Blood sugar is the amount of glucose present in the blood. It provides the body with energy, but too little or too much can cause health problems. Blood sugar can be measured a few different ways. A fasting blood glucose test is performed after eight hours of not eating. A random blood glucose test can be done anytime to check sugar levels.

Both tests may be done to help diagnose a medical condition. For example, most pregnant women are screened for gestational diabetes. Random blood sugar checks are also done by people who need to keep a close eye on their sugar level.

Normal results for a fasting blood sugar test are 70 to 100 mg/dl (milligrams per deciliter). In a test done without fasting, normal blood sugar levels are between 70 and 140 mg/dl. If levels are below 70 mg/dl, the condition may be referred to as hypoglycemia, meaning low blood sugar. When the levels are higher than 140 with a non-fasting test, the condition may be called hyperglycemia.

Blood sugar can be tested from a small amount of blood drawn. Although tests can be performed at a hospital or lab, small home glucose monitoring devices are available. A small amount of blood is obtained, usually through a finger stick, and placed in a meter which calculates glucose levels and provides a digital readout in only a few seconds.

Certain medical conditions cause high blood sugar levels, the most common of which is diabetes. Normally the body produces insulin to convert food into energy. In people with diabetes, insulin is not produced adequately. Other medical conditions which may cause high blood sugar levels include hyperthyroidism and pancreatitis.

A common cause of low blood sugar is not eating enough. Individuals with eating disorders, such as anorexia, may have low blood sugar. Additional medical problems which may cause blood sugar levels to drop include hypothyroidism and liver disease.

A number of different symptoms can occur with abnormal blood sugar levels. When blood sugar levels are too high, symptoms such as confusion may appear. If levels drop too low, an individual may become shaky, have a rapid heart rate, and have some mental confusion.

Depending on the cause of abnormal blood sugar levels, treatment may be needed. Some people with diabetes and high blood sugar may need to make adjustments to their diet or add certain medications to control levels. If diet does not maintain normal blood sugar levels, insulin may be needed.

Blood sugar which is too low may also need to be treated or dietary adjustments made. Eating several small, healthy meals throughout the day may help to maintain steady blood sugar. Since alcohol could lower sugar levels, limiting the number of alcoholic beverages may also help.