New microfluidic device brings affordable kidney testing to care

New microfluidic device brings affordable kidney testing to care

Chronic kidney disease (CKD) affects over 800 million people worldwide and is often diagnosed too late to receive effective intervention. Early detection depends on accurate measurement of biomarkers such as creatinine and urinary albumin-to-creatinine ratio (UACR). While urine testing is non-invasive and informative, standard methods are time-consuming, costly and require specialized facilities. Existing point-of-care devices provide convenience, but remain prohibitively expensive or technically complex for many users. Therefore, there is an urgent need for a robust, affordable, and user-friendly platform to measure urinary creatinine with clinical precision. Because of these challenges, new approaches are needed to develop accessible diagnostic tools for CKD screening and surveillance.

Researchers at the University of Manitoba, in collaboration with clinical and technical partners, have developed a low-cost, passive microfluidic device for urine creatinine testing. Published (doi: 10.1038/s41378-025-00880-z) on April 2, 2025 inMicrosystems & NanoengineeringThe study describes the design, manufacturing and validation of the “UCR chip”. This device uses a color-based JAFFE reaction and a pressure-balanced flow system to provide fast, stable measurements. By eliminating the need for external pumps or electricity, the UCR chip paves the way for affordable, decentralized kidney function testing.

The UCR-CHIP integrates two key innovations: a Passive 2-Phase Pressure Compensation System (2-PPC) and a microfluidic channel network designed for a precise 1:5 mixing ratio between urine and reagent. This setup ensures consistent chemical reactions and rapid stabilization of the colorimetric signal. Using the Jaffe reaction, which produces an orange complex when creatinine interacts with picric acid under alkaline conditions, the chip enables quantifiable optical readings via a USB microscope platform. Signal stabilization is achieved within 7 minutes and the ChIP maintains detection stability over 30 minutes - a significant improvement over traditional assays. Technical validation demonstrated a dynamic linear detection range of up to 40 mm and a low detection limit of 0.521 mm, covering the entire clinical range. Compared to commercial point-of-care systems, the UCR chip demonstrated comparable or better accuracy and less intervention by artificial urine matrices. In addition, the optimized window for lenticular observation windows with a flow duration improves signal uniformity and shortens filling time. The device is manufactured using dry film lithography for high precision and is both scalable and reproducible. Together, these features make the UCR chip an attractive platform for portable diagnostics.

Our goal was to create a diagnostic tool that was as easy to use as a glucose test strip, but with the accuracy of a laboratory-based creatinine assay. The UCR chip meets this need by combining microfluidic precision with user-friendly design. It has the potential to change the way we detect and treat kidney disease, particularly in under-resourced settings. “

Dr. Francis Lin, co-senior author

Dr. Lin highlighted the device's affordability and scalability as important advantages for widespread public health deployment.

Beyond CKD screening, the UCR chip provides a broader platform for real-time health monitoring in various scenarios, from sports medicine to maternal care and drug testing. The researchers envision integrating this chip with a similar urinary albumin microfluidic device for simultaneous measurement of UACR, a crucial marker of kidney damage. The design also lends itself to future upgrades using enzymatic assays or fluorescence-based detection for improved specificity. With its compact, cost-effective and electrically-free format, the UCR chip represents an important step towards equitable point-of-care diagnostics tailored to both clinical and home environments.

Sources: