Even in the third millennium with an old friend: issues in the interpretation of tuberculin skin test results

Stremeći prema niskoj incidenciji, a u konačnici i eliminaciji tuberkuloze potrebno je intezivno sudjelovati u mjerama suzbijanja i sprječavanja tuberkuloze, primarno kroz rano otkrivanje i liječenje oboljelih, a zatim i kroz traženje kontakata tuberkuloznih bolesnika. Stoga identificiranje osoba s latentnom tuberkuloznom infekcijom, njihovo liječenje ili adekvatni nadzor, postaje nezaobilazna odrednica nacionalne strategije nadzora nad tuberkulozom. Trenutno su dva testa u uporabi za otkrivanje latentne tuberkulozne infekcije: tuberkulinski test i test otpuštanja gama interferona. Bez obzira što se dugo upotrebljava, još uvijek postoje brojne nejasnoće u tumačenju rezultata tuberkulinskoga testa, naročito u populaciji poput naše, koja je cijepljena Bacillus Calmette-Guerin cjepivom. Uz to postoje dvojbe oko tumačenja rezultata ponovljenih testiranja za otkrivanje nove infekcije u rizičnim skupinama, kao što su inicijalno tuberkulin-negativni kontakti tuberkuloznoga bolesnika. Stoga je cilj ovoga preglednoga rada pružiti smjernice za pravilnu interpretaciju rezultata tuberkulinskoga testiranja s posebnim osvrtom na konverziju, razloge lažno pozitivnih i lažno negativnih rezultata, buster fenomen, kriterije za razlikovanje konverzije od buster fenomena, promjene tuberkulinske reakcije zbog varijabilnosti u rezultatima testiranja, reverziju, testiranje trudnica, te buster efekt tuberkulinskog testiranja na testove otpuštanja gama interferona.As countries approach the low incidence of tuberculosis burden and subsequently its elimination phase, intensive efforts should be undertaken. Along with the most successful intervention in tuberculosis control, which is early detection and early treatment of tuberculosis patients, the importance of detection and treatment of latent tuberculosis infection and emergence of groups at particularly high risk of tuberculosis are gradually increasing. There are currently two tests used to detect latent tuberculosis infection: tuberculin skin test and interferon-gamma release assays. Although tuberculin skin tests have been used for decades, the interpretation of the results is not easy, especially in a population which has been vaccinated with Bacillus Calmette-Guerin vaccine. Particular problems have arisen with the use of repeated tuberculin tests to detect new infection in high-risk population such as initially tuberculin-negative contacts of tuberculosis patients. The aim of this review is to provide guidance for the proper interpretation of tuberculin test results, with special emphasis on conversion, reasons for false positive and false negative results, buster phenomenon, criteria for distinguishing conversion from buster phenomenon, changes in tuberculin reactions due to variability in test results, reversion, testing of pregnant women and buster effect of tuberculin test on interferon-gamma release

Epidemiological Patterns of Tuberculosis in Croatia in the Period 1996–2005

The last comprehensive publication on tuberculosis in Croatia and the earliest impact of war, besides the yearly routine reports, was done in 1996 in Croatian. We were, therefore, interested to explore incidence trends and to highlight the early post-war tuberculosis epidemiological patterns in the next ten years period (1996–2005). A retrospective analysis of epidemiological data on all registered tuberculosis cases in Croatia searching the databases of 21 Croatian Public Health Institutes and the National Tuberculosis Registry was made. During the study period, the total tuberculosis incidence rates in Croatia dropped from 45 to 25.8/100 000 inhabitants. The average highest age-specific rates were recorded in the age group 65 years being in decrease in all age groups. Paediatric cases (0–14 years) represented 4.5% of all cases. Tuberculosis cases among males were recorded in 64% cases, and 83.6% were indigenous population. Tuberculosis was bacteriologically confirmed in 67.7% cases. A low proportion of drug resistance (3.3%) was recorded. During 1985–2005, 56 tuberculosis cases among 242 AIDS cases were reported. Tuberculosis mortality showed a decreasing trend (p<0.001). However, tuberculosis has still had the highest mortality rates among infectious diseases in Croatia. Despite the War chain of events and tuberculosis programmatic changes, tuberculosis incidence rates in Croatia have been decreasing but they are still far away from national target, incidence rate of 10/100 000 declared in 1998 and much higher than in European Union and Western Europe. Tuberculosis among children, resistance to tuberculosis drugs and HIV prevalence, significant problems in many European countries, have not caused problems in tuberculosis control in Croatia. This favourable epidemiological situation must be kept and improved through strengthened tuberculosis control measures