Smartphone Based DTx Vital Signs and Blood Glucose Screening - AI Verified.

Photoplethysmography (PPG) is a non-invasive optical technique that detects blood volume changes in the microvascular tissue bed beneath the skin. Widely used in pulse oximeters to monitor a subject’s heartrate and peripheral oxygen saturation (SpO2), PPG relies on the fact that arterial blood displays different optical absorption with respect to other tissue components in certain light wavelengths. By emitting light through the skin layers and measuring the amount of light propagating in the tissue, we can obtain a PPG signal that reflects blood volume changes over time. The PPG-waveform can further be used to calculate physiological variables such as heartrate, respiratory rate, SpO2 and blood pressure. As well as use in medical applications, contact-based PPG has been adapted for use in some consumer-oriented wearable devices.