Accuracy of heart rate, pulse oxygen saturation, and blood pressure using a non-contact photoplethysmography-based mobile application: A potential tool for wellness monitoring

Abstract

Background: Photoplethysmography (PPG) is an effective non-contact technique for measuring vital signs. This report aims to evaluate whether a non-contact PPG-based mobile application supports an appropriate level of accuracy in monitoring SpO₂, HR, and BP, compared against clinically approved medical devices.

Methods: Adult volunteers (≥18 years, both male and female) were consecutively enrolled from September to November 2024. Remote photoplethysmography (rPPG) for data collection involves recording subjects' faces using the front camera of mobile devices for ∼1.5 minutes. Simultaneously, vital signs will be continuously collected for about 1.5 minutes using the reference devices alongside data collected via the comestai application.

Results: A total of 562 participants (279 F/283 M) were enrolled. The app demonstrated excellent accuracy for HR (MAE 2.96, MAPE 4.14, and accuracy 99.1%) and SpO₂ (MAE 2.10, MAPE 2.12, and accuracy 93.4%; no participants with SpO₂ < 95% were not present). Results for systolic blood pressure (SBP) (MAE 14.24, MAPE 11.33, and accuracy 61.3%) and diastolic blood pressure (DBP) (MAE 9.83, MAPE 11.66, and accuracy 56.0%) were more moderate. The ROC curve analysis confirmed the app's robust detection capabilities for HR (AUC 0.976) and SpO₂ (AUC 0.947), while showing fair performance for SBP (AUC 0.668) and weaker results for DBP (AUC 0.578). Bland-Altman plots revealed mean differences of -0.83 for HR, 1.84 for SpO₂, -4.49 for SBP, and 2.54 for DBP compared to conventional methods.

Conclusions: The non-contact PPG-based mobile app holds promise as an accessible, user-friendly tool for wellness monitoring. Solutions like comestai.app present both new opportunities and challenges in the wellness sector, emphasizing the need for continued research in this field.

Keywords: Non-contact photoplethysmography; mobile application; monitoring; vital signs; wellness.

Figure 1.

Video frame captured by comestai.app.

Figure 2.

Bland-Altman plots of systolic and diastolic pressure (Panels a and b), heart rate (Panel c), and oxygen saturation (Panel c), measures made using the mobile application and the conventional method. For each one, the horizontal line at the center of the mean difference between the two methods is plotted and the other two horizontal lines represent the limits of agreement, calculated as the $\mathrm{mean}\pm 1.96*\mathrm{standard}\mathrm{deviation}\mathrm{of}\mathrm{the}\mathrm{differences}$ that show the interval in which 95% of the differences between the two measurement methods fall.