Diabetes mellitus, or diabetes as it is more commonly called, occurs when sugar in the blood accumulates in the body, rather than being expended as energy. Individuals feel sick and sluggish.
When diabetes is undiagnosed and untreated, it can result in severe damage to the major organs, or cause health problems like heart or kidney disease. Blood sugar levels are used to diagnosis, monitor, and aid in treating diabetics.
Type 1 diabetes, occurs when is a shortage or lack of insulin in the body. This type may also be called childhood or juvenile diabetes. Type 2, or adult-onset diabetes, is the most common type of diabetes, and experts fear it is reaching epidemic proportions. In this article, the focus is on diabetic sugar levels that relate to type 2 diabetes.
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How are Sugar Levels Tested?
Blood sugar, or glucose, levels are measured by glucose tolerance tests. The most commonly used tests to determine normal, pre-diabetes, and diabetes blood sugar levels are: fasting blood sugar (FBS,) 2 hour postprandial, oral glucose tolerance tests, and random or casual blood sugar (RBS.)
A FBS is often the first test done when a doctor suspects a person has diabetes. The individual fasts for eight hours prior to the test, and the doctor is looking for blood glucose results in the 70 to 99 mg per deciliter range. This is typical written thus: 70 – 99 mg/dL. A FBS of 126 mg/dL, plus any symptoms of diabetes such as excessive thirst, hunger, or urination, would be a red flag. At the other end of the spectrum, a blood sugar level in the range of 40 mg/dL or lower for females, or 50 mg/dL for males, is excessively low and individuals should discuss this condition with their doctor.
2 Hour Postprandial
This is a precise test, performed exactly two hours after the individual has eaten a meal. These tests are easily done at home by using a blood glucose meter, and offer a convenient way for patients to self-monitor their diabetes. The individual takes a tiny blood sample, usually from a finger, and applies it to a testing strip, and then reads the results. The blood sugar levels reveal how well the patient is responding to a diabetes diet, insulin, or diabetes medications that may be a part of their treatment protocol.
Two-hour postprandial results should be in the 70 to 145 mg/dL range. Test results of 200 mg/dL or higher twice in a row should be reported to your doctor.
Random or Casual
Random blood sugar tests are typically performed at the doctor’s office, as blood must be drawn from the vein. They can be done at anytime regardless of when the person last ate, hence the name random. The normal range for an RBS is 70 to 125 mg/dL, and results of 200 mg/dL or higher, plus any other symptoms of diabetes, should be discussed with a healthcare professional.
Random testing of blood glucose levels can be a first symptom signal when they reveal patterns of fluctuating blood sugar levels in individuals that have not been diagnosed with diabetes. For those with diabetes, this type of testing can help monitor the effectiveness of diet, insulin, or medications.
Oral Glucose Tolerance Levels
Oral glucose tolerance tests can be used to diagnose pre-diabetes and diabetes, but are most commonly used to test for gestational diabetes (diabetes resulting from pregnancy.) Individuals drink a glucose-laden drink, and then blood is drawn several times, and measured for glucose levels.
How do My Blood Sugar Levels Affect My Health?
What does all this mean in simple terms? Normally, blood glucose levels peak at 200 mg/dL and drop to 120 mg/dL, or less, in two hours. However, when a person has diabetes, blood glucose levels peak about 200 mg/dL and do not drop to 120 mg/dL or lower after two hours.
Doctors rely on more than just one test to diagnose diabetes. According to a report from the University of Michigan Health System, “The American Diabetes Association (ADA) criteria for diagnosing diabetes are met when any of the following results are repeated on at least two different days.”
- FBS of 126 mg/dL or higher
- 2 hour oral glucose tolerance of 200 mg/dL or higher
- RBS of 200 mg/dL
- Symptoms such as excessive thirst, hunger, or urination, dizziness, excessive weight gain or weight loss
It is extermely important for diabetics to monitor sugar levels closely. If you have a family history of diabetes, you may want to consult with your healthcare professional about pre-diabetes testing. Because of the severe health problems associated with diabetes, individuals should take every precaution to avoid contracting this disease.
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University of Michigan Health System, “Blood Glucose,” Caroline Rea, RN, BS, MS, 7/2007, accessed 08/11/2010
Carillion Medical Center, Diabetes Management Survival Skills Tool Kit, 2009