A smear test aiding with an automated slide reader acquires equivalent sensitivity to MGIT960 culture in pulmonary tuberculosis diagnosis

Smear microscopy remains widely used for tuberculosis (TB) diagnosis due to its rapid turnaround and low cost, despite its relatively low sensitivity. With the advent of molecular tests, there is growing debate on whether the smear test remains relevant in clinical settings. An artificial intelligence (AI)-aided automated smear slide reader system (Zopomed, Zhengzhou, China) was evaluated at Beijing Chest Hospital. Sputum samples from suspected TB patients were used to prepare both Ziehl–Neelsen (ZN) and auramine O-stained slides. These were scanned by the automated reader under predefined field-of-view settings. Manual light-emitting diode fluorescence microscopy (for auramine O slides), MGIT960 culture, and Xpert MTB/RIF assay served as reference standards. Among 352 clinically confirmed TB patients, the detection rates were 18.75% by manual microscopy, 20.74% by automated ZN (1,000 fields), 32.67% by automated auramine O (300 fields), 30.68% by MGIT960 culture, and 42.05% by Xpert. Expanding the field of view significantly enhanced detection rates for both staining methods, with auramine O staining consistently outperforming ZN. The automated auramine O method (300 fields) identified 78.70% of culture-positive and 66.89% of Xpert-positive TB cases. All methods maintained specificities exceeding 99% when tested on 158 patients with non-mycobacterial pulmonary diseases. AI-aided auramine O smear testing represents a sensitive, rapid, and cost-effective approach to TB diagnosis. With the one-time investment in the automated system, this technique achieves sensitivity comparable to MGIT960 culture, offering a practical diagnostic solution for high-throughput clinical laboratories and resource-limited settings.

IMPORTANCE

This study demonstrated that an AI-aided automated smear microscopy system, when used with auramine O-stained slides scanning 300 fields, achieves a sensitivity comparable to MGIT960 culture, while offering the advantages of rapid, same-day results and significant cost-effectiveness; this one-time investment in equipment, which is compatible with routine staining protocols, provides a highly practical and scalable solution to enhance tuberculosis diagnosis in both high-throughput laboratories and resource-limited settings.