposed, as this results in a higher PPV without greatly affecting the negative predictive value.

CONCLUSION

Estimation of the predictive values of the TST from routine data can be useful for establishing cut-off values for detection of LTBI in different populations with different tuberculin preparations.

[Tuberculin skin test screening in a military school in Istanbul city center]

To investigate the reason of high incidence of annual patients with tuberculosis (TB) in a military school previously known by screening tuberculin skin test (TST) and finding out the proportion of annual infection risk (PAIR), the prevalance of TB infection and the distribution for each grades. Our study is a cross-sectional epidemiologic study made about TB infection. TST were screened for all students in the school. 5 TU PPD was injected to every student and after 72 hours, the results were evaluated by measuring the diameter of enduration. Test was repeated after 10 days for negative reactions. Age, sex, the number of BCG wound, smoking and dwelling for last 5 years were asked from the students and their answers were recorded. More than 10 mm enduration for cases who had no BCG and 15 mm enduration for cases who had BCG were accepted positive. Chest roentgenogram was taken for each student enrolled into the study. Infection prevalance and PAIR were calculated after tests and measurements. The total number of students was 948. Of 917 (96.7%) were male and 31 (3.3%) were female. The mean age was 19.72 +/- 1.25. The mean of TST was 12.79 +/- 5.96 mm for all students. According to the number of BCG scar, the numbers of students, percentage and the mean of TST were like that 70 (7.3%) cases no BCG scar 8.41 +/- 7.87 mm, 393 (41.4%) students one BCG scar, 11.94 +/- 6.26 mm, 343 (36.1%) cases two BCG scars, 13.74 +/- 5.12 mm, 142 (14.9%) students three or more then three scars, 14.97 +/- 4.11 mm. In the students who had no BCG, TST positivity was 50%. TB infection prevalance of entire school and PAIR were 46% and 3.44% (respectively). In this study, we found that increased number of BCG wound associated with the increased diameter of TST enduration. The proportion of unvaccinated students was similar to the same age population in our country but it showed differences in the distribution of regions. The students who started first grade had serious TB infection risk in their first school year. We think that PAIR values derived from TST conversions done in high risky community by screening annual TST could show all aspects of TB infection risk in those community.

Documented tuberculin skin testing among infliximab users following a multi-modal risk communication interventions

PURPOSE

Following its licensure, tuberculosis (TB) was reported as a potential adverse effect of infliximab. Subsequently, the product circular was changed to recommend tuberculin skin testing before patients received infliximab, which was reinforced by several risk communication efforts. The aim of this study was to evaluate patterns and predictors of documented tuberculin skin testing in patients before and after manufacturer, federal, and academic risk communications.

METHODS

Patients administered infliximab were identified from 11 health plans located throughout the United States, and claims data were examined to determine whether the patients had received a tuberculin skin test. Patients were divided into three cohorts depending on the timing of their first infliximab treatment in relation to the risk communication efforts.

RESULTS

The overall tuberculin skin testing rate doubled from 15.4% in the first cohort to 30.9% in the last cohort, while the rate of pre-infliximab treatment testing increased from 0 to 27.7% (Chi-squared test for trend, p < 0.0001 for both). Tuberculin skin testing rates were significantly higher in women, those with a diagnosis of rheumatoid or psoriatic arthritis, and those with a rheumatologist as prescriber. After multivariable analysis, only rheumatologist remained significantly associated with tuberculin skin testing.

CONCLUSIONS

Although the tuberculin skin testing rate was relatively low overall, tuberculin skin testing doubled over 30 months of ongoing risk communication efforts and under ascertainment likely occurred. We also found variation in the tuberculin skin testing rate associated with physician specialty. This study demonstrates a significant change in patient care following risk communication efforts.

Predictors of Positive Tuberculin Skin Test (TST) Results after 2‐Step TST among Health Care Workers in Manitoba, Canada

BACKGROUND

Baseline 2-step tuberculin skin testing (TST) is recommended for health care workers (HCWs) to identify cases of the "boosting phenomenon" (i.e., a negative initial TST result followed by a positive result) and to track the risk of acquiring occupational tuberculosis. However, the 2-step TST has been shown to be insufficient to identify all cases of the booster phenomenon in older adults and refugees. The objective of this study was to identify whether a history of bacille Calmette-Guérin (BCG) vaccination and foreign birth--variables that are known to be associated with the booster phenomenon--remain predictors of a positive TST result in a group of HCWs documented to have negative 2-step TST results (i.e., 2 TSTs done 7-28 days apart with indurations <10 mm in diameter).

METHODS

We performed a retrospective analysis of an employee database in a tertiary care hospital in Winnipeg, Canada. The study population was comprised of 698 HCWs with negative 2-step TST results who underwent a TST 0-2 years after completion of the 2-step procedure.

RESULTS

Forty-six HCWs (6.6%) had a positive TST result 0-2 years after the 2-step test. In a multiple logistic regression analysis controlling for age, BCG vaccination, foreign birth, sex, and work setting, only history of BCG vaccination (odds ratio [OR], 8.38; 95% confidence interval [CI], 4.04-17.4), foreign birth (OR, 3.19; 95% CI, 1.53-6.62), and high-risk work setting (OR, 2.93; 95% CI, 1.44-5.95) were associated with a positive TST result.

CONCLUSIONS

Even for HCWs with negative results of 2-step TST, foreign birth and history of BCG vaccination are associated with a positive result of a future TST. Some positive TST results in such HCWs are related to nonoccupational factors, including delayed boosting, rather than to conversion due to recent tuberculosis contact.

Can BCG-vaccinated children be included in tuberculin surveys to estimate the annual risk of tuberculous infection in India?

SETTING

Selected villages in three defined zones of India.

OBJECTIVES

To compare the estimated prevalence of tuberculous infection among children with and without bacille Calmette-Guérin (BCG) scar.

STUDY DESIGN

During a nationwide tuberculin survey, 1-9-year-old children were tuberculin tested using 1TU-PPD RT23 with Tween 80.

RESULTS

In the 5-9 year age group, subgroups of tuberculous infected children could be seen as distinct humps among those with or without BCG scar, but not in those aged 1-4 years. In children aged 1-4 years, the estimated prevalence of infection was respectively 3.5%, 3.8% and 3.6% among children without BCG scar, and 4.8%, 4.7% and 4.5% among children with BCG scar in the western, northern and eastern zones. In those aged 5-9 years, the estimated prevalence was respectively 10.4%, 11.0% and 9.1% among children without BCG scar and 11%, 11.9% and 8.7% among children with BCG scar in the three zones. Thus, in children aged 1-4 years, the estimated prevalence among those with BCG scar was considerably higher than in those without BCG scar. This difference was small in those aged 5-9 years.

CONCLUSION

Tuberculin surveys may be conducted irrespective of BCG scar status among children aged 5-9 years, when BCG vaccination is given using Danish 1331 strain during infancy under the Expanded Program of Immunization.