Blood glucose tests typically are used to measure the amount of glucose in the blood. Sometimes performed at health fairs and included in routine physical exams, blood glucose testing can help to screen for diabetes and pre-diabetes. Screening usually is recommended for people believed to be at high-risk of developing diabetes. Glucose results typically are interpreted based on the type of test given and the timing of the test. The amount of glucose present in your blood can indicate certain adverse health conditions.
Glucose testing can be used to diagnose diabetes in people with symptoms of hyperglycemia, like increased thirst, fatigue, blurred vision, increased urination, and slow-healing infections. High levels of glucose typically indicate diabetes, but there are a number of other conditions that can cause elevated glucose results. Cushing syndrome, hyperthyroidism, pancreatic cancer, pancreatitis, chronic renal failure, and certain drugs can cause elevated glucose. People with hypoglycemia symptoms – like sweating, hunger, anxiety, confusion, hunger, and blurred vision – also may undergo glucose testing. Low levels of glucose typically indicate hyperglycemia, which can be caused by adrenal sufficiency, certain drugs, liver disease, hypopituitarism, hypothyroidism, starvation, alcohol use, and insulin overdose.
There are different types of glucose tests. In a fasting glucose test, blood is drawn and glucose is measured after an eight- to ten-hour fast. People undergoing fasting glucose testing typically should have nothing to eat or drink except water during the fast before the test. For an oral tolerance test, blood is drawn from a person after drinking a measured glucose solution.
Diabetics may test their blood glucose levels several times each day. When a blood glucose test is ordered, a blood sample usually is drawn from the arm and analyzed. Diabetics who self-check usually take a drop of blood from a skin prick and test it in a portable meter. Typically, diabetics are educated on how to interpret their glucose results daily.
Glucose results are interpreted differently depending on the type of test administered. With fasting glucose screening, levels from 70 to 99 indicate normal fasting glucose while levels from 100 to 125 indicate pre-diabetes. Levels of 126 or above may indicate diabetes. With glucose results from an oral tolerance test, levels below 140 indicate normal glucose while levels of 140 to 200 indicate pre-diabetes, and levels over 200 may indicate diabetes. When glucose results are at levels that indicate diabetes, the test usually will be repeated to confirm a diagnosis.
