Skin testing with tuberculin-PPD is most widely used in screening for:
Active TB
Latent M. tuberculosis infection
Miliary TB
Overwhelming TB
Skin testing with tuberculin is used in screening for latent M. tuberculosis infection (LTBI). The test is of limited value in active TB. False-negative reactions are common in immunosuppressed patients and in overwhelming TB. False-positive reactions may be caused by infections with nontuberculous mycobacteria and BCG vaccination. Ref: Harrisons Principles of Internal Medicine, 18th Edition, Page 1351