Glucose in the blood.
The amount of glucose in a person's blood.
Presence of glucose in the blood (which is always true), and (usually, more specifically) average concentration thereof over time, and its regulation; in this sense, glycemia is hypernymic to euglycemia, hyperglycemia, and hypoglycemia, and a mention of glycemia is a reference to blood sugar regulation and degree or quality thereof.
(occasionally, ambiguously) Hyperglycemia.