8
Diagnosis
➤ 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).
➤ The panel suggests flexible bronchoscopic sampling, rather than
no bronchoscopic sampling, in adults with suspected pulmonary
TB from whom a respiratory sample cannot be obtained via
induced sputum (C-VL).
Remarks: In the committee members' clinical practices, bronchoalveolar lavage (BAL)
plus brushings alone are performed for most patients. However, for patients in whom a
rapid diagnosis is essential, transbronchial biopsy is also performed.
➤ The panel suggests that postbronchoscopy sputum specimens
be collected from all adults with suspected pulmonary TB who
undergo bronchoscopy (C-L).
Remarks: Postbronchoscopy sputum specimens are used to perform AFB smear
microscopy and mycobacterial cultures.
