RFLP results of 15 active TB cases with positive AFB culture.

<p>The banding patterns of 15 outbreak strain isolates are completely same. RFLP = restriction fragment length polymorphism; TB = tuberculosis; AFB = acid fast bacilli.</p

Receiver Operating Characteristic (ROC) curves for prediction of TB cases using different cut-off points of TST induration size.

<p>(A) For all contacts, the overall accuracy was higher with the criteria of TST ≥10 mm than with that of TST ≥15 mm to predict TB cases. (B) But, for the contacts with TST+/QFT- results, the overall accuracy was the most highest with the criteria of TST ≥15 mm. TST = tuberculin skin test; AUC = Area under the curve.</p

Scheme of TB outbreak in a single high school in Korea.

<p>Each symbol in column represents one student and placed at the point at which the student was diagnosed as active TB.<b>●</b> = Active TB cases with positive AFB culture; <b>○</b> = Clinical TB cases with negative AFB culture; ▲ = Active TB cases with positive AFB culture and smear developed during follow-up among contacts who were TST+/QFT-; <b>Δ</b> = Clinical TB cases with negative AFB culture developed during follow-up among contacts who were TST+/QFT-; TB = tuberculosis; AFB = acid fast bacilli; TST = tuberculin skin test; QFT = QuantiFERON-TB Gold In-Tube test.</p

Clinical characteristics of TB contacts.

<p>Clinical characteristics of TB contacts.</p

The results of QFT tests among the TST+ reactors based on TST cut-off value.

<p>The results of QFT tests among the TST+ reactors based on TST cut-off value.</p

Clinical characteristics of 7 contacts who developed TB during follow-up.

<p>Clinical characteristics of 7 contacts who developed TB during follow-up.</p