Utility of a Clinical Scoring System (Bandim TB Score and Karnofsky Performance Score) to Assess Mycobacterial Burden in Terms of Cartridge-Based Nucleic Acid Amplification Test (CBNAAT) Cycle Threshold Values Among Pulmonary TB Patients

Krishna Sarkar; Bineeta Kashyap; Sharanya Lnu; Rajnish K Avasthi; Ashwani Khanna

doi:10.7759/cureus.50976

Utility of a Clinical Scoring System (Bandim TB Score and Karnofsky Performance Score) to Assess Mycobacterial Burden in Terms of Cartridge-Based Nucleic Acid Amplification Test (CBNAAT) Cycle Threshold Values Among Pulmonary TB Patients

Cureus. 2023 Dec 22;15(12):e50976. doi: 10.7759/cureus.50976. eCollection 2023 Dec.

Authors

Krishna Sarkar¹, Bineeta Kashyap¹, Sharanya Lnu², Rajnish K Avasthi³, Ashwani Khanna⁴

Affiliations

¹ Department of Microbiology, University College of Medical Sciences, Delhi, IND.
² Medicine, Lady Hardinge Medical College, Delhi, IND.
³ Department of Medicine, University College of Medical Sciences, Delhi, IND.
⁴ Pulmonary Medicine, Lok Nayak Hospital, Delhi, IND.

Abstract

Aim: Tuberculosis (TB) continues to be a global public health problem. Physicians fail to clearly interpret cycle threshold (Ct) values as a measure of mycobacterial burden due to the paucity of literature correlating Ct values with the clinical scoring. This study aims to correlate the clinical scoring parameters (Bandim TB score and Karnofsky Performance score (KPS)) with Ct values obtained by Cartridge-Based Nucleic Acid Amplification Test (CBNAAT).

Materials and methods: The study spanned from November 2019 to October 2021, during which a total of 40 cases were recruited. These cases were identified as pulmonary TB patients based on Ziehl-Neelsen staining for acid-fast bacilli and/or the GeneXpert MTB/RIF assay. Bandim TB scores and KPSs were recorded using standardized questionnaires.

Results: There was a strong negative correlation between Bandim TB score and Ct value (mean), and this correlation was statistically significant (rho = -0.82, p < 0.001). There was a moderate positive correlation between KPS and Ct value (mean), and this correlation was statistically significant (rho = 0.57, p < 0.001).

Conclusion: No literature has compared Bandim TB score and KPS with the Ct values obtained by CBNAAT for pulmonary TB. Thus, the knowledge on the proper utilization of CBNAAT cycle threshold values and its correlation with clinical scoring parameters will help clinicians in the early identification and prompt initiation of appropriate treatment.

Keywords: active pulmonary tuberculosis; cartridge-based nucleic acid amplification test (cbnaat); clinical features; genexpert mycobacterium tuberculosis/rifampin (mtb/rif) assay; infectious disease diagnosis.