Who Does Not Need Treatment for Latent TB
Low-risk individuals with positive tuberculin tests (≥15 mm induration) who are over age 35 and have no additional risk factors generally do not require treatment for latent TB due to the increased risk of hepatotoxicity outweighing the benefit. 1, 2, 3
Populations Where Systematic Testing and Treatment is NOT Recommended
The WHO explicitly states that systematic testing for LTBI is not recommended in the following groups unless they already meet high-risk criteria:
- People with diabetes mellitus 1
- People with harmful alcohol use 1
- Tobacco smokers 1
- Underweight individuals 1
The rationale for this conditional recommendation is based on very low quality of evidence, paucity of data on benefits and harms, and doubts about operational feasibility in these populations. 1
Age-Based Considerations for Low-Risk Individuals
For persons over age 35 without additional risk factors, the risk of isoniazid-induced hepatotoxicity must be weighed against the risk of tuberculosis progression. 3
- Treatment is generally not recommended for low-risk individuals over age 35 with positive tuberculin tests and no additional risk factors 2
- The CDC and ATS emphasize that infected persons at high risk should be offered treatment irrespective of age 1, 2
- The age cutoff of 35 years applies only to individuals without additional risk factors 2
Populations Where Testing Should Not Be Conducted
Targeted tuberculin testing programs should be discouraged in low-risk populations. 1
- Persons at low risk for TB, for whom tuberculin testing is not generally indicated, require ≥15 mm of induration to be considered positive 1
- Testing should only be conducted among groups at high risk for developing active TB 1
Critical Distinction: Who DOES Need Treatment
To understand who does not need treatment, it's essential to recognize the high-risk groups who always require treatment regardless of age:
Strong recommendations for treatment (irrespective of age): 1
- People living with HIV (≥5 mm induration)
- Adult and child contacts of pulmonary TB cases (≥5 mm)
- Persons initiating anti-TNF-alpha treatment (≥5 mm)
- Patients receiving dialysis (≥10 mm)
- Patients preparing for organ or hematological transplantation (≥5 mm)
- Persons with silicosis (≥10 mm)
- Persons with abnormal chest radiographs showing fibrotic lesions consistent with prior TB (≥5 mm)
Conditional recommendations for treatment: 1
- Prisoners
- Healthcare workers
- Immigrants from high TB burden countries
- Homeless persons
- Illicit drug users
Common Pitfalls to Avoid
The most critical error is withholding treatment from high-risk patients over age 35 based solely on age. 2 The age cutoff applies only to low-risk individuals without additional risk factors. 2
Never confuse the absence of a recommendation for systematic testing with a contraindication to treatment. For diabetics, people with harmful alcohol use, smokers, and underweight individuals, the WHO does not recommend systematic screening programs, but if these individuals have other high-risk factors, they should still receive treatment. 1