HueFertility Ovulation: A Smartphone-Enabled Quantification System for Urinary Luteinizing Hormone in a Lateral Flow Assay

Luteinizing hormone (LH) is a critical biomarker for ovulation prediction and reproductive health monitoring, yet most commercially available at-home LH tests rely on qualitative or semi-quantitative visual interpretation, limiting their clinical utility. We present HueFertility Ovulation, a smartphone-enabled quantitative LH measurement system comprising a lateral flow immunoassay dipstick and a mobile application that integrates proprietary color correction algorithms with a deep learning regression model to deliver objective LH concentration estimates from strip images captured under variable real-world conditions. Color correction using the HueCard reference system substantially reduced inter-image color variability, decreasing mean ΔE00 from 11.19 to 4.02 across diverse lighting environments. When evaluated against known LH concentrations in a separately acquired independent dataset, the regression model achieved R2=0.92 and a mean absolute percentage error (MAPE) of 17.4%. The experimental limits of blank, detection, and quantitation were 0.64, 3.18, and 10.00 mIU/mL, respectively. Multi-site precision testing demonstrated %CVs within 25% across three independent locations. At a per-test cost of $0.60 with no external hardware required, HueFertility offers a low-cost, accessible platform for quantitative LH monitoring, with utility in fertility planning, hormonal health tracking, and resource-limited settings. Ultimately, the study highlights the opportunity to extend the technology to other low-cost lateral flow tests and clinical chemistry applications.