Diagnosing Diabetes: Understanding The Process

Dr. Fran Cogen Health Pro
  • Upon perusal of the diabetes sections of the MyDiabetesCentral.com, it appears that many people still have questions on just how diabetes is diagnosed. I just answered an inquiry asking if a blood sugar of 80 mg/dl is normal in a 7-year-old child. I thought it might be helpful to discuss diabetes in terms of diagnosis and typical presentations in children.


    In terms of chronic illnesses of childhood, diabetes ranks second to asthma. Recent statistics have indicated that one out of every 400 to 600 children develop type 1 diabetes (insulin dependant diabetes). To possibly develop type 1 diabetes, one must be born with high-risk genes in the area called the Histocompatibility Locus (HLA) on chromosome 6. Another environmental factor, such as a virus or exposure to an unknown trigger, must be present for someone to actually develop type 1 diabetes. Type 2 diabetes, where the body becomes resistant or unable to utilize its own insulin, is on the rise due to familial inheritance, obesity, and lack of exercise in children. The easy availability of fast food, as well as decreased physical exercise in school, has contributed to this epidemic as well.

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    In children, diabetes is often diagnosed after typical presentations to the primary care physician. The first presentation is usually with symptoms of increased thirst, drinking, urination, and appetite. There is often an associated weight loss due to the body's inability to metabolize glucose and reliance on fat and muscle stores for energy. These symptoms may occur over days or weeks and if allowed to continue over time may tip the child over into diabetic ketoacidosis in which dangerous acids build in the blood stream requiring admission to a pediatric intensive care unit. Keep in mind that diabetic ketoacidosis may occur in presentations of both type 1 and type 2 diabetes. Your primary care physician will obtain a urine sample based on the above history and determine if there is the presence of glucose or ketones. If glycosuria (glucose in the urine) is confirmed, your doctor will take a blood test to measure blood glucose levels. The second presentation is often a surprise diagnosis in which routine urine samples positive for glucose are obtained at the time of a school or sports physical. In these situations, the child or adolescent is often asymptomatic. At this time, there are three ways to diagnosis diabetes based on the American Diabetes Association and American College of Endocrinologists guidelines. A fourth method, using an hb A1c is currently under discussion.


    Diagnosising Diabetes:

    1. Random blood sugar >/= of 200 mg/dl along with symptoms of increased drinking, urination, thirst, hunger, and weight loss. Not all symptoms need be present.
    2. Fasting blood sugar (blood sugar upon awakening) > 126 on two separate mornings.
    3. Oral glucose tolerance test in which 75 grams of carbohydrate are ingested and blood sugars >200 mg/dl are obtained one to two hours afterwards.
    4. Hb A1c> 6.5 is currently under discussion in the diabetes community. The ADA published a scholarly article after its June 2009 scientific sessions indicating that a hb A1C > 6.5 may be a useful tool to diagnose diabetes.

    Blood glucose ranges:


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    A normal blood sugar is based on the time it is obtained (whether one is fasting or after eating). Impaired glucose tolerance or "pre-diabetes" is diagnosed if:

    1. Fasting blood sugar is between 100-126 mg/dl.
    2. Oral glucose tolerance test in which 1-2 hour reading is between 140-200 mg/dl.

    Generally "prediabetes" occurs in people at risk for the development of type 2 diabetes and is not applicable in patients who develop type 1 diabetes due to the presence of insulin in type 2 patients and lack thereof in children and teens with type 1 diabetes.


    In children and teens with known diabetes, your diabetes team will provide goal ranges of blood sugars based on your age. Younger children (<5 years) are usually given higher blood sugar ranges and young adults given adult ranges. Typical goal blood sugar ranges depending on age groups (keep in mind that your diabetes team may specify different ranges and that is ok)


    1. Under 5 years of age:             80-200 mg/dl

    2. Five years and older children:   70-180 mg/dl

    3. Adolescents and young adults: 70-120-180 mg/dl (depending on personal goals).


    Hypoglycemia is generally defined as blood sugars < 70 mg/dl. Keep in mind that one may be asymptomatic even with a blood sugar 40 mg/dl (lower than 70) on one occasion and may have major hypoglycemic symptoms with blood glucose of 65 mg/dl.


    If there are any further questions regarding the diagnosis of diabetes or discussion of blood glucose targets, etc., please let me know and I will answer in the comments section.



Published On: October 13, 2009