What it is: A glucose blood test measures the level of glucose (sugar), the body's main energy source, in the blood.
Why it's ordered: Ordered to screen for or diagnose diabetes and prediabetes, monitor existing diabetes, or evaluate symptoms like excessive thirst, frequent urination, or unexplained fatigue.
What it detects: Glucose levels reflect how well the body is regulating blood sugar via insulin. Persistently high levels point toward diabetes; low levels (hypoglycemia) can reflect medication effects, certain illnesses, or, less commonly, other metabolic conditions.
Collection & prep: Can be done via finger-prick or a standard blood draw from a vein. A fasting glucose test requires 8–12 hours without food or drink (except water) beforehand; random or post-meal glucose tests don't require fasting.
Results:
Fasting: 70–99 mg/dL – normal
Fasting: 100–125 mg/dL – prediabetes
Fasting: 126 mg/dL or higher (on more than one occasion) – diabetes
Possible complications of abnormal glucose: A single abnormal result doesn't confirm diabetes — diagnosis typically requires repeat testing or an additional test like HbA1c; untreated high blood sugar over time raises the risk of nerve, kidney, eye, and cardiovascular damage.
What it is: A glucose blood test measures the level of glucose (sugar), the body's main energy source, in the blood.
Why it's ordered: Ordered to screen for or diagnose diabetes and prediabetes, monitor existing diabetes, or evaluate symptoms like excessive thirst, frequent urination, or unexplained fatigue.
What it detects: Glucose levels reflect how well the body is regulating blood sugar via insulin. Persistently high levels point toward diabetes; low levels (hypoglycemia) can reflect medication effects, certain illnesses, or, less commonly, other metabolic conditions.
Collection & prep: Can be done via finger-prick or a standard blood draw from a vein. A fasting glucose test requires 8–12 hours without food or drink (except water) beforehand; random or post-meal glucose tests don't require fasting.
Results:
Fasting: 70–99 mg/dL – normal
Fasting: 100–125 mg/dL – prediabetes
Fasting: 126 mg/dL or higher (on more than one occasion) – diabetes
Possible complications of abnormal glucose: A single abnormal result doesn't confirm diabetes — diagnosis typically requires repeat testing or an additional test like HbA1c; untreated high blood sugar over time raises the risk of nerve, kidney, eye, and cardiovascular damage.
Statements made in the Clinical Manual have not been evaluated by the FDA. The products mentioned are not intended to diagnose, treat, cure or prevent any disease.
