A blood sugar test, also referred to as a blood glucose
test, is commonly used to measure blood glucose levels. There are four common
types of blood sugar test—fasting, random, oral, and home. Testing blood
glucose is important for patients with Type 1 diabetes, Type 2 diabetes,
gestational diabetes, and prediabetes.
If a patient suffers from diabetes, the insulin/glucose
balance does not work properly. After eating carbohydrates, blood glucose
levels rise in the blood. The pancreas releases insulin to help cells utilize
glucose for energy. If the body does not respond correctly to insulin, blood
glucose levels can rise too high, causing symptoms of high blood sugar,
including the three polyuria (increased urination), polydipsia (increased
thirst), and polyphagia (increased hunger).
Fasting Blood Sugar
Test & Results
A fasting blood sugar test is administered after a minimum
fasting time of eight hours. Patients are asked to stop eating or drinking
anything other than water the night before the test. Blood is drawn following
the fast to measure the amount of glucose in the blood.
Normal blood glucose results during a fasting blood sugar
test range from 59 to 109 mg/dL. If results fall between 110 and 125 mg/dL,
patients are said to have borderline diabetes or pre-diabetes. Results falling
at 126 mg/dL or above are a sign of diabetes. Generally, your doctor will want
to see two fasting blood glucoses above 126 mg/dL to diagnose diabetes.
A random blood sugar test follows no standard guidelines for
eating, drinking or fasting. Blood is drawn at random times throughout the day
to measure the patient's natural glucose level in their normal environment. If
a patient is healthy with no signs of diabetes, results of each random blood
glucose test should be approximately the same, as glucose levels rise and fall
minimally in healthy patients. If the measurements vary widely, it could be a
cause for additional testing.
Oral Blood Sugar Test
The oral blood sugar test, also known as the 2-hour test,
measures the amount of glucose in blood two hours after the patient consumes a
carbohydrate-rich snack or drink. This blood sugar test is most commonly used
to test for gestational diabetes in pregnant patients. Patients must fast for
eight hours before the test is completed.
Blood is drawn from patients before the glucose drink is
administered to set a baseline glucose number. Then a glucose drink or snack
containing 75 grams of glucose is consumed in the waiting room. Patients are
called back two hours after the drink is administered to have blood drawn a
second time. Normal glucose measurements should be at or below 140 mg/dL.
Measurements that fall between 140 and 199 mg/dL are considered impaired
glucose tolerance. If glucose levels are at or above 200 mg/dL, the patient may
have gestational diabetes or diabetes type II. This will be determined by your
The home blood sugar test is likely the one most diabetes
patients are familiar with. The test is administered by the patient and
requires a small amount of blood for completion. Home blood testing machines involve
a pinprick and testing of the blood by a home monitor. Diabetes patients use
home blood sugar tests to monitor the rise and fall of glucose levels in
association with food intake. Based on the results, patients may alter diet,
use physician-prescribed insulin or take oral diabetes medications to help
maintain healthy blood glucose levels.