Accuracy of lung and abdominal ultrasound for tuberculosis diagnosis: a prospective cohort study from India

Background: Point-of care ultrasound is considered to hold promise in tuberculosis (TB) screening. However, most available abdominal ultrasound data focuses on HIV-infected cohorts and for lung ultrasound (LUS) data is very sparse. We aimed to determine accuracy of lung and abdominal ultrasound in a cohort of presumed TB in a tertiary care hospital in India. Methods: Adult patients with presumed TB were enrolled prospectively and underwent a comprehensive ultrasound evaluation. Accuracy of individual and a predetermined combination of findings was determined against a TB reference standard (mycobacterial culture and PCR). Diagnostic potential of a multi-variable model combining clinical and ultrasound findings was explored using generalized mixed methods and random forest approach. (German trial registry DRKS00026636) Findings: We included 541 participants of whom 102 (19%) had TB and 1% had HIV. Focused assessment with sonography for HIV-associated tuberculosis (FASH) showed moderate sensitivity (51%, 95%-CI 41-60) and specificity (70%, 95%-CI 66-74). Small consolidations on LUS showed high sensitivity (98%, 95%-CI 93-99), but were unspecific (14%, 95%-CI 11-18). Exploratory LUS variations showed higher specificity (e.g., large apical consolidations: sensitivity 22%, specificity 86%). Predictive modelling for ultrasound and clinical variables revealed an Area Under the Curve of 0.79 in the receiving operator curve. Interpretation: Accuracy of ultrasound does not meet requirements of a stand-alone diagnostic or screening test. However, accuracy for some ultrasound findings is comparable with CXR. Additionally, ultrasound may aid disease severity assessment and microbiological sampling strategies. Research into alternative analyses (e.g., artificial intelligence) may enable wider applications. Funding: Grant TTU 02.911, German Center for Infection Research (Deutsches Zentrum fuer Infektionsforschung). ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Trial DRKS00026636 ### Funding Statement This work was supported by DZIF (German Center for Infectious Disease Research; Flexfund ID TTU 02.911). Research reported in this publication was supported by the National Institute of Allergy and Infectious Diseases of the US National Institutes of Health under award number U01AI152087. Ultrasound equipment was loaned at no cost by FujiFilm Sonosite. REPORT Neither party had any role in the study design, in data collection, data analysis, data interpretation, report writing or the decision to submit a manuscript for publication. No payment was received by any pharmaceutical company or other agency for the writing of this manuscript. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study was approved by CMC Vellore and University Heidelberg institutional review boards (CMC IRB ID 14342; Heidelberg ID S-314/2021). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Deidentified data will be made available upon reasonable request and provided in accordance to corresponding regulatory requirements.