The serum glucose blood test measures the amount of glucose in the blood sample obtained from the patient. The test is usually performed to check for elevated blood glucose levels which can be an indication of diabetes or insulin inhibition.
The carbohydrates that make a larger portion of the food are broken down into glucose. For most of the cells in the body, glucose makes for the major source of energy. The glucose in the blood is controlled by a hormone called insulin. However, if a person consumes too much carbohydrates or simple sugars, the amount of glucose in the blood can rise beyond the amount that insulin can control. In another case, there may be some problems with the production of insulin because of which glucose in the blood stream cannot be controlled.
There are two types of serum glucose testing. One is the fasting serum glucose test in which the patient should not have eaten for at least 6-8 hours before the test, and the other test can be performed randomly at any given time. Unlike the fasting test, which establishes the glucose level in the blood without eating anything, the random test can be done at any time of the day. However, the results of the random test depend on what you consume before the test and the kind of physical activity that you have been doing.
Doctors usually prescribe this test if there have been symptoms of diabetes. For patient who have been diagnosed with diabetes and are continuing treatment, serum glucose test could also be used to monitor the efficacy of the treatment.
Though the normal results vary, the amount of glucose up to 100 milligrams per deciliter (mg/dL) is usually considered to be a normal result. In persons who have a glucose level higher than 100 mg/dL but lower than 126 mg/dL, this may be an indication of prediabetes or abnormal fasting glucose in case the test was taken after fasting.
For those, whose blood glucose is higher than 126 mg/dL, the test results show diabetes. The levels of glucose, when above normal may indicate disorders like Cushing syndrome, hyperthyroidism, diabetes mellitus, acromegaly, pancreatic cancer, pheochromocytoma and pancreatitis.
Hypoglycemia, or blood sugar levels which are lower than normal indicate disorders like hypothyroidism, hypopituitarism and insulinoma.
Though usually the serum glucose tests are accurate, severe stress or conditions like a recent stroke or trauma are likely to increase glucose levels in the blood temporarily.