January 19, 2003
Diagnosis and Symptoms
Question from Ripon, California, USA:
Yesterday, our four year old son had a routine check-up during which routine urinalysis showed ketones. They decided to do a finger-stick test which was 207 mg/dl [11.5 mmol/L]. After cleaning his finger and one error message, there was some discussion of "Oh, is this the broken one?" He had just finished eating 1 1/2 Pop-tarts (an approximate total of 28 grams of sugar) in the car and waiting room of the doctor's office. Our pediatrician called an endocrinologist, returned to the examining room to tell us my son definitely had diabetes, and ordered a bunch of blood tests. Last night, I called the doctors' office to get the results, and our regular pediatrician had already gone home, but another doctor said my son's laboratory glucose was 122 mg/dl [6.8 mmol/L], which was done approximately two hours after the Pop-tarts. The doctor also said "all the other results look normal." We have another appointment on Monday to do a fasting finger-stick test at the doctors office. We can't sleep or eat, and we just hide our tears from our son. Our son has no symptoms of diabetes except bedwetting (I was a bed wetter until I was about eight years old). He is thin, but not too thin, and we have no family history of diabetes. Do you think my son has diabetes? Did our pediatrician jump the gun on diagnosis? Do you think the Pop-tarts caused the high reading? If the fasting finger-stick test is high, what other tests should I insist on before being comfortable with the diagnosis? Are we just in denial?
A fingerstick blood sugar is a screen and only a screen for the diagnosis of diabetes mellitus. I would avoid “making the diagnosis” based on a fingerstick. There are too many variables: calibration and quality control of the meter; variability of meter accuracy (could be different from a blood test in the lab by near 20%); how appropriately prepped was the finger” (Were his fingers cleaned off well so that you didn’t actually measure the frosting from the Pop-tarts or something else on the finger.
So do I think your doctor “jumped the gun” by saying your child “definitely has diabetes?” Maybe. The correct procedure, following this failed screen, is to do a proper fasting blood test from a vein and run in the laboratory – not just a fingerstick on a meter. Maybe a level from a vein two hours after a meal may be in order, also. However, I will say that a value of 207 mg/dl [11.5 mmol/L] indicates a possible real problem. It may be your son, but it may the meter or the technique. I know you are scared, so get this confirmed for everyone’s satisfaction!