%0 Journal Article %A Jose-Maria Garcia-Garcia %A Juan-Jose Palacios %A Begoña Gonzalez-Gonzalez %A Ana Fernandez-Quiroga %A Henar Villar %A Manuel Villanueva %A Gema Castaño %A Kaoutar El Boutaibi Faiz %A Fernando Alvarez-Navascues %A Andrés Sanchez-Antuña %A Jose-Antonio Gullon %A Jesus Allende %A Manuel Martinez-Muñiz %A Jose-Manuel Fernandez-Carreira %T Cut-off point for tuberculin skin test (TST) and QuantiFERON (QTF) in the diagnosis of tuberculosis infection (TI) in a study of contacts of tuberculosis (TB) %D 2012 %J European Respiratory Journal %P P424 %V 40 %N Suppl 56 %X Aim.To determinate the cut-off for TST assuming a diagnosis of TI when QTF was ≥ 0.35 IU/mL Moreover, we calculated the cut-off for QTF assuming the diagnosis of TI when TST was ≥ 5 mm.Methods.We studied prospectively 414 close contacts from 82 TB patients. We performed “QuantiFERON TB GOLD in Tube “ (according to the manufacturer's instructions, Cellestis, Australia) and the same day after venous blood puncture for QTF, TST (Mantoux technique with 2 UI of PPD RT23 with lecture 72 hours later). We studied sensibility, specificity and analysis “Receiver Operador Characteristics” (ROC). The positive and negative predictive values (PPV, NPV) were calculated based in our proportion of TI of 52,9%.Results.Assuming as “gold standard” of TI a value of QTF 0.35, the best cut-off of TST was 5mm.Assuming as “gold standard” of TI a value of 5mm, the best cut-off of QTF was 0.26.Conclusion.1. In a study of TB contacts the cut-off for TST of 5 mm was the best for the diagnosis of TI.2. Although the established cut-off for QTF is 0.35, lower values as 0.26 can be taken into account. %U https://erj.ersjournals.com/content/erj/40/Suppl_56/P424.full.pdf