Subjects with type 1 diabetes will be observed in the diabetes research center clinic following a meal and an insulin injection. Breath and sweat samples will be collected at intervals throughout the visit, with increased frequency during hypoglycemia. Collaborators with the MITRE Corporation will perform analyses on these samples to identify any relationships between volatile organic compounds in breath and sweat and hypoglycemia.

Subjects enrolled in the study will have clinical type 1 diabetes managed with rapid acting insulin. After consent and enrollment, they will arrive to the study visit having fasted the night before. Subjects will be given a meal, and will be given an insulin injection for this meal, calculated based on their prescribed meal to carbohydrate ratio as well as a correction bolus to correct their current plasma glucose value down to 40 mg/dL based on their prescribed insulin sensitivity factor. Following the insulin injection, subjects will eat breakfast and be observed in the clinic setting. Blood, breath, and sweat samples will be collected throughout the study visit with increased frequency of collection during hypoglycemia. Collaborators with the MITRE Corporation will perform analyses on these samples to identify any relationships between volatile organic compounds in breath and sweat and hypoglycemia. After subjects reach the hypoglycemia threshold, they will be allowed to eat and drink and their blood sugar will be monitored for stability prior to discharge.

Inclusion Criteria:

• Informed consent by the subject documented prior to any study procedures
• Age ≥ 18 years
• Have had clinical type 1 diabetes for at least one year
• Willing and able to avoid deodorant, scented lotions, and scented laundry detergent on your clothes on the day of the visit

Exclusion Criteria:

• Unable to provide informed consent (e.g. impaired cognition or judgment)

• Unable to safely comply with study procedures and reporting requirements (e.g. impaired memory or unable to speak and read English)

• Current participation in another diabetes-related clinical trial that, in the judgment of the principal investigator, will compromise the results of this study or the safety of the subject

• Pregnancy (positive urine HCG), breast feeding, plan to become pregnant in the immediate future, or sexually active without use of contraception

  • Subjects must use acceptable contraception for the two weeks prior to the study, throughout the study and for the two weeks following the study.
  • Acceptable contraception methods include:
  • Oral contraceptive pill (OCP)
  • Intrauterine Device (IUD, hormonal or copper)
  • Male condoms
  • Female condoms
  • Diaphragm or cervical cap with spermicide
  • Contraceptive patch (such as OrthoEvra)
  • Contraceptive implant (such as Implanon, Nexplanon)
  • Vaginal ring (such as NuvaRing)
  • Progestin shot (such as Depo-Provera)
  • Male partner with a vasectomy proven to be effective by semen analysis

• Abnormal EKG consistent with coronary artery disease or increased risk of malignant arrhythmia including, but not limited to, evidence of active ischemia, prior myocardial infarction, proximal LAD critical stenosis (Wellen's sign), prolonged QT interval (> 440 ms). Non-specific ST segment and T wave changes are not grounds for exclusion in the absence of symptoms or history of heart disease. A reassuring evaluation by a cardiologist after an abnormal EKG finding may allow participation.

• History of hypoglycemic seizures (grand mal) or coma in the last year

• History of poor venous access or inadequate venous access as determined by trial nurse or physician at time of screening

• Hemoglobin < 12 g/dl for men, < 11 g/dl for women

• Any factors that, in the opinion of the principal investigator would interfere with the safe completion of the study

Volunteers who fit the selection criteria will be considered as candidates for this study. The study team will contact individuals who have previously inquired about participation in our studies and have asked to have their contact information kept on file. In addition, advertisements for the study may be posted at the MGH Diabetes Center and other places, and may be distributed in the weekly broadcast email of research studies seeking volunteers. A letter may be sent to adult endocrinologists in the Boston metropolitan as well as selected nearby endocrinologists informing them of the study and asking them to refer any eligible patients who might be interested.

The study data may be shared with collaborators at the MITRE Corporation (a non-profit research corporation), but only in a form in which all personally identifiable information has been removed. Shared data will be in the form of a database in which only a number identifies subjects.