Development of Smartphone-Based Lateral Flow Device for the Quantification of LH and E3G Hormones

Hormone levels of urinary luteinizing hormone (LH) and Estrone-3-gluconoride (E3G) are key indicators to control reproductive health conditions of women. An “Inito” device is developed for the lateral flow measurement and is coupled to a smartphone to predict the fertile window by providing a precise estimation of the concentration of these hormones. The image acquisition and data analysis software has been developed on android platform. Lateral flow-based test strips are inserted into the Inito device and their images are captured and processed using smartphone yielding optical densities representing the concentrations of analytes. A multi-scale algorithm was developed to detect the device and eliminate the variations in resolution and aspect ratio due to smartphone variability. It also provides automatic focus point and appropriate exposure adjustment. Concentration of LH and E3G were quantified by locating and segmenting the respective hormonal lines. The study was validated using a standard clinical lateral flow assay reader. The Inito reader yielded a linear correlation of R2 > 0.99 suggesting a high degree of agreement with the gold standard. In addition, inter-phone repeatability of the Inito yielded very good correlation. The proposed Inito device can be very useful in point of care (PoC) settings.