What is the recommended screening and treatment process for Tuberculosis (TB)?

Screening for Tuberculosis

All individuals at increased risk for TB should undergo baseline screening with an individual risk assessment, symptom evaluation, and testing with either interferon-gamma release assay (IGRA) or tuberculin skin test (TST), followed by chest radiography if testing is positive to distinguish latent TB infection (LTBI) from active TB disease. 1

Who Should Be Screened

High-Risk Populations Requiring Screening

• Close contacts of persons with active pulmonary TB (household members, frequent visitors) 1, 2
• Foreign-born persons from high TB burden countries (Africa, Asia, Eastern Europe, Latin America, Russia) 1, 2
• Healthcare personnel at baseline (preplacement) 1
• Persons living with HIV 1
• Patients initiating immunosuppressive therapy, including:
  • Anti-TNF biologics (infliximab, adalimumab, etanercept) 1, 3
  • Rituximab 3
  • Corticosteroids 1
• Patients preparing for organ or hematological transplantation 1
• Patients with chronic kidney disease or on dialysis 1
• Residents of congregate settings (correctional facilities, homeless shelters, long-term care facilities) 1
• Persons with diabetes mellitus, malignancies, hepatitis C, rheumatoid arthritis, or vitamin D deficiency 1

Low-Risk Populations

• Routine serial screening is NOT recommended for healthcare personnel in low-risk settings without known exposure 1
• Screening of low-risk individuals without specific risk factors is discouraged 1

Screening Process

Step 1: Individual Risk Assessment

• All persons should receive an individual TB risk assessment before testing to guide interpretation of results 1
• Risk assessment should identify: history of TB exposure, country of origin, living/working conditions, immunosuppressive conditions, and HIV status 1

Step 2: Symptom Evaluation

• Screen for TB symptoms including cough (any duration), fever, night sweats, weight loss, hemoptysis 1
• Symptom screening alone has only 51.8% sensitivity for detecting active TB and should not be used as the sole screening method 4

Step 3: Testing for TB Infection

• IGRA is preferred over TST, especially in:
  • Patients with prior BCG vaccination 1, 3
  • Patients already on immunosuppressive therapy 3
  • Situations where return for TST reading is unlikely 2
• Perform testing only in persons without documented prior LTBI or TB disease 1
• For asymptomatic persons at low risk with a positive initial test, perform a second confirmatory test (either IGRA or TST); consider infected only if both tests are positive 1

Step 4: Chest Radiography

• Obtain chest X-ray (frontal view sufficient) after positive IGRA or TST to distinguish latent TB from active disease 1
• Chest radiography has 62.4% sensitivity for detecting active TB when any abnormality is considered positive 4
• Combined symptom and CXR screening detects only 64% of all TB cases, missing substantial asymptomatic disease 4
• CT should be reserved for equivocal chest X-ray findings or when knowledge of latent TB abnormalities may inform future care (e.g., transplant candidates, biologic therapy) 1

Step 5: Microbiological Confirmation

• If active TB is suspected (symptoms or abnormal CXR), obtain sputum for acid-fast bacilli smear and culture before starting treatment 1, 5
• Xpert MTB/RIF Ultra testing should be performed for rapid diagnosis and rifampin resistance detection 4

Post-Exposure Screening

After Known TB Exposure

• Perform symptom evaluation immediately when exposure is recognized 1
• Test with IGRA or TST at the time exposure is identified 1
• If initial test is negative, repeat testing 8-10 weeks after last exposure using the same test type as the initial test 1
• Persons with documented prior LTBI or TB disease do not need repeat testing after exposure, but should have clinical evaluation if TB disease is suspected 1

Treatment Following Positive Screening

For Latent TB Infection (LTBI)

Treatment is strongly encouraged for all persons with untreated LTBI, unless medically contraindicated. 1

Preferred regimens:

• Isoniazid plus rifapentine once weekly for 3 months (directly observed therapy) 5, 6
• Isoniazid plus rifampin daily for 3-4 months 3, 6
• Rifampin alone daily for 4 months 3, 6
• Isoniazid alone for 9 months (alternative, longer duration) 3, 5

For patients starting biologics (including rituximab):

• Initiate or resume biologic therapy after at least 1 month of LTBI treatment 1, 3

For Active TB Disease

Treatment requires a multi-drug regimen:

• Intensive phase (8 weeks): Isoniazid, rifampin, pyrazinamide, and ethambutol 5, 7, 6
• Continuation phase (18+ weeks): Isoniazid and rifampin, adjusted based on susceptibility testing 5, 7, 6
• All suspected and confirmed TB cases must be reported to local or state health departments 6
• Consultation with a TB expert is necessary for drug-resistant TB 6, 8

Ongoing Monitoring

• Annual TB screening should be considered for persons with ongoing TB exposure risk (healthcare workers in high-risk areas, frequent travelers to endemic regions) 1, 3
• Persons with untreated LTBI should receive annual symptom screening 1
• Do not repeat IGRA or TST in persons who previously tested positive; instead, monitor for clinical signs and symptoms of active TB 3

Important Caveats

• Asymptomatic TB represents 82% of TB cases among household contacts and is frequently missed by symptom and CXR screening alone 4
• Chest radiography in asymptomatic persons with positive TB tests has negligible yield for changing management in the absence of clinical symptoms 1
• Universal sputum microbiological testing may be necessary in high-risk populations (e.g., household contacts) to detect pauci-bacillary asymptomatic disease 4
• Pyridoxine (vitamin B6) supplementation is recommended with isoniazid therapy in malnourished patients, alcoholics, and diabetics 5