Nanoparticle capture of urinary lipoarabinomannan for diagnosing childhood tuberculosis

Abstract Urinary assays detecting lipoarabinomannan (LAM) as a diagnostic test for tuberculosis (TB) have limited sensitivity in pediatric populations. We aimed to evaluate a urine processing step using the Ceres TB-Nanotrap to concentrate available LAM antigens and augment LAM detection in urine using the Alere lateral flow assay (LF-LAM). This case-control study recruited children with TB and non-TB controls aged 1-18 years from outpatient clinics. The LF-LAM test was performed before and after concentrating 5mL of urine with 400uL of magnetic TB-Nanotrap particles. Band intensity was measured via visual grading and digital quantification. Urine LAM sensitivity by visual grading was 4.5% (95% Confidence Interval [CI]: 0.3 – 18.5) pre-concentration and 50.0% (95% CI 30.0 – 70.0) post-concentration. Sensitivity by digital quantification was 0.0% (95% CI 0.0 – 15.4) pre-concentration and 63.9% (95% CI 42.8 – 81.4) post-concentration. Specificity was high with both methods (visual grading 90.0% [62.8 – 99.4] pre-concentration, 90.0% [62.8 – 99.4] post-concentration; digital analysis 80.0% [44.4 – 97.5], 90.0% [62.8 – 99.4] respectively). For cases, digital analysis showed an increase in median LF-LAM band intensity from 0.0 arbitrary units (AU) (IQR 0.00 – 32.5) in unconcentrated samples to 98.4 AU (IQR 34.9 – 212.2) in concentrated samples. Concentration with TB-Nanotrap greatly increased sensitivity of urine LAM detection without change in specificity. Digital quantitative analysis further increased sensitivity. Use of TB-Nanotrap and digital quantitative analysis of urine LAM improved the diagnostic accuracy of the LF-LAM assay in this pediatric population and should be validated in larger studies. Competing Interest Statement The authors have declared no competing interest. Funding Statement This work was funded by the University of Virginia Global Infectious Disease Institute and the National Research Program for Universities (NRPU), supported by Higher Education Commission (HEC) Pakistan. Award No: 5213/Sindh/NRPU/R&D/HEC/2026. This work was also supported by NIH T32 AI007044. 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: Ethical Review Committee at Aga Khan University gave ethical approval for this work (AKU ERC# 2924 and 019-0294-2363) The Institutional Review Board of Civil Hospital Karachi & Dow University of Health Sciences Karachi (IRB #450) gave ethical approval for this work The Institutional Review Board of University of Virginia (IRB-HSR# 17239) gave ethical approval for this work. Parents/caregivers of eligible children underwent the informed consent process and provided written parental permission for participation. 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 Data Availability All data produced in the present study are available upon reasonable request to the authors