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2004;10:1713). Other reports do not support this recommendation (JAMA 2001;286: 2450).
M. tuberculosis.
TESTS TO DETECT LATENT AND ACTIVE TB:
Any patient with HIV infection and no prior record of a positive test or TB treatment should undergo diagnostic testing for latent TB with a tuberculin skin test (TST or PPD), or a IFN γ release assay (IGRAs) or both. The relative merits of these test methods in HIV-infected patients is unknown except that IGRAs are preferred in those previously given BCG (See pg ___). Patients with negative skin tests should be retested if the CD4 count increases to >200 cells/mm3 if the baseline test was performed at a CD4 count below that level. The test should be repeated annually in patients with risk for TB based on regional TB rates or sociodemographic factors. Patients with fibrotic changes on chest x-ray that are consistent with TB should receive INH prophylaxis regardless of TST results. Patients with positive tests should be evaluated for active TB, which should include a chest x-ray.
INDICATIONS FOR PROPHYLAXIS
- Positive skin test (≥ 5 mm induration) and no prior history of treatment for active or latent TB
- Negative skin test and exposure to close contact with pulmonary TB
- A history of untreated or inadequately treated TB
- Evidence of old fibrotic lesions on chest x-ray in patients without adequate prior treatment regardless of PPD/IGRA test after active TB is excluded
RISK (MMWR1998;47:RR-20): Positive test for latent TB (pos PPD with ≥5 mm induration or pos gamma interferon release assay) without prior prophylaxis or treatment, recent TB contact, or history of inadequately treated TB that healed (MMWR 2000;49[RR-6]). The risk of active TB in those with a positive TST or latent TB infection is magnified 7-80 fold by HIV co-infection (Lancet 2000;356:470; MMWR 2000;49[RR-6]). It also appears that active TB accelerates the rate of HIV progression (JAIDS 1998;19:361; BMJ 1995;311:1468; J Infect Dis 2004;190:869). HIV-infected persons who are close contacts of active TB cases should be evaluated to exclude active disease and should receive treatment for latent TB infection regardless of PPD results.
EFFICACY OF PROPHYLAXIS: The Cochrane Library review for TB prophylaxis in patients with AIDS showed an odds ratio (OR) for active TB of 0.38 in those with a positive PPD based on 11 trials that included 8,130 patients. Prophylaxis reduced active TB rates by 62%. Efficacy was similar for different recommended drug regimens (Cochrane Database Syst Rev 2004;D000171).
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