This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
Skin testing with tuberculin-PPD is most widely used in screening for: 
Select and explain. 
A. Active TB, B. Latent M. tuberculosis infection, C. Miliary TB, D. Overwhelming TB
B: Latent M. tuberculosis infection
Answer: B: Latent M. tuberculosis infection 
Explanation: 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