Glucose binds to hemoglobin in red blood cells at a steady rate. Since red blood cells last 3 to 4 months, the A1c test shows how much glucose is in the plasma part of blood. This test shows how well your diabetes has been controlled in the last 2 to 3 months and whether your diabetes treatment plan needs to be changed.
http://www.webmd.com/diabetes/glycohemoglobin-ghb
A glucose test measures the amount of glucose in your blood. Glucose, also known as sugar, is your body’s main source of energy. Your body converts the carbohydrates you eat into glucose. Glucose testing is done primarily to check for type 1 diabetes, type 2 diabetes, and gestational diabetes. Diabetes is a condition that causes your blood glucose to rise. In healthy individuals, the glucose level is managed in the body by a hormone called insulin. However, if you have diabetes, your body does not make enough insulin or the insulin does not work properly. This causes your blood glucose to rise. If left untreated, high levels of blood glucose can cause organ damage.
http://www.healthline.com/health/glucose-test-blood
The results should be available in a few days. If the reading is too high, which happens 15 to 23 percent of the time, you'll be asked to come back for a three-hour glucose tolerance test to see whether you really do have gestational diabetes.
http://www.babycenter.com/0_glucose-screening-and-glucose-tolerance-tests_1483.bc
Guide. A glycohemoglobin test, or hemoglobin A1c, is a blood test that checks the amount of sugar (glucose) bound to the hemoglobin in the red blood cells. When hemoglobin and glucose bond, a coat of sugar forms on the hemoglobin. That coat gets thicker when there's more sugar in the blood.
http://www.webmd.com/diabetes/glycohemoglobin-ghb
Blood glucose: when you are older than 45 years or have risk factors for diabetes; when you have symptoms suggesting high or low blood glucose; during pregnancy; when you are diabetic, self-checks up to several times a day to monitor blood glucose levels. Urine glucose: usually as part of a urinalysis.
https://labtestsonline.org/understanding/analytes/glucose/tab/glance
A blood sample drawn from a vein in your arm or a drop of blood from a skin prick; sometimes a random urine sample is used. Some diabetics may use a continuous glucose monitor, which uses a small sensor wire inserted beneath the skin of the abdomen to measure blood glucose at frequent intervals and provides a result.
https://labtestsonline.org/understanding/analytes/glucose/tab/glance
To determine if your blood glucose level is within a healthy range; to screen for and diagnose diabetes and prediabetes and to monitor for high blood glucose (hyperglycemia) or low blood glucose (hypoglycemia); to check for glucose in your urine.
https://labtestsonline.org/understanding/analytes/glucose/tab/glance
In general, it is recommended that you fast (nothing to eat or drink except water) for at least 8 hours before having a blood glucose test. For people with diabetes, glucose levels are often checked both while fasting and after meals to provide the best control of diabetes.
https://labtestsonline.org/understanding/analytes/glucose/tab/glance
Using Test Results as a Tool for Change. Your blood glucose levels do not reflect your value as a person. They are just a measure of disease activity. Stressing over your glucose readings is counterproductive. It will only hurt your ability to successfully manage your diabetes. Diabetes is a very serious condition.
http://www.healthline.com/health/type-2-diabetes/random-glucose-testing
A random glucose test is exactly what it sounds like. It’s a random blood test to check glucose levels. It’s a powerful tool for diabetics. Also called casual testing, it can help assess how well the disease is being managed. Health professionals recommend that you use the post-meal glucose level as the standard for random glucose testing. Acceptable values are around 70-125 mg/dL (3.9-6.9 mmol/L).
http://www.healthline.com/health/type-2-diabetes/random-glucose-testing
what is glucose in blood test
70 to 125 milligram per deciliter glucose is in blood test.  A glucose in blood test is 70 to 125 milligrams per deciliter.