My two year daughter has been experiencing low blood sugars (51 mg/dl [2.8 mmol/L] at a lab) and her three-hour glucose tolerance test was remarkable with a low of 76 mg/dl [4.2 mmol/L] and a high of 84 mg/dl [4.7 mmol/L], but her doctors are unable to make a good diagnosis at this time. Should she be tested for other causes unrelated to reactive hypoglycemia? Diet control does not seems to have any effect on her lows at this time. Any suggestions are very much needed at this time.

I gather from your letter that your daughter does not have diabetes mellitus, and I presume that she is otherwise healthy and not receiving any medication, food supplement, or health food supplement/vitamins. You do not indicate how long she has been experiencing low-glucose values (hypoglycemia) or what, if any symptoms she has.

My approach to an evaluation might hinge on when and how often the symptomatic hypoglycemia was occurring and how reliable the documentation was. A “normal” blood glucose is between 60-125 mg/dl [3.3- 6.9 mmol/L]. A glucose value of 51 mg/dl [2.8 mmol/L] is disturbing, but I would want to be certain that the sample was analyzed promptly after it was drawn because blood samples that “sit out” for awhile before being analyzed will have lower and lower glucose in them as the red blood cells consume the glucose for energy. If this done in a “send-out commercial lab” (rather than say, in the local hospital lab), I might be suspicious of the result of 51 mg/dl [2.8 mmol/L]

You do not indicate the specifics of the glucose tolerance test, but I am not concerned with the values that you gave, and these values do not raise the diagnosis of so-called reactive hypoglycemia in my mind.

There are a number of possible causes — many not-so-worrisome and some very significant — of hypoglycemia. Some of these can be screened for with easy one-time blood draws (e.g., checking ammonia, liver function tests) while others are best screened for during a time of confirmed hypoglycemia (e.g., various hormone imbalances), while others must be assessed much more formally during a supervised state of prolonged fasting or even “challenge tests.”

If your daughter has not been referred to a specialist in this (either a pediatric endocrinologist or metabolic specialist), this may be reasonable — again depending on the severity/frequency of the presumed hypoglycemia. Keep in mind that other conditions may mimic hypoglycemia.

DS