One point-of-care glucose monitor provided significantly higher and inaccurate glucose measurements. (Image source: Thinkstock)
One point-of-care glucose monitor provided significantly higher and inaccurate glucose measurements. (Image source: Thinkstock)

Most of us assume that point-of-care glucose monitors are accurate.  Dr. Anahat Dhillon, Department of Anesthesiology, UCLA Medical Center, Los Angeles, CA and colleagues describe an instance where measurements using a Roche ACCU-CHEK Inform 1 point-of-care glucose meter were significantly higher than measurements made using laboratory glucose measurements.  This account of point-of care glucose measurement inaccuracy is described in the article “Icodextrin Causing Glucose Meter Error and Severe Hypoglycemia After Deceased Donor Renal Transplant in a Patient Receiving Continuous Ambulatory Peritoneal Dialysis” published in the 15 December 2013 issue of A&A Case Reports.

The patient had end-stage renal disease, and she received continuous ambulatory peritoneal dialysis up to the day before her renal transplant.  All went well during the operation, but afterwards, a point-of-care glucometer showed that her glucose was high. An insulin infusion was started.  Within 24 hours after surgery, she gradually became somnolent.  Not until the second postoperative day was it realized that though her serum glucose was low (20 to 40 mg/dL), her point-of-care glucose meter values were much higher (150 to 200 mg/dL).  The insulin infusion was stopped and a continuous IV 40% dextrose infusion was started.  Unfortunately, the patient never recovered neurologic function.

This is not the first time this has been reported in Anesthesia & Analgesia. Kroll and Maher described a similar incident in 2007.  This case also resulted in permanent neurologic injury and eventual patient death. That case was also characterized by inadequate communication among the health care providers, prompting an editorial “In One Ear and Out the Other: Communication Barriers as a Risk Factor for Critical Incidents” by Wurz and Regli, and cover art emphasizing communication.

With the ACCU-CHEK point-of-care glucose meter, glucose reacts with different enzymes, including glucose dehydrogenase and glucose oxidase, and cofactors, including pyrroloquinolinequinone (PQQ) and nicotine adenine dinucleotide, to create an electric current proportional to sugar concentration.  Icodextrin, a starch-derived, water-soluble glucose polymer that acts as a colloidal osmotic agent, is a component of the peritoneal dialysis system. Its metabolite, maltose, can also react with glucose oxidase.  Icodextrin can stay in the blood up to 14 days after treatment.  Other products also contain icodextrin.

There are other point-of-care glucose meters that are not affected by maltose.  Nevertheless, the lesson to extract from this report is that we should never assume that the monitors we use are infallible, and we should try to know as much as we can about them in addition to why any monitor might provide inaccurate results.