CDC Logo Tuberculosis Information CD-ROM   Image of people
jump over main navigation bar to content area
TB Guidelines
Surveillance Reports
Slide Sets
TB-Related MMWRs and Reports
Education/Training Materials
Ordering Information


U.S. Department of Health and Human Services


Guide for Primary Health Care Providers: Targeted Tuberculin Testing and Treatment of Latent Tuberculosis Infection


Latent tuberculosis infection (LTBI) is infection with Mycobacterium tuberculosis organisms (tubercle bacilli) without signs and symptoms nor radiographic or bacteriologic evidence of tuberculosis (TB) disease. When small droplet nuclei containing the tubercle bacilli reach the alveoli, they are engulfed by macrophages and usually destroyed. However, when a number survive and multiply, they can cause LTBI.

Approximately one third of the world’s population is infected with M. tuberculosis. In the United States, it is estimated that 914 million people have LTBI. Without treatment, approximately 510% will progress to TB disease at some point in their lifetime. Identifying and treating those at highest risk for TB disease will help us move toward elimination of the disease. Primary care providers play a key role in achieving the goal of TB elimination because of their access to high-risk populations. 

The Centers for Disease Control and Prevention (CDC) and the American Thoracic Society (ATS) published guidelines in the June 9, 2000 issue of Morbidity and Mortality Weekly Report (MMWR), entitled Targeted Tuberculin Testing and Treatment of Latent Tuberculosis Infection. In addition, updates to the 2000 guidelines have been published. Major changes from prior recommendations fall into three categories: testing for LTBI, treatment of LTBI, and clinical monitoring (see Table 1). 

Terminology used in the guidelines also reflects a change. The commonly used terms “preventive therapy” and “chemoprophylaxis” have been replaced with “treatment of latent TB infection (LTBI).”  This more accurately describes the use of a treatment regimen to prevent the development of TB disease in persons with LTBI (see Table 2).

This document is not meant to be used as a substitute for the guidelines, but rather as a ready and useful reference that highlights the main points of those guidelines.


Released October 2008
Centers for Disease Control and Prevention
National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention
Division of Tuberculosis Elimination -

Please send comments/suggestions/requests to:, or to
CDC/Division of Tuberculosis Elimination
Communications, Education, and Behavioral Studies Branch
1600 Clifton Rd., NE - Mailstop E-10, Atlanta, GA 30333