(130b) An Accurate, Precise, and Affordable Light Emitting Diode Spectrophotometer with a Raspberry Pi User Interface for Diabetes Testing in Honduras

The spectrophotometric determinations of glucose in blood serum and urine are commonly used for diabetes testing in Honduras. However, the high cost of spectrophotometers often limits access to diabetes testing in this and other low-income countries. To make this testing more accessible, a highly affordable light-emitting diode (LED) spectrophotometer was designed, built, and tested for 3 years using best engineering practices and state-of-the-art electrical components. In addition, this LED spectrophotometer used a Raspberry Pi credit-card sized computer for a user interface, and for data processing and storage. The cost and performance of this LED spectrophotometer/Raspberry Pi system was compared against 3 common commercial spectrophotometers. More specifically, the performance of these instruments was evaluated from the upper limits of linear range, upper limits of operational range, calibration sensitivities, R² values, estimated limits of detection, and percent calibration check standard recoveries for the determination of glucose using o-toluidine in glacial acetic acid. The parts for our LED spectrophotometer/Raspberry Pi system costs $168 United States dollars. The 3 commercial spectrophotometers ranged in price from $2,382 to $3,382. Our results suggest that the LED spectrophotometer/ Raspberry Pi system has upper limits of linear range, upper limits of operational range, calibration sensitivities, R² values, estimated limits of detection, and percent calibration check standard recoveries that are generally comparable to those of the 3 commercial spectrophotometers used in this study. In conclusion, this LED spectrophotometer/Raspberry Pi system is highly affordable and could be used to make diabetes testing in Honduras and other low-income countries more widely accessible.