qPCR shows higher MTB detection rate than AFB staining in granulomatous inflammation tissues

This cohort study evaluated the diagnostic performance of qPCR versus acid-fast bacilli (AFB) staining for Mycobacterium tuberculosis (MTB) detection in formalin-fixed paraffin-embedded (FFPE) tissues. The study included 1,050 patients with granulomatous inflammation suggestive of tuberculosis (median age 52 years, 43.71% males) in routine pathological practice. The intervention was qPCR using the first NMPA-approved kit for FFPE tissues, compared to standard AFB staining.

qPCR demonstrated a significantly higher positive rate for MTB detection at 63.43% compared to 26.29% for AFB staining (p < 0.05, exact p-value not reported). Among 143 qPCR-positive samples (Ct ≤ 35), 16 cases of non-tuberculous mycobacteria (NTM) were identified. Secondary outcomes included drug resistance profiling and NTM identification, but detailed results for these endpoints are not reported in the available text.

Safety and tolerability data were not reported. The study has important limitations, most notably that the study text is truncated and full results and limitations are not reported. Funding sources and conflicts of interest were also not reported.

This study provides preliminary evidence on the performance of the first NMPA-approved qPCR kit for FFPE tissues in detecting MTB. The findings suggest qPCR may offer higher detection rates than AFB staining in this specific tissue type, but clinicians should await full publication of results, including drug resistance profiling data, before making practice changes. The evidence does not support conclusions about clinical outcomes beyond diagnostic accuracy.