Background and Objective: Tuberculin skin test (TST) is the standard method for diagnosis of LATENT tuberculous INFECTION. Positive results of TST (significant induration) may be seen in persons with LATENT M. tuberculosis INFECTION and negative results of this test may be seen in patients with active tuberculosis. After performing TST false positive reactions may be seen with nontuberculous mycobacterial INFECTIONs or false negative results may be encountered in anergic patients with tuberculosis disease. Quantiferon TB Gold test (QFT) is a new diagnostic test which assays the amount of released interferon gamma from peripheral blood lymphocytes in response to M. tuberculosis antigens. The purpose of this study was to determine the degree TST and QFT correlation.Materials and Methods: This descriptive study carried out on 72 nurses of two internal medicine and infectious diseases wards of Imam Reza and Imam Khomeini hospitals in Kermanshah located in West of Iran, during 2009.58 of nurses were vaccinated with BCG vaccine and none of them had any immune compromising condition. TST was performed by intradermal injection of 0.1 ml of standard tuberculin test (5 TU) and QFT was performed 48 hours then after using peripheral whole blood. The amount of released interferon gamma from lymphocytes in response to antigens were measured by ELISA method.Results: Three of nurses excluded and this study was done on 69 nurses. Overall the degree of agreement of TST and QFT was 63.7% (P=0.69 and Kappa=0.139). The degree of discordance between these tests in PPD negative but QFT positive persons was 15.94% and in PPD positive but QFT negative persons was 20.3%. The sensitivity and specificity of QFT was 41.67% and 75.56% respectively. The degree of agreement of TST and QFT in vaccinated and unvaccinated nurses was 63.8% (Kappa=0.143) and 66.67% (Kappa=0.54) respectively.Conclusion: There was no significant difference between QFT and TST in diagnosing LATENT tuberculous INFECTION.

The members of Mycobacterium tuberculosis complex (MTBC) known as causative agents of human tuberculosis. Tuberculosis INFECTION is one of the most important occupational risks for healthcare workers (HCWs) in most countries، such as Iran. In general، there are two types of tuberculosis، they include: LATENT INFECTION and active TB. LATENT tuberculosis INFECTION (LTBI) means: a patient is infected with Mycobacterium tuberculosis but، the patient does not have active tuberculosis، clinical symptoms and radiological findings. According to studies، TB INFECTION from patients to health care workers، depending on geographic region and economic situation is two to five times more than general population. The lowest incidence and the highest rates of LTBI prevalence among HCWs were 7% in Mashhad and 82. 8% in Zahedan respectively. The risk factor acquisition of TB INFECTION was a significant relationship with certain hospital wards (lung disease unit، laboratory، etc. )، Increasing age and duration of employment. And results of this study show that TB is a significant problem among HCWs in Iran. INFECTION control and personal protective measures with training programs to patients and HCW is required to reduce the occupational risk of TB. Early detection of Mycobacterium tuberculosis and prevention treatment in people with LATENT TB are key elements in control of tuberculosis. Until now، different methods for detection of LATENT tuberculosis INFECTION has been introduced that are not gold standard none of them. However، the most important methods، tuberculin skin test and the tests that based on measuring the production of interferon gamma are recommended، but each one of them has advantages and disadvantages. However، in all the articles of the tuberculin skin test is used for screening and early diagnosis of LATENT tuberculosis INFECTION. So، the aim of this study was to Incidence and prevalence of LATENT tuberculosis INFECTION in health care workers and risk factors، advantages and disadvantages of each method for diagnosis of LATENT tuberculosis INFECTION and evaluate different strategies for reducing the incidence of LATENT tuberculosis INFECTION in health care workers.

2LATENT tuberculosis INFECTION (LTBI) prevalence varies dramatically by region, with one-fourth of the world's population infected. The number of people with LTBI progressing to active tuberculosis illness (aTB) should be decreased to meet the WHO End TB Strategy objective of decreasing worldwide tuberculosis incidence by 2030. Current tuberculosis (TB) diagnostic methods are based on detecting an immune response to mycobacterial antigens injected into the skin or in vitro simulations in interferon-gamma release assays. Both tests have low sensitivity, which cannot distinguish between LTBI and aTB. Therefore, various techniques, such as alternate cytokine detection and employing novel antigens, are being studied to increase the accuracy of these tests.  In addition, novel antigens can be used to monitor aTB progression and response to treatment. This review aims to assess current available diagnostic tools and evidence on novel Mycobacterium tuberculosis (Mtb) antigens for LTBI diagnosis and select the most promising antigens for future research.

Background and Objectives: Tuberculosis is one of the main reasons for mortality in liver transplant recipients. Since Iran is considered as a tuberculosis-endemic country, the present study aims to evaluate the outcome of LATENT tuberculosis infec-tion in transplant recipients after liver transplantation. Materials and Methods: The present analytical cross-sectional study was performed on transplanted patients in Imam Khomeini Complex Hospital in Tehran Iran from 2006 to 2016. All patients with positive tuberculin skin test were enrolled. Variables including demographic information, therapeutic and outcome data were gathered and analyzed. Results: Among 675 transplant recipients, 100 patients had positive tuberculin skin test (14. 8%). Sixty seven percent of recipients were men and the mean age was 72. 67 ± 1. 3 years. All patients' received Isoniazid prophylaxis before transplan-tation. The mean duration of anti-tuberculosis prophylaxis before and after transplant were 2. 7 ± 1. 9 and 3. 6 ± 5. 5 months, respectively. Tuberculosis has not been occurred in none of these patients after a mean follow up time of 45. 21 ± 3 months. During the study period, four subjects infected by Mycobacterium tuberculosis, while their skin test was negative before transplant. Conclusion: According to our study, tuberculin skin test is a reliable and sensitive test for diagnosis of LATENT tuberculosis in liver transplant candidates. Isoniazid prophylaxis is well tolerated in patients with end stage liver diseases and liver transplant recipients.

Context: It has been estimated that one-third of the world’s population are suffering from LATENT tuberculosis INFECTION (LTBI). In order to control tuberculosis in high-risk groups proper diagnosis and treatment is essential.Evidence Acquisition: Useless and expensive tests such as unfocused population-based tests can lead to futile and unnecessary treatments. Targeted screening approaches and individualization of LTBI treatment protocols must be a priority.Results: Diagnostic methods with immune based tests such as the tuberculin skin test (TST) or interferon gamma release assays (IGRA) can accurately detect LTBI. However, interferon-gamma release assays have higher specificity than TST in Bacille Camette-Gurin (BCG)-vaccinated populations, both tests are precise to identify LATENT tuberculosis. However, it is of great concern that both tests have insignificant roles in predicting risk of progression to active tuberculosis.Conclusions: Here we review the clinical applications, advantages, and limitations of the tuberculin skin test and interferon-gamma release assays and provide an overview of the most recent systematic reviews conducted for the comparison of these tests.