Blood glucose, also known as blood sugar, provides all of the energy human cells need and use. When the systems regulating blood glucose levels don't work correctly, disease can occur and health may suffer. Blood glucose is easily monitored with home monitors or through blood tests taken at a doctor's office.
Chemistry
Glucose is a monosaccharide--a type of complex carbohydrate that's formed of a chain of carbon atoms with hydrogen and alcohol groups bound to its central chain--as explained in the Elmhurst College Virtual Chembook. In the human body, all food is broken down into glucose, which then circulates in the bloodstream and provides a source of energy for all bodily activity. When blood glucose is high and energy needs are low, glucose is converted into glycogen for short-term use or into fat to be stored for later use. When blood glucose is low and energy needs are high, the body can convert fat into glucose for immediate use.
Biological Interactions
Blood glucose interacts with other substances as the body attempts to maintain a healthy level of sugars in the system. Insulin and glucagon, two enzymes made by the islet cells of the pancreas, are key compounds in the control of blood glucose. Insulin helps maintain blood glucose levels by turning on the conversion of blood glucose into fat whenever blood sugar becomes too high. When blood sugar is too low, glycogen works to convert fat into blood glucose and raise the levels in the blood.
Healthy Levels
In healthy people, blood glucose levels below 100 milligrams per deciliter (mg/dL) are considered normal, according to Medline Plus. Levels between 100mg/dL and 126mg/dL are labeled as prediabetes, a condition that may lead to diabetes if blood sugar remains uncontrolled. When blood sugar levels rise above 126mg/dL, this generally results in a diagnosis of diabetes--a condition of chronic high blood sugar that can lead to complications throughout the body. All of these levels reflect a fasting blood glucose reading, a reading in someone who has not eaten for several hours. After a meal, blood glucose may rise up to 180mg/dL and still be within a normal range.
Diseases
Diabetes is a condition in which insulin is either not produced at all or the body is unable to properly use insulin to control blood sugar. Hypoglycemia occurs when blood glucose becomes too low, generally considered under 70mg/dL. Hyperglycemia is high blood glucose, typically over180mg/dL. Hypoglycemia and hyperglycemia can occur as a result of diabetes, the New York State Department of Health says.
Testing
A blood glucose test can be performed to monitor levels of sugar in the blood. Blood glucose tests are typically given to anyone suspected of having diabetes and to pregnant women to monitor for gestational diabetes, a condition of temporary diabetes that sometimes occurs during pregnancy. Blood glucose tests can also be given to diabetics to determine whether the treatment regimen they follow is working. These tests are done on a blood sample taken from the arm, usually taken after at least six hours of fasting. Home monitoring can be done by diabetics using a device that pricks the finger to draw blood and a small device that can measure glucose levels in a small sample of blood smeared onto a special test paper.
