Towards real-time urinalysis with holographic lens-free imaging

Urinalysis is an essential diagnostic tool in evaluating health and disease of the genitourinary tract. A urinalysis typically consists of dipstick testing, which can detect red blood cells, white blood cells, and bacteria, and microscopic evaluation of urine sediment after centrifugation, which further reveals other biomarkers such as crystals and casts. In the in-patient hospital setting, urinalysis is typically ordered after disease is suspected, drawing urine from the collection bag of a foley catheter and sending the sample to a core laboratory for analysis. To improve access to urine biomarkers, we propose a holographic lens free imaging (LFI) system that could allow automated bedside urine screening. LFI is uniquely suited for this task due to its low-cost, compact nature, and its ability to reconstruct large volumes from a single hologram without the depth-of-field tradeoff of conventional microscopy. Here, we build and demonstrate an LFI system capable of detecting important biomarkers such as E. Coli in PBS and red blood cells, casts, and crystals in urinalysis control phantoms. In the future, this compact system could be connected to the drainage tube of a patient's foley catheter to enable real-time screening of urine at the bedside.