Y Tan1, B Su1, X Cai1, P Guan1, X Liu1, P Ma1, H Zhou1, J Liu2, Y Pang3. 1. Department of Clinical Laboratory, Guangzhou Chest Hospital, State Key Laboratory of Respiratory Disease, Guangzhou, Guangdong Province, China. 2. Department of Clinical Laboratory, Guangzhou Chest Hospital, State Key Laboratory of Respiratory Disease, Guangzhou, Guangdong Province, China. Electronic address: Ljxer64@qq.com. 3. National Clinical Laboratory on Tuberculosis, Beijing Key Laboratory on Drug-resistant Tuberculosis Research, Beijing Chest Hospital, Beijing Tuberculosis and Thoracic Tumour Institute, Beijing, China. Electronic address: pangyupound@163.com.
Abstract
OBJECTIVES: TB-EASM (Howsome, Shanghai, China), an automated system combining smear preparation, staining and microscopy in a single platform, was evaluated for tuberculosis (TB) diagnosis in a high disease-burden setting. METHODS: Sputum samples from individuals with pulmonary TB were processed in parallel using conventional manual smear microscopy (MS), TB-EASM, liquid culture and GeneXpert. Method sensitivity and specificity were compared with Mycobacterium tuberculosis detection by mycobacteria growth indicator tube (MGIT) and/or GeneXpert MTB/RIF. RESULTS: Of 524 samples, 496 met evaluation criteria for study inclusion. The proportion of M. tuberculosis detected by TB-EASM was 28.2% (150/496), significantly higher than for MS (111/496, 21.2%, p 0.01) and comparable to the rate for MGIT (163/496, 32.9%, p > 0.05). For 190 M. tuberculosis-positive cases identified using MGIT and/or GeneXpert MTB/RIF, the reference standard detection methods, TB-EASM detected 140 positive cases, for an overall sensitivity rate of 73.7% (140/190, 95% CI 67.4-79.9), which was significantly higher than for MS (105/190, 55.3%, 95% CI 48.2-62.3, p < 0.01). Specificities were 96.7% (296/306, 95% CI 94.7-98.7) for TB-EASM and 98.0% (300/306, 95% CI 96.5-99.6) for MS. CONCLUSION: TB-EASM outperformed conventional MS for M. tuberculosis detection in sputum specimens.
OBJECTIVES: TB-EASM (Howsome, Shanghai, China), an automated system combining smear preparation, staining and microscopy in a single platform, was evaluated for tuberculosis (TB) diagnosis in a high disease-burden setting. METHODS: Sputum samples from individuals with pulmonary TB were processed in parallel using conventional manual smear microscopy (MS), TB-EASM, liquid culture and GeneXpert. Method sensitivity and specificity were compared with Mycobacterium tuberculosis detection by mycobacteria growth indicator tube (MGIT) and/or GeneXpert MTB/RIF. RESULTS: Of 524 samples, 496 met evaluation criteria for study inclusion. The proportion of M. tuberculosis detected by TB-EASM was 28.2% (150/496), significantly higher than for MS (111/496, 21.2%, p 0.01) and comparable to the rate for MGIT (163/496, 32.9%, p > 0.05). For 190 M. tuberculosis-positive cases identified using MGIT and/or GeneXpert MTB/RIF, the reference standard detection methods, TB-EASM detected 140 positive cases, for an overall sensitivity rate of 73.7% (140/190, 95% CI 67.4-79.9), which was significantly higher than for MS (105/190, 55.3%, 95% CI 48.2-62.3, p < 0.01). Specificities were 96.7% (296/306, 95% CI 94.7-98.7) for TB-EASM and 98.0% (300/306, 95% CI 96.5-99.6) for MS. CONCLUSION: TB-EASM outperformed conventional MS for M. tuberculosis detection in sputum specimens.