
December 16, 2002
Diagnosis and Symptoms
Question from Belle Center, Ohio, USA:
My grandson has had random blood sugars at home of 230-350 mg/dl [12.8-19.4 mmol/L], and once too high for the meter read, and I even had the meter checked to make sure that was not the problem. However, we have had trouble getting the doctor to believe us because when the fasting at the hospital they are normal. His A1c was 6.1%. Other than voiding and urination, he has no other symptoms Is there anything else I should be insisting on?
Answer:
I understand your concern. Your grandson may have a degree of impaired glucose tolerance. However, there are some pitfalls in what you are describing: The diagnosis of “diabetes” is made under the following conditions:
A fasting serum glucose drawn from a vein and run in a standard laboratory, that is greater than125 mg/dl [mmol/L]. (Some folks say this should be confirmed on two different occasions.);
OR
A random serum glucose drawn from a vein and run in a standard laboratory, that is greater than 200mg/dl [mmol/L] if there are classic symptoms of diabetes
OR
A 2-hour serum glucose drawn from a vein and run in a standard laboratory, that is >200mg/dl [11.1 mmol/L] during a formal glucose tolerance test.
The meters for home use are very good, but they are not accurate enough to diagnose someone with diabetes. There are several reasons which may include, but are not limited to that some meters measure whole blood glucose and others measure plasma/serum glucose. In addition, the meters may have as much as a 20% error rate, i.e a glucose reading that is actually 100 mg/dl [5.6 mmol/L] could read on the meter as low as 80 mg/dl [4.4 mmol/L] or as high as 120 mg/dl [6.7 mmol/L]. For someone who has diabetes, this nuances are usually not critically important, but you want to be as sure as you can before you diagnose someone with diabetes.
The random levels that you get at home on your grandson are so high that we cannot simply flippantly say that is due to meter error, especially if your meter controls and test solutions are accurately measured. but you do want to be completely certain that your grandson’s fingers are perfectly clean and dry before testing. Your grandson wouldn’t be the first to have a spuriously high value due to some residual jelly or candy or Kool-Aid or something on a sticky finger, and you certainly are relaying symptoms of high glucose with increased urination.
Continue to relay your findings to your grandson’s doctor. He may continue to do several fasting glucose levels to confirm or may even do a fasting glucose, have your grandson go eat a hearty, carbohydrate-rich breakfast of pancakes, syrup, orange juice, etc and then repeat the serum glucose. S/he may even go so far as to order a formal glucose tolerance test, although that is often not necessary. He may refer (or you may ask for a referral) to a pediatric endocrinologist.
DS