Validation of Remote Photoplethysmography for Non-Invasive Estimation of Blood Glucose and HbA1c

Validation of Remote Photoplethysmography for Non-Invasive Estimation of Blood Glucose and HbA1c in a Community-Based Population in Jakarta

The goal of this observational study is to evaluate whether a non-invasive facial scan technology using remote photoplethysmography (rPPG) can accurately estimate blood glucose and HbA1c levels in adults living in the community in Jakarta. The study focuses on adults aged 18 years and older, including individuals with or without diabetes.

The main questions it aims to answer are:

1. Can rPPG-based facial scan estimates of blood glucose and HbA1c match results from standard laboratory blood tests?
2. How well can rPPG identify individuals with high blood sugar or diabetes risk based on established clinical cut-off values?

Researchers will compare results from the rPPG facial scan with standard laboratory measurements of fasting blood glucose and HbA1c to determine how accurate and reliable the technology is for screening purposes.

Participants will:

1. Provide basic information such as age, sex, and medical history
2. Undergo a non-invasive facial scan using a smartphone-based system
3. Have a blood sample taken to measure fasting blood glucose and HbA1c
4. Complete all assessments during a single study visit

This study aims to determine whether rPPG can serve as a simple, non-invasive, and accessible tool for early detection and monitoring of diabetes in community settings.

Introduction Type 2 diabetes mellitus (T2DM) represents a major global health burden characterized by chronic hyperglycemia and associated complications. Standard monitoring methods, such as fasting blood glucose and glycated hemoglobin (HbA1c), rely on invasive blood sampling and access to laboratory facilities, which may reduce patient adherence and limit early detection. Remote photoplethysmography (rPPG), a non-contact optical technique using facial video analysis, has emerged as a promising alternative for estimating physiological and metabolic parameters. However, evidence regarding its validity in assessing glycemic markers remains limited .

Objective This study aims to evaluate the validity and diagnostic performance of rPPG-based facial scan technology in estimating blood glucose and HbA1c levels compared with standard laboratory measurements.

Methods This study employs an analytical observational design with a cross-sectional diagnostic validation approach conducted in Kelurahan Semanan, Jakarta. A total of 150-300 adult participants will be recruited using a community-based sampling method. Each participant will undergo venous blood sampling for laboratory measurement of fasting blood glucose and HbA1c, alongside a non-contact rPPG facial scan using a smartphone-based system. Agreement between methods will be assessed using Bland-Altman analysis, while correlation analysis (Pearson/Spearman) will evaluate the strength of association. Diagnostic performance, including sensitivity and specificity, will be calculated using clinical cut-offs (≥126 mg/dL for glucose and ≥6.5% for HbA1c).

Expected Results It is expected that rPPG-derived estimates will demonstrate moderate to good correlation with laboratory measurements, with acceptable agreement for screening purposes. The technology is anticipated to show reasonable diagnostic performance in identifying individuals with high glycemic risk. These findings may support the feasibility of rPPG as a non-invasive, accessible screening tool for diabetes monitoring in community settings.

Inclusion Criteria:

1. Adults aged ≥18 years
2. Willing to participate and provide informed consent
3. Able to undergo facial scan and blood examination
4. Stable clinical condition

Exclusion Criteria:

1. Facial conditions interfering with rPPG signal (e.g., wounds, deformities)
2. Use of facial coverings obstructing camera detection
3. Inability to remain still during facial scan
4. Incomplete data or withdrawal from study