I-Corps: Clinical Opportunities for Lens Free Holographic Urinalysis

Johns Hopkins University, Baltimore MD

Investigators

Abstract

The broader impact/commercial potential of this I-Corps project is the development of a device for improving the management of indwelling urinary catheters (IUC) in the hospital setting. Tens of millions of IUCs are inserted each year in the United States to relieve urinary retention, monitor urine output, and manage urination. However, a significant problem occurs with catheter-associated urinary tract infections (CA-UTI) - the most common nosocomial infection in the United States – which are caused by bacterial colonization of the urinary tract following placement of an IUC. A significant risk factor for CA-UTI is prolonged use of an IUC, and a majority of these cases are believed to be preventable through timely intervention. Currently, the standard of practice is to examine urine with the naked eye for problems and measure volume intermittently. Early detection of inflammatory biomarkers and bacterial load in the urinary system using the proposed technology may enable objective and timely removal of the IUC before the onset of CA-UTI. In addition to enabling the development of evidence-based triggers for catheter removal, real-time monitoring of urine flow has the potential to increase fluid management precision and detect acute changes. This I-Corps project is based on the development of a lens-free imaging device capable of continuous, non-invasive analysis of urine for measuring clinical biomarkers to detect early signs of catheter-associated urinary tract infections (CA-UTI). The proposed device sits in-line between an indwelling urinary catheter (IUC) and an attached urine drainage bag, providing real-time urinalysis at the bedside. Lens-free digital holography is used to acquire holograms of the urine as it flows through the device. A 3D sparse phase recovery reconstruction algorithm transforms single raw 2D hologram images into reconstructed 3D volumes. Particulates in each 3D volume are classified and quantified for reporting clinically relevant information including bacteria colony forming units (CFUs), white blood cell count, and the presence of red blood cell casts. A benchtop prototype system has been validated using human urine with known additions of red and white blood cells and/or E. coli bacteria. Measurements made with the benchtop system were compared with measurements from conventional methods, and the system was confirmed to be sensitive to concentrations several orders of magnitude above and below thresholds of pyuria, hematuria, and bacterial CFUs used for the diagnosis of UTIs. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.