Optimizing pathological diagnosis of tuberculosis: qPCR outperforms acid-fast staining in formalin-fixed paraffin-embedded tissues and enables resistance profiling

Background and Objective: (MTB) in formalin-fixed paraffin-embedded (FFPE) tissues remains a significant challenge in routine pathological practice. This study aimed to evaluate the performance of the first National Medical Products Administration (NMPA)-approved quantitative polymerase chain reaction (qPCR) kit specifically optimized for FFPE tissues. We compared its efficacy with acid-fast bacilli (AFB) staining for MTB detection, while simultaneously assessing its utility for drug resistance profiling and non-tuberculous mycobacteria (NTM) identification in pathological diagnosis. Methods: = 16). Results: = 0.257), with the highest concordance observed in intestinal specimens (83.95%). Resistance was noted in 18.18% of cases, with 7.0% classified as multidrug-resistant tuberculosis (MDR-TB), peaking in fallopian tubes (33.33% drug-resistant TB (DR-TB), 16.67% MDR-TB). Among the 25 discordant cases, 16 successfully underwent NTM identification, revealing 4 (25.0%) cases of NTM infection. Conclusion: This study demonstrates that the qPCR kit approved by the NMPA and optimized for FFPE tissue samples exhibits high effectiveness in the pathological diagnosis of tuberculosis when culture methods are not feasible. Its performance significantly surpasses that of AFB staining. Using DNA extracted from a single FFPE tissue section, we established an integrated molecular testing strategy. This approach enables the sensitive detection of MTB through qPCR, demonstrating a higher detection rate compared to AFB staining in FFPE tissues. Furthermore, it facilitates subsequent drug resistance analysis and the differentiation of NTM species from the same DNA sample, thereby providing a practical and efficient solution for comprehensive pathological diagnosis.