Díaz Lab Testing Store › Fasting Glucose | Serum (Quest) Image 1 of 1 Fasting Glucose | Serum (Quest) $27.00 The primary blood sugar marker — elevated fasting glucose is the first sign of insulin resistance and pre-diabetes. Add To Cart Added! The primary blood sugar marker — elevated fasting glucose is the first sign of insulin resistance and pre-diabetes. Add-on | Interpretation for Individual Markers $17.00 Add Added!