UNCORRECTED PROOF Clinical Biochemistry xxx (2019) xxx-xxx Contents lists available at ScienceDirect Clinical Biochemistry journal homepage: www.elsevier.com Comparative accuracy of optical sensor-based wearable system for non-invasive measurement of blood glucose concentration Dmitry Rodin a, ⁎ , Michael Kirby a , Natallia Sedogin b , Yair Shapira a , Albert Pinhasov a , Anatoly Kreinin b a Ariel University, Ramat HaGolan St. 65, Ariel, Israel b Maale Carmel Mental Health Center Afliated to Bruce Rappaport Medical Faculty, Technion, Ela St., 17, Tirat Carmel, Israel ARTICLE INFO Keywords: Diabetes Glucose level Non-invasive glucometry Optical biosensor ABSTRACT Non-invasive biosensors for indirect evaluation of routinely-measured blood components by sweat analysis have broad potential clinical applications. This trial tested a wrist-borne non-invasive glucose monitor (NIGM) to mea- sure blood glucose (BG) levels using photoplethysmographic (PPG) optical sensors. Our aim was to determine the accuracy of the device in comparison to the standard, invasive clinical methods for blood glucose monitor- ing. Adult participants (n = 200) of both sexes from 18 to 75 were recruited for the study. Exclusion criteria: he- mophilia and other serious coagulation disorders, impaired venous access, other serious medical conditions. A biosensor was placed on the right wrist of each participant for a non-invasive indirect BG measurement. In par- allel, blood from the antecubital vein was collected and glucose levels were assessed with YSI 2300 Bioanalyzer. The measurements were performed twice: before and after food intake, with a 1-h interval between measure- ments. There were no limitations to food type and quantity. In both anteprandial (ρ = 0.8994, p < .0001) and postprandial (ρ =0.9382, p < .0001) glucose measure- ments, NIGM correlated with values obtained by the YSI 2300 reference device – there was no significant dif- ference between the two methods. Plotted on a Parkes Error Grid for Type II diabetes, NIGM readings did not deviate from those of the YSI 2300 in any clinically-significant way, with the majority of correlated readings falling within Parkes zone A. Very few readings fell within Parkes zone B. In anteprandial measurements, the mean bias between methods for all patient volunteers was 3.705 ± 7.838. In postprandial measurements gave a mean bias of 1.362 ± 10.15 for all patient glucose data. The mean absolute relative difference of currently available glucometer models ranges from 5.6% to 20.8%. The NIGM falls in the lower end of this error range at 7.40–7.54%, indicating that PPG-chemochrome sensors are capable of producing results comparable with those of direct measure glucometers. Data presented here demon- strates the reliability and accuracy of the NIGM system as an adjunctive, and perhaps substitutive, non-invasive tool for blood glucose monitoring. 1. Introduction Patients with diabetes mellitus must routinely monitor their blood glucose (BG) to better manage their condition [1], as BG levels out- side the reference range affect patient health and may lead to severe complications including weight change, neurologic symptoms, seizures, coma and even death [2]. Currently available methods for BG test- ing are invasive, cause discomfort for patients and are costly for the health care system [3]. Reliable and comfortable methods for real-time, non-invasive measurement of BG would significantly improve treatment effcacy and would also facilitate early detection of metabolic syndrome. Further, the potential for contin- uous real-time monitoring of BG would allow clinicians to add another dimension to patient health assessment not widely available at present, providing a profle of daily BG fuctuations. Biosensors for patient monitoring by sweat analysis are a promis- ing solution for non-invasive testing as components of ⁎ Corresponding author. Email address: rodin.dmitry@icloud.com (D. Rodin) https://doi.org/10.1016/j.clinbiochem.2018.12.014 Received 13 September 2018; Received in revised form 17 December 2018; Accepted 31 December 2018 Available online xxx 0009-9120/ © 2018.