Equivalence Study of Tuberculin Purified Protein Derivative in Comparison With a Reference Standard (PPD-S2)

Inclusion Criteria: 1. Males or nonpregnant females age 18 to 60 years 2. Documented PPD reactivity of 5 to 21 mm in the past, documented in a medical record. Self-reported PPD reactivity will be acc 3. Give written informed consent to participate 4. Generally healthy, as determined by medical history and targeted physical examination, if indicated 5. Possess 2 forearms that are free of burns, scars, eczema, or any physical deformity, which could impair injection of study prepar 6. Comprehension of the study requirements; expressed availability for the required study period, including readings at the nomina Exclusion Criteria: 1. Prior PPD test within the past 30 days 2. Subject is of childbearing potential and unable to use contraceptives; is planning pregnancy; is pregnant or lactating 3. History of anaphylactic reaction, severe positive tuberculin reaction (eg, ulceration, necrosis) or other severe reaction to PPD in 4. Subject received a Bacillus Calmette-Guérin (BCG) vaccination in the past, or was born or lived outside the US as a child and is 5. Presence of conditions that may suppress TST reactivity -