Diabetes is a serious ailment, which can arise for many reasons, and can affect many systems in the human body. Diabetes, often called “sugar” by patients, is diagnosed and monitored mainly through a simple blood test – the Blood Glucose level.
Glucose is a type of sugar found in fruits and many other foods (this includes lactose and fructose). It is the main source of energy used by the body. Most of the carbohydrates that people eat are also turned into glucose, which can be used for energy or stored in the liver and kidneys as glycogen.
To stop the sugar levels just increasing daily, a balance is achieved through a hormone called Insulin which helps the body use and control the amount of glucose in the blood. Insulin is produced in areas of the pancreas called ‘islets’ and released into the blood when the level of glucose in the blood rises. In simple terms, people who do not produce enough insulin develop diabetes. People can also develop diabetes if they do not respond normally to the insulin their bodies produce. This occurs most commonly when a person is overweight, and since obesity is on the rise, so are various types of diabetes.
Normally, blood glucose levels increase slightly after a person eats a meal. This increase causes the pancreas to release insulin so that blood glucose levels do not get too high. Blood glucose levels that remain high over time can cause damage to the eyes, kidneys, nerves, and blood vessels, which explains why good glucose control is important.
There are many ways to carry out blood glucose tests, including fasting blood sugar (FBS). This is a measurement of blood glucose after fasting for 12 to 14 hours. For an accurate fasting blood sugar test, do not eat or drink for 12 to 14 hours before the blood sample is taken. However, water can be freely taken, as otherwise hemoconcentration occurs to give a falsely high reading. This is often the first test done to detect diabetes, and explains why fasting blood tests are usually done when having a medical check-up.
The other common test is called the random blood sugar (RBS). A random blood sugar measurement may also be called a casual blood glucose test. This is a measurement of blood glucose that is taken regardless of when the person last ate a meal. Sometimes several random measurements are taken throughout a day. Random testing is useful because glucose levels in healthy people do not vary widely throughout the day, so wild swings may indicate a metabolic problem.
Glucose tolerance testing can also be done, usually to confirm a condition known as gestational diabetes, which can occur during pregnancy. An oral glucose tolerance test is simply a series of blood glucose measurements taken after a person drinks a liquid containing a specific amount of glucose; however, this test is not used to diagnose diabetes.
To monitor the treatment of diabetes, there are another couple of tests which can be carried out. The commonest is Glycated Hemoglobin, otherwise referred to as HbA1c. This test actually is an indicator of the average glucose concentration over the life of the red blood cells (which is taken as over the previous three months).
Another is the Serum C-Peptide which is used to investigate low blood sugar levels, done by measuring the C-Peptide which is produced by the Beta cells in the pancreas.
“Normal” levels may vary from lab to lab, but generally the range taken for FBS is that the level should be less than 110 milligrams per deciliter (mg/dL).
Diagnosis of diabetes needs a fasting blood glucose level higher than 125 mg/dL on two separate days.
A fasting glucose level below 40 mg/dL in women or below 50 mg/dL in men that is accompanied by symptoms of hypoglycemia (low blood sugar) may indicate an insulinoma, a tumor that produces abnormally high amounts of insulin. Lower than expected glucose levels can also indicate Addison’s disease, an underactive thyroid gland or pituitary gland, liver disease (such as cirrhosis), malnutrition, or a problem that prevents the intestines from absorbing the nutrients in food.
So you can see “sugar” is important which is why we have specialist endocrinologists at my hospital.