II. Labs
- IFN-Gamma Release Assay (IGRA, Quantiferon-TB)
- Tuberculin Skin Test (TST, PPD)
III. Precautions
- Patients with high suspicion for Active Tuberculosis require induced Sputum and other direct testing for organism
- Tuberculosis Screening is used only to identify Latent Tuberculosis
IV. Indications: Tuberculosis Screening
- Low risk patients
- Routine, universal screening not recommended
- Screen only if symptoms suggest possible Tuberculosis without meeting risk factors below
- High risk patients
V. Indications: Lab test selection (IGRA vs TST)
- Cases in which IGRA is preferred over TST
- Unreliable follow-up for TST testing (homeless patients, Illicit Drug use)
- No healthcare worker available to read PPD In 2-3 days
- Patients with prior BCG vaccine
- Live Virus Vaccine in prior 4 weeks (False Negative TST risk)
- Cost difference between TST ($50-100) and IGRA ($150-225) is not an issue for patient
- IGRA is overall a better test (more reproducible and accurate regardless of BCG)
- Cases in which TST is preferred over IGRA
- Children under age 5 years old
- Low resource environments with cost limitations or lack of lab facility
- Cases in which either IGRA or TST are acceptable
- Periodic screening for occupational exposure to Tuberculosis
- Recent exposure to person with known or suspected Active Tuberculosis
- Cases in which both tests might be considered together (if equivocal or mixed results expected)
- Indeterminate initial testing
- Higher risk population for exposure or progression but negative initial testing
- Immunocompromised
- Child under age 5 years
- Clinical suspicion for Active Tuberculosis based on history, exam, imaging but with negative initial testing
- Positive initial tests but confirmatory testing is desired by either the patient or provider
- Suspicion of False Positive, or low risk for progression