Population characteristics: Northern California <i>H. pylori</i>/LTBI studies.

Characteristics of healthy individuals referred through public health clinics in Santa Clara County, CA, USA who completed tuberculin skin test [TST], QuantiFERON-TB GOLD® interferon-γ release assay, and H. pylori serology. 1152 (91%) born in Latin America; TST: tuberculin skin test, +, ≥ 10mm induration (includes 18 prior positives not retested); QFT (QuantiFERON-TB-GOLD® including M. tuberculosis antigens ESAT6 and CFP10 and M. tuberculosis antigen TB7.7; +: ≥0.35 IU/ml IFN-γ difference over unstimulated well. 2Latent TB infection [LTBI]: either TST+ or QFT+ for analysis; 7 (2%) individuals reported prophylactic TB treatment 3–34 years prior to enrollment. All factors significant at p<0.05 (2-sided χ2 test).