This is a single-center, open-label, prospective study. Blood glucose is measured at different time points during oral glucose tolerance test and hypoglucose clamp test in healthy subjects, using both venous plasma and multi-channel microspatial offset Raman scattering spectroscopy (mμSORS). Venous plasma glucose was set as gold standard. The two measurements were collected synchronously so as to calculate the mean absolute relative difference (MARD) and the consensus error grid (CEG). Accuracy of non-invasive blood glucose testing by mμSORS will be in-depth validated specifically in the 3-10 mmol/l glucose range.

In order to clinically verify the accuracy and safety of non-invasive blood glucose measurement by the mμSORS technology specifically in the 3-10 mmol/l glucose range, this study will conduct oral glucose tolerance tests and hypoglucose clamp tests on healthy subjects at different time points during the tests. In oral glucose tolerance tests, there will be 9 points as follows: 0-min and post glucose-load 30-min, 60-min, 90-min, 120-min, 150-min, 180-min, 210-min and 240-min. While in hypoglucose clamp tests, blood glucose will be set at around 3.0-4.0mmol/l for about 1.5-2.0 hours, blood glucose will be detected every 10 minutes.

Inclusion Criteria :

• Male or female.
• Aged>=18 years for OGTT participants or aged between 20 and 40 years for hypoglucose clamp tests participants.
• Fasting blood glucose (FPG) < 6.1 mmol/L and glycated hemoglobin (HbA1c) < 5.7% during the screening period.
• There are no scars, obvious pigmentation and other factors that interfere with the detection of the palm skin to be tested.
• Confirmed as healthy based on the results of physical examination, medical history, vital signs and clinical laboratory tests.
• Fully understand the nature, significance, possible benefits, possible inconveniences or potential risks of this research, and should also understand the research procedures, be willing to complete the entire research process, and provide written consent form.

Exclusion Criteria :

• With diabetes history.
• Any history of serious clinical diseases such as circulatory system, endocrine system, nervous system, digestive system, respiratory system, hematology, immunology, psychiatry or metabolic abnormality, or any other disease that can interfere with the test results, which the investigator considers significant.
• Alcohol dependency or drug abuse.
• Those who have participated in clinical trials of other drugs within 3 months before screening (since the last visit of the previous trial).
• Those who have used any drugs that affect blood glucose levels (such as insulin, oral hypoglycemic drugs, steroid hormones, thyroxine, etc.) within 28 days before screening;
• Pregnancy or lactation period.
• Difficulty in venous blood collection or fainting of needles or blood.
• Other circumstances that the investigator considers inappropriate to participate in the study.