CLINICAL CASE FROM 2009
JF, a 64-year-old man with a 30-year history of type 2 diabetes managed with basal and rapid-acting prandial insulin, started peritoneal dialysis using icodextrin dialysis solution. Since starting dialysis, JF has experienced persistently elevated blood glucose readings (in the high 200 mg/dL to high 300 mg/dL range) using his Accu-Chek Compact glucometer purchased in 2008. In response, JF has been taking higher doses of rapid-acting insulin with meals and for correction, with two-to-three-hour postprandial blood glucose readings persistently elevated (in the high 200s). JF has no fevers, chills, abdominal pain, or other signs/symptoms of infection. Urine ketone testing is negative.
Yesterday, JF’s pre-lunch blood glucose registered at 380 mg/dL on his glucometer, and he took a dose of rapid-acting insulin that was double what he would have taken prior to starting dialysis. About 90 minutes after lunch, JF felt weak and diaphoretic and became unresponsive, with seizure-like activity. His wife called the paramedics; when they arrived, JF’s fingerstick glucose level was 28 mg/dL (using a One Touch Ultra glucometer).
JF was treated acutely with IV dextrose and then transported to a nearby hospital. During his hospitalization, his blood glucose level was maintained in the mid-100 to high-200 mg/dL range, with approximately 50% lower doses of rapid-acting insulin with meals. Hospital work-up revealed no evidence of secondary causes of hyperglycemia. EEG was negative.
Further investigation determined that JF’s Accu-Chek Compact glucometer used GDH-PQQ methodology, which is unable to distinguish between the blood glucose level and the maltose metabolite of icodextrin contained in the peritoneal dialysis solution—leading to falsely elevated glucose results. JF switched to a different glucometer that did not use test strips containing the GDH-PQQ method, allowing for more accurate blood glucose readings and no recurrent episodes of severe hypoglycemia.
Continue for biochemistry of glucose measurements >>