Quantification of sweat urea in diabetes using electro-optical technique

To develop a device for quantifying sweats urea concentration.

The proposed optical device uses light source, light sensor with time and intensity controlled operation. Sweat samples are collected from a group of volunteers belonging to control and diabetes. After sedimentation and suitable pre-processing, sweat samples are irradiated by primary colour light sources operated sequentially. Reflected light intensity is used to compute the sweat urea concentration. At first the test is performed using aqueous solution with known urea concentration. After ascertaining the correctness of the device, the same test procedure is repeated for sweat samples collected from 90 volunteers (30 per group) belonging to controls, type II diabetes less than 5 years and type II diabetes for more than 5 years.

Computed urea concentration when compared with standard lab techniques like UV-visible absorption spectroscopy and colorimeter, a correlation of 98% with error less than 3% is achieved. The results also demonstrate an elevation in sweat urea level with years of diabetes, in spite of the serum urea level being within limits. We extended the study on a few kidney disease subjects and observed the influence of blood glucose on urea.

Diabetic kidney disease is one result of prolonged elevation in blood glucose levels. When insulin secretion reduces, the serum urea level increases and vice versa is also true. Hence, monitoring urea level in blood is important in diabetic subjects. Any change in serum urea will have an impact on sweat urea concentration. Therefore, the proposed device can be used to measure sweat urea periodically, so that any change can be observed at an early stage and diabetic nephropathy could be prevented at large.