When is treatment of latent tuberculosis infection (LTBI) recommended?

When to Treat Latent Tuberculosis Infection (LTBI)

Treatment of LTBI is required for individuals at high risk of progression to active TB disease, as treatment reduces the lifetime risk of reactivation from 5-15% to near-zero, but active TB disease must first be definitively excluded through chest radiography and clinical assessment. 1

Mandatory Pre-Treatment Requirement

Before initiating any LTBI treatment, you must rule out active TB disease through: 1, 2

• History and physical examination assessing for TB symptoms (cough, fever, night sweats, weight loss) 1
• Mandatory chest radiography to exclude active pulmonary TB 1, 2
• Sputum samples for acid-fast bacilli smear and culture if symptoms present or abnormal chest X-ray 1

High-Priority Groups Requiring Treatment

Highest Risk (Treat Immediately After Excluding Active TB)

HIV-infected persons must receive treatment given their 5-10% annual reactivation risk (compared to 5-15% lifetime risk in HIV-negative individuals): 1, 2

• TST ≥5 mm is considered positive in this population 1
• Use 9 months of isoniazid rather than 6 months 1
• Baseline and ongoing laboratory monitoring required 1

Recent contacts of infectious pulmonary TB cases should be treated immediately after active TB is excluded, regardless of test results 1, 2

Patients initiating immunosuppressive therapy: 1, 2

• Anti-TNF biologics or other biologics 1
• Organ or hematological transplantation preparation 1
• High-dose corticosteroids 2

Other High-Risk Groups Requiring Treatment

Children <5 years old with positive testing (TST ≥10 mm for those <4 years or exposed to high-risk adults): 1, 2

• Use isoniazid for 9 months as the only recommended regimen for children 1, 2

Radiographic evidence of prior untreated TB (fibrotic changes consistent with old TB): 1, 2

• Use 9 months of isoniazid rather than 6 months 1

Medical conditions with elevated risk: 1

• Dialysis for chronic renal failure 1
• Silicosis 1

Moderate-Risk Groups (Consider Treatment When Multiple Risk Factors Present)

Treatment should be considered when 2 or more of the following risk factors are present: 3

• Oral or inhaled corticosteroids 3
• Other immunosuppressants 3
• Diabetes 3
• Being underweight 3
• Smoking 3
• Gastrectomy 3

Special Populations

Pregnant women at high risk (HIV-infected or recent infection) should receive LTBI treatment without delaying for the first trimester 1, 2

Healthcare workers with PPD ≥10 mm should receive treatment regardless of age, as they face ongoing TB exposure risk 4

Critical Pitfalls to Avoid

• Never treat LTBI without first excluding active TB disease through proper evaluation and chest radiography 1, 2
• Do not use targeted testing in low-risk populations—testing should only be conducted among high-risk groups 2
• Do not withhold treatment based on age alone in high-risk individuals with ongoing exposure 2, 4
• Avoid the rifampin-pyrazinamide regimen routinely due to unacceptable hepatotoxicity rates 1, 2

Treatment Decision Algorithm

1. Identify if patient belongs to high-risk group (see categories above) 1, 2
2. Perform mandatory chest radiography and symptom assessment to exclude active TB 1, 2
3. If active TB excluded and patient is high-risk, initiate treatment with appropriate regimen 1
4. For moderate-risk patients, treat only if ≥2 risk factors present 3
5. Establish monthly clinical monitoring for adherence, adverse reactions, and hepatotoxicity symptoms 1