What is Fasting Glucose?

Through the night the liver releases stored glucose and the tissues take it up. The fasting figure is what those two leave in the blood by morning. It is a direct reading of the sugar itself, not an average over time or a figure worked out from others, and it is one of the tests used to diagnose diabetes.

Fasting Glucose gives the sugar; Fasting Insulin gives the hormone holding it there. HOMA-IR is the two multiplied together, a single figure for how much insulin it is taking to hold that much sugar.

What was eaten the day before and how long the overnight fast has run both move the figure from one morning to the next. The slower influence is how sensitive the tissues are to insulin, which shifts over weeks as weight and activity change.

HbA1c, measured three times a year, already follows the accumulated average. The yearly Fasting Glucose adds what an average cannot carry, a direct reading of the sugar at a single point in that year. This is Do Health's monitoring schedule, not a general recommendation for everyone.