Table 2.
Type, Distribution, and Result of Respiratory Specimens Positive on Smear Microscopy or Xpert MTB/RIF Assay (n = 11)
| Subject No. | Specimen | Smear Microscopy | Xpert | Culture |
|---|---|---|---|---|
| 004 | S S S | + + + | + + + | TB TB TB |
| 010 | S S S | + + + | + + + | TB TB TB |
| 020 | S S | + + | – – | NTM NTM |
| 036 | S S S | – + + | – + + | – TB TB |
| 109 | F F S | F F – | F F + | F F – |
| 115a | S S S | + – + | + – + | TB – TB |
| 161b | S S B | I + + | + + N | TB TB TB |
| 201b | B S S | + + I | N – – | NTM NTM NTM |
| 208 | S S S | + – – | – – – | NTM NTM NTM |
| 219 | S S | + – | + – | TB TB |
| 222 | T S | – + | N – | – – |
Abbreviations: +, positive result; –, negative result; B, bronchoalveolar lavage specimen (not run for Xpert testing); F, failed sputum induction (not run for smear microscopy, Xpert, or culture); I, indeterminate result; N, not performed; NTM, nontuberculous mycobacteria; S, sputum specimen (induced or expectorated); T, tracheal aspirate specimen (not run for Xpert testing); TB, Mycobacterium tuberculosis; Xpert, Xpert MTB/RIF assay.
a Subject 115 demonstrated rifampicin resistance on Xpert and was subsequently diagnosed with multidrug-resistant TB based on culture.
b Indeterminate smear microscopy result indicates 1–2 acid-fast bacilli per 300 fields. The laboratory protocol considers this result nonnegative and suggests repeat specimen collection.