Brought to you jointly by The Foundation for Prevention and Dr. Irving A. Cohen
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How can your doctor test you for prediabetes?
There are many diagnostic tests that your doctor can use to evaluate you for prediabetes or type 2 diabetes. Your physical examination, your medical history, your family history, and listening to any complaints and symptoms that you discuss may all give your doctor clues. If you have to pick the single most meaningful, it is the A1c. This test provides a window into your blood sugar level averaged over the past several months. Here are some ways your doctor may evaluate you:
- A1c. This test is known as hemoglobin A1c or glycosolated hemoglobin. It measures the percentage of your red blood cells that have been modified by your sugar level. Since your blood cells last several months, this provides a picture of your average blood sugar over a period of the past two to three months. In the past, 6% was considered it a the cutoff figure to differentiate between normal and diabetes. However, newer recommendations are more confusing! There is a very slight increase in risk above 5.7% so these are sometimes considered abnormal. However, those risks go up considerably and at a much faster rate once 6% is past. Recently, the government designated people who are between 5.7% and 6.5% as prediabetic. Despite the increased risk of disease from high blood sugar, there are now also recommendations that diabetics should not go below 7%. That caution pertains to those diabetics receiving medication, since diabetic medication when used too aggressively causes severe hypoglycemia, which increases the rate of death by stroke! When using dietary control without medication, A1c should be brought down all the way to normal ranges.
Sometimes this test may falsely give a low reading. People with a genetic blood disorder, and people who have recently experienced a large blood loss, such as from surgery, may get an inaccurate reading. In that case, a Fructosamine test may be substituted.
Insurance companies may restrict the A1c in people who have not yet been deemed diabetic, despite it being the best available test. If is the case, pay for it out of pocket if you can. It is well worth it.
- C-reactive protein. This test does not measure your sugar, but instead it is a marker for inflammation. This inflammation can be present in the metabolic syndrome and is associated with the harm done by excessive insulin levels and insulin resistance. It is the next most important test for prediabetes.
- Fasting insulin level. Many people mistakenly believe that diabetes means that you lack a sufficient level of insulin. While that is totally true for Type 1 diabetics, they only represent about 5% of the diabetics in the U.S. Today, most diabetics are Type 2 diabetics, which is more complex. Type 2 Diabetes is characterized by insulin resistance. Your body reacts to a high level of sugar in your blood by telling your pancreas to produce more insulin. The cells that receive the insulin signal may gradually become more resistant to this insulin excess. As this insulin resistance increases you have to produce even greater amounts of insulin to cope. It is only in the very late stages of type 2 diabetes that your pancreas can not produce sufficient insulin. A high insulin level can be a marker for insulin resistance in the early stages of prediabetes and type 2 diabetes. This may be a very useful test for young women suffering from Polycystic Ovary Syndrome, which is another manifestation of insulin resistance.
- Glucose tolerance test. This test comes in a variety of lengths, typically two to five hours. It requires you to stay in the laboratory, while they give you a measured amount of sugar to drink and repeatedly draw blood at specific intervals. Needless to say, neither the patient nor the laboratory love it. It does provide valuable information, demonstrating how your body reacts to high sugar levels, whether it brings them down to normal, and it can demonstrate abnormal reactions found in people with reactive hypoglycemia, another precursor to Type 2 Diabetes.
- Fasting glucose. This is the most common tests given, usually as part of an annual chemistry panel. It only shows what your blood sugar is after you have been fasting overnight. In the early stages of type 2 diabetes, or a prediabetes, your body is still capable of bringing high sugar levels down in that extended time period. Therefore, it can completely miss the diagnosis while your body is being actively harmed. Although is useful to know and does provide a diagnosis when it is high, a normal reading does not mean you do not have Prediabetes.
- Fructosamine. As described above, this test is an alternative when the A1c may not be accurate. It also represents your average blood sugar, but over a shorter period of two to three weeks.
- Home glucose monitoring. You would not expect someone who has not been diagnosed with diabetes to use home monitoring, but it is sometimes done when another family member is diabetic. People may borrow their relative's glucose meter to check their own blood sugar. If you do this, don't waste at this valuable information. Share it with your physician. The three best times to record this are first thing in morning before eating, two hours after eating, and if you are experiencing a hypoglycemic episode, such as feeling lightheaded, dizzy, or anxious.
- Your waist measurement. In American men and women, a waist circumference greater than 40 inches for men and 35 inches for women usually signals the metabolic syndrome. This is because some the conditions that bring type 2 diabetes about also bring about abdominal obesity. This obesity is not just subcutaneous fat deposited under your skin, but also includes omental fat draped over your abdominal organs. These numbers are even lower if you have Asian or Latin American ancestry. The ratio between your waist circumference and your hip circumference can also provide valuable information.
- Your weight. Although it is not a guarantee, overweight increases the risk of developing diabetes. However, you need to know that some diabetics are considered with in the normal weight range. Also, your ethnic heritage and muscular development may influence what is considered it your normal healthy weight range. Although BMI or body mass index is often used in government studies, it is a poor measurement for individual decisions. When time and equipment allow, estimating your percentage of body fat can lead to better decisions regarding healthy weight goals.
- Your physical examination. Your doctor may notice physical problems associated with diabetes. One example is diminished feeling or loss of sensation to vibration in your feet and legs, which could be due to early stages of a peripheral neuropathy.
- Your family history. Diabetes in close relatives in your family of origin can point to both genetic and cultural factors that increase your risk.
- What you have to say. Tell your doctor about problems you are experiencing. It may help with your diagnosis. The single most important skill in any doctor should have is to listen to his or her patient when making a diagnosis.
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** Diabetes is a serious disease. This website can not and is not intended to provide individual medical advice. If you are currently using any form of diabetic medication, significant dietary change may necessitate modification or discontinuation of your medication schedule. Consult a qualified medical practitioner for individual direction and medical advice. **