Systems and methods for determining an abnormal glycemic event using surrogates for glucose are disclosed herein. In an embodiment, a medical system includes a medical device associated with a subject and a processor communicatively coupled to the medical device. The medical device is configured to sense a signal corresponding to a presence of a compound in at least one of: an exhalation breath, interstitial fluid, blood and urine, wherein the compound is a surrogate for glucose. The processor is configured to receive the signal corresponding to the presence of the compound； determine the presence of the compound based on the received signal； and determine the subject is experiencing an abnormal glycemic event in response to the determined presence of the compound.
