
September 12, 1999
A1c (Glycohemoglobin, HgbA1c), Hypoglycemia
Question from Vermont, USA:
My son is 14 years old, Type 1, diagnosed at age 11, and is on an insulin pump for the last year. He tests 4 times/day and his tests are low, out of his target range. He has no symptoms even at very low readings. In spite of the fact that his basal rate continues to be adjusted lower to accommodate the low tests, his A1c results are higher at each three-month doctor visit. His latest A1c was 14, and the one previous was 12.9 and these results have become a great cause of concern to him. We have checked his numbers against the memory of his tester and they accurately reflect his tests.
Could there be any reason why the A1c is high while the daily blood tests remain low? Do you have any suggestions? How concerned should we be at this point?
Answer:
I can certainly understand your frustration. You may wish to consider having your son’s blood sugar meter checked to assure accuracy. If he indeed has a hemoglobin A1c of 14, his average blood sugar over the past 2-3 months has been well above 250. You didn’t mention your “target range” for his blood sugars but, I would invest in a new meter or have the one you are currently using checked by your diabetes team for accuracy. I’m glad you checked the readings on his meter to see if they agree with his logbook — occasionally, a frustrated adolescent will fabricate the blood sugar readings in their logbook. Also, don’t give up on the insulin pump — it likely has the best chance of decreasing his hemoglobin A1c if he is enthusiastic about having excellent blood sugar control.
MSB
Additional comments from Stephanie Schwartz, diabetes nurse specialist:
There is a discrepancy between the A1c result and the meter’s readings that must be explained. Besides home meter problems, there’s also a slim possibility that your son has an abnormal hemoglobin that might falsely elevate some lab’s A1c levels: the blood can be sent to a second lab to check for this.
Start with a new meter, new strips, and a non-threatening approach. Make sure that you’re not judgemental about high blood sugar levels that you might find if a new meter is used.
However, Dr. Brown is correct in that, teenagers sometimes, in an effort to please doctors and parents, become very adept at getting invalid blood glucose readings (that will record in the meter’s memory).
Teenaged boys at this age have hormones that increase insulin requirements, sometimes 3 times as high as before puberty. My hunch is that he’s overeating (normal behavior for teens), taking extra boluses, and bottoming out.
Take a problem-solving approach with your son and his diabetes team, one step at a time, and you’ll probably find the answer.
SS