Table 4.
Summary of 9 cases with discordant mNGS and RT-PCR results.
| No. | Sample | RT-PCR (Ct) | mNGS (SMRNs) | Xpert (concentration) | Clinical diagnosis |
|---|---|---|---|---|---|
| 1 | BALF | + (22.00) | – | Extremely low | Pulmonary TB, after 6 months of ATT |
| 2 | BALF | + (23.82) | – | Extremely low | Pulmonary TB, after 3 months of ATT |
| 3 | BALF | + (22.12) | – | Extremely low | Previous history of TB |
| 4 | BALF | + (24.05) | – | – | Pulmonary TB |
| 5 | BALF | - (NoCt) | + (79) | Extremely low | Pulmonary TB |
| 6 | BALF | - (NoCt) | + (3) | Extremely low | Pulmonary TB |
| 7 | BALF | - (27.05) | + (7) | Extremely low | Pulmonary TB |
| 8 | BALF | - (28.60) | + (13) | Extremely low | Not applicable |
| 9 | Lymph node | - (NoCt) | + (2) | – | TP, TBP, after 2 weeks of ATT |
Ct, cycle threshold; SMRNs, strict mapped read numbers; BALF, bronchoalveolar lavage fluid; +, positive; -, negative; TB, tuberculosis; ATT, anti-tuberculous therapy; TP, tuberculous pleuritis; TBP, tuberculous pericarditis.
Sanger sequencing of the rpoB gene fragment was successfully performed on the residual sample from Case 7. BLAST analysis of the obtained sequence confirmed the presence of Mycobacterium tuberculosis DNA.