My four year old daughter developed diabetes at the age of 20 months, and we have been checking our two year old son’s blood sugar every so often. Until a month ago he always had levels of 50-110 mg/dl [2.8-6.1 mmol/L], but he has had readings of 172 mg/dl [9.6 mmol/L] and 157 mg/dl [8.7 mmol/L] about two hours after dinner done three weeks apart.

I’m starting to fear that he may be developing diabetes, and I have consulted with his doctor who told me not to worry — these could be normal. I can’t seem to get a definite answer on what range a normal blood sugar should be and what could we be doing to become more informed on possible trials or ruling out that he may be at greater risk at developing diabetes. What would you do next?

Of course you are entitled and are appropriate to be worried. I think your doctor was trying to reassure you. I would like to try to reassure you, too.

Many things can cause the blood sugar to be higher. There is no doubt diabetes is the most concerning, and the one that causes more sustained or recurrent high blood sugar. By definition, diabetes occurs when the serum glucose is greater than 126 mg/dl [7 mmol/L] after at least a 10 hour fast or the value is greater than 200 mg/dl [11.1mmol/L] in a random sample if that person has typical symptoms of increased thirst, urination, etc. The levels must be measured in a laboratory. While meters are very helpful and very adequate to monitor glucose levels in someone with known diabetes, they have an error range that may be 5-10%, depending on the meter. For someone with diabetes if the meter reading is off by 10%, it doesn’t really matter too often (e.g., the glucose is 90 mg/dl [5 mmol/L] or 110 mg/dl [6.1 mmol/L] rather than the 100 mg/dl [5.6 mmol/L] viewed on the meter or it is 270 mg/dl [15 mmol/L] or 330 mg/dl [18.3 mmol/L] when the meter reads 300 mg/dl [16.7mmol/L]. However, if you want to establish a diagnosis, you want as true a value as you can get. Also remember that some meters measure the blood glucose while other meters measure plasma or serum levels. Blood glucose is about 15-20% lower than plasma readings. A normal serum glucose generally is between 60-118 60-120 mg/dl [3.3-6.7 mmol/L].

So, I doubt your child has diabetes, but it is so simple to bring your son to the lab for a fasting glucose level (or even another level two hours later after he eats a hearty, carbohydrate-filled breakfast), that your doctor may do this to reassure everyone. Is your son at risk of diabetes? Yes, because of the inherent genetic risk with his sister, but that does not mean he will! There is about a 5% chance of him developing diabetes. If he has detectable pancreatic antibodies, his chances do increase to about 50%.

DS

[Editor’s comment: See Classification and Diagnosis of Diabetes and DPT-1.

SS]

[Editor’s comment: As already mentioned, testing for diabetes should include blood sugar levels performed by a medical laboratory. The timing of the sample (fasting, random, or postprandial) would influence how high a level is considered abnormal. Another test, the glycosylated hemoglobin, might be used to help confirm a suspected diagnosis of diabetes, but the GHB (also called HbA1c or A1c) is not usually considered as appropriate to make an initial diagnosis. Antibody testing is occasionally done as a screening test in high-risk situations, or as confirmatory of type 1A (autoimmune) diabetes, but is not part of routine testing.

When home glucose testing is done, and seems elevated, it would make the situation more urgent to get lab testing done to confirm the abnormal results.

WWQ]