The study is an open-label, prospective, within-subject comparison of the Bios device readings versus venous blood sample glucose readings, glucose readings from a Dexcom CGM and an SMBG device in subjects previously diagnosed with Type 1 or Type 2 diabetes mellitus.

Inclusion Criteria:

1. Subject is at least 18 years of age;
2. Subject has had a diagnosis of diabetes mellitus either Type I or Type II;
3. For insulin-using subjects only: subject will not inject insulin or wear an insulin pump insertion set within a 10 cm distance of any Bios device;
4. Subject able to wear multiple CGM devices simultaneously;
5. Subject is either a patient diagnosed with Type I diabetes mellitus currently wearing a Dexcom CGM device or a patient diagnosed with Type II diabetes mellitus who will agree to use a Dexcom CGM device during participation in the study. There are no restrictions on the model of the Dexcom CGM device.
6. Subject agrees to provide a log of medications (prescription and over-the-counter) and dietary supplements (e.g., vitamins) taken during the study period, including dosage;
7. Subject has a smart device that complies with the requirements listed in Attachment 1 of this protocol and is willing to download and run the GraphWear Patient application on their device;
8. Subject is able to read and understand the Informed Consent Form and has voluntarily provided written informed consent;
9. In the Principal Investigator's opinion, subject is able to be compliant with provisions laid out in this protocol.

Exclusion Criteria:

1. Subjects with any physical or behavioral disorder, which, in the opinion of the Principal Investigator, may interfere with the use of the device or compliance with the study protocol;

2. Subject has any of the following:

   • a skin condition that precludes wearing of the device;
   • a known allergy that precludes wearing of the device;
   • tattoos or other skin alterations that may interfere with device placement and/or operation;

3. History of substance abuse within 6 months of study start;

4. Use of any illicit drugs during the duration of the study period;

5. Marijuana use during the duration of the study period;

6. If female, subject is pregnant or nursing;

7. Subject is on active dialysis;

8. Subjects whom the Principal Investigator believes may not be an appropriate candidate for this device.

Subjects previously diagnosed with Type 1 or Type 2 diabetes mellitus