Purpose: Previous studies have indicated that the development of severe adverse events is associated with linezolid peak concentration (C_max), but the factors affecting linezolid C_max and evidences on therapeutic drug monitoring to anticipate toxicity in drug-resistant tuberculosis (DR-TB) patients have not been clarified clearly. This study aimed to explore the factors influencing linezolid C_max and investigate the association between linezolid concentration and hematological toxicity. Patients and Methods: This study included patients with drug-resistant tuberculosis treated with linezolid from January 2022 to September 2023. We analyzed the factors affecting linezolid C_max using chi-squared and binary logistic regression. The diagnostic utility of linezolid C_max in predicting hematological toxicity was evaluated using receiver operating characteristic (ROC) analysis. Results: A total of 76 patients were enrolled in the study. 63.20% met the standard rates for linezolid C_max. Age (P=0.036), weight (P=0.0016), and creatinine clearance (P=0.0223) significantly correlated with the C_max. Hematological toxicity was observed in 46.05% (35/76) of patients, characterized by thrombocytopenia (31.58%, 24/76), anemia (6.58%, 5/76), and leukopenia (21.05%, 16/76). ROC curve analysis confirmed the predictive value of linezolid C_max for thrombocytopenia with an area under curve of 0.728. Conclusion: Suboptimal linezolid C_max was prevalent among patients with DR-TB, with age, weight, and renal function emerging as influential factors. Elevated linezolid C_max increases the risk of thrombocytopenia. Meticulous monitoring of linezolid C_max is imperative during anti-DR-TB therapy to tailor treatment and mitigate hematological toxicity.

To evaluate the diagnostic accuracy of tuberculosis RNA (TB-RNA) for the rapid diagnosis of bone and joint tuberculosis (BJTB). We conducted a retrospective study to evaluate the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC) of TB-RNA and acid-fast bacillus (AFB) smear against the final clinical diagnosis. A total of 268 patients were included. The overall sensitivity, specificity, PPV, NPV, and AUC of AFB smear for BJTB were 0.7%, 100.0%, 100.0%, 49.3%, and 0.50, respectively, whereas those of TB-RNA were 59.6%, 100.0%, 100.0%, 70.6%, and 0.80, respectively; for cases of confirmed (culture-positive) BJTB, these values were 82.8%, 99.4%, 99.7%, 89.2%, and 0.91, respectively. The diagnostic accuracy of TB-RNA in the rapid diagnosis of BJTB was relatively good, especially in culture-positive BJTB. The use of TB-RNA could be an effective technique for the rapid diagnosis of BJTB.