en Infectious Diseases Infectious Diseases Original Article Original Article <p dir="ltr" style="text-align: justify;"><span style="font-family: times new roman;"><span style="color: rgb(0, 0, 255);"><strong><em>Background: </em></strong></span>Prompt diagnosis and treatment of latent tuberculosis (TB) infection (LTBI) are needed to control TB. The aim of the study was to compare the performance of Quanti FERON-TB test (QFT) with conventional TST for the diagnosis of LTBI.</span></p> <p dir="ltr" style="text-align: justify;"><span style="font-family: times new roman;"><span style="color: rgb(0, 0, 255);"><strong><em>Methods:</em></strong></span> In this analytical - comparison study, we enrolled 87 nurses working in teaching hospitals in Ahvaz. All study subjects were tested by TST.&nbsp; TST results were interpreted as positive if induration was more than 10 mm. If the level of QFT after stimulation was equal or greater than 0.35 IU/ml, test was considered as positive. Data were analyzed with SPSS program<span dir="RTL">.</span> QFT results compared with induration in TST and its relation to all variables were investigated.</span></p> <p dir="ltr" style="text-align: justify;"><span style="font-family: times new roman;"><span style="color: rgb(0, 0, 255);"><strong><em>Results:</em></strong></span> The rate of LTB diagnosis by TST and QFT was 31% and 35.6%, respectively. There was no significant difference between TST and QFT in LTB diagnosis (P=0.62). Among the 56 subjects who were TST- negative, 14 cases (approximately 25%) were QFT- positive and 42 (75%) were QFT- negative. Among&nbsp;&nbsp; the 31 cases (35.6%) that had TST- positive, 13 (42%) were QFT-positive and 18 (58%) were QFT- negative. The overall percent agreement was 63.2% (k=0.139, P=0.69), discordance %=15.9-20.7, sensitivity= 41.5% and specificity=75.5%.</span></p> <p dir="ltr" style="text-align: justify;"><span style="font-family: times new roman;"><span style="color: rgb(0, 0, 255);"><strong><em>Conclusion:</em></strong></span> Diagnostic value of QFT is similar to TST, when there is strong clinical and epidemiological evidence of LTB in a nurse with negative TST, adding QFT to diagnostic evaluation is associated with increased rate of LTB diagnosis.</span></p> Latent tuberculosis infection, Quanti FERON-TB test, tuberculin skin test, Health care workers 82 87 http://caspjim.com/browse.php?a_code=A-10-28-5&slc_lang=en&sid=1 Seyed-Mohammad Alavi alavi.seyedmohammad@yahoo.com, alavi-sm@ajums.ac.ir 10031947532846005209 10031947532846005209 Yes Jundishapur University of Medical Sciences,Ahvaz, Iran shokrollah salmanzadeh ssalmanzadeh@yahoo.com 10031947532846005210 10031947532846005210 No Ahvaz Jundishapur University of Medical Sciences, Iran Hajar Abbasifar habassifar@yahoo.com 10031947532846005211 10031947532846005211 No Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran