5
➤ The panel suggests performing a diagnostic nucleic acid
amplification test (NAAT), rather than not performing a NAAT, on
the initial respiratory specimen from patients suspected of having
pulmonary TB (C-L).
Remarks: In AFB smear-positive patients, a negative NAAT makes TB disease unlikely.
In AFB smear-negative patients with an intermediate to high level of suspicion for
disease, a positive NAAT can be used as presumptive evidence of TB disease, but a
negative NAAT cannot be used to exclude pulmonary TB. Appropriate NAAT include
the Hologic Amplified Mycobacteria Tuberculosis Direct (MTD) test (San Diego,
California) and the Cepheid Xpert MTB/RIF test (Sunnyvale, California).
➤ The panel recommends performing rapid molecular drug
susceptibility testing for rifampin with or without isoniazid using
the respiratory specimens of persons who are either AFB smear
positive or Hologic Amplified MTD positive and who meet one of
the following criteria (S-M):
• have been treated for tuberculosis in the past
• were born in or have lived for ≥1 year in a foreign country with at least a moderate
tuberculosis incidence (≥20 per 100,000) or a high primary multidrug-resistant
tuberculosis prevalence (≥2%)
• are contacts of patients with multidrug-resistant tuberculosis, or
• are HIV infected.
Remarks: This recommendation specifically addresses patients who are Hologic
Amplified MTD positive because the Hologic Amplified MTD NAAT only detects
TB and not drug resistance. It is not applicable to patients who are positive for types of
NAAT that detect drug resistance, including many line probe assays and Cepheid Xpert
MTB/RIF.
➤ The panel suggests mycobacterial culture of respiratory
specimens for all children suspected of having pulmonary TB
(C-M).
Remarks: In a low incidence setting like the United States, it is unlikely that a child
identified during a recent contact investigation of a close adult/adolescent contact with
contagious TB was, in fact, infected by a different individual with a strain with a
different susceptibility pattern. Therefore, under some circumstances, microbiological
confirmation may not be necessary for children with uncomplicated pulmonary TB
identified through a recent contact investigation if the source case has drug-susceptible
TB.
➤ The panel suggests sputum induction rather than flexible
bronchoscopic sampling as the initial respiratory sampling
method for adults with suspected pulmonary TB who are either
unable to expectorate sputum or whose expectorated sputum is
AFB smear microscopy negative (C-L).
S, strong ; C, conditional; H, high; M, moderate; L, low; VL, very low quality of evidence
