If the Numbers Don't Fit... Discrepancies Between Glucose Meter Readings and Hemoglobin A1c Reveal Stress of Living With Diabetes

Abstract

C.S. is a 17-year-old girl who has had type 1 diabetes for 14 years. During early childhood, her hemoglobin A1c (A1C) was usually < 8%, and her mother performed most of her diabetes care tasks. As she entered adolescence, C.S. took on more of the diabetes care herself and shared less of the management responsibilities with her mother. She used glargine once a day and lispro multiple times each day. She used a formula to calculate her insulin dose based on her carbohydrate intake (1 unit for each 10 g of carbohydrate eaten) and a correction factor for high glucose concentrations (1 unit for each 50 mg/dl above 100 mg/dl). She had been using this plan for 2 years. At a recent diabetes clinic visit, she reported being satisfied with her glycemic control, and the average on her glucose meter memory was 147 mg/dl. In downloading her meter records, her providers noted at least 3-4 glucose tests each day, almost all within the 70-180 mg/dl range. Her A1C measured on the same day, however, was 9.4% (normal 4-6%). After lengthy discussion with her about this discrepancy, C.S. admitted that she had used control solution in place of her own blood for most of the glucose meter checks. Control solution is part of the glucose meter kit and is used to confirm the accuracy of the machine and test strips. Results using control solution usually are close to the normal range (the expected range is indicated on the control solution bottle) as long as the machine and test strips are working properly. C.S. complained of being tired of dealing with her diabetes and said she found it “exhausting” to meet the expectations of her family and diabetes team. Her mother, who accompanied her …