Enhancing the Accuracy of Peripheral Pulmonary Tuberculosis Diagnosis: A Comparative Evaluation of CapitalBioTM Mycobacterium Nucleic Acid Detection Test and Mycobacterium tuberculosis Isothermal RNA Amplification Assay Using Endobronchial Ultrasonography with Guide Sheath.

Purpose: The diagnosis of tuberculosis located in the peripheral zone remains challenging and requires ultrasound bronchoscopy-guided maneuvers. We assessed the precision of CapitalBio^TM Mycobacterium nucleic acid detection test (CapitalBio MTB test) and Mycobacterium tuberculosis isothermal RNA amplification test (MTB-RNA) using endobronchial ultrasonography with a guide sheath (EBUS-GS) for peripheral pulmonary tuberculosis (PTB) and compared it with those of acid-fast bacilli (AFB) smear and MTB culture tests.

Patients and methods: This retrospective analysis included 287 patients suspected of peripheral pulmonary tuberculosis who underwent EBUS-GS examinations, medical examination results of AFB smears, MTB culture, CapitalBio MTB test, and MTB-RNA were analyzed. We evaluated the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the receiver operating characteristic curve (AUC), and its diagnostic accuracy for peripheral PTB was evaluated in comparison with the final clinical diagnosis.

Results: The overall sensitivity, specificity, PPV, NPV, and AUC of CapitalBio MTB test were 44.83%, 100.00%, 100.00%, 54.07%, and 0.72, respectively; those of MTB-RNA were 22.99%, 100.00%, 100.00%, 45.75%, and 0.61, respectively, and those for parallel test (CapitalBio MTB test or MTB-RNA) were 46.55%, 100.00%, 100.00%, 54.85%, and 0.73, respectively. These values for AFB smear were 9.2%, 97.35%, 84.21%, 41.04%, and 0.53, respectively, and those of MTB culture were 31.03%, 100.00%, 100.00%, 48.50%, and 0.69, respectively.

Conclusion: The CapitalBio MTB test showed the best diagnostic performance compared with AFB smear, MTB culture, and MTB-RNA assays and was similar to the parallel test (CapitalBio MTB test or MTB-RNA). The CapitalBio MTB test combined with EBUS-GS had satisfactory diagnostic accuracy for diagnosing peripheral PTB.