Point-of-Care Glucose Critical Values: A Q-Probes Study Involving 50 Health Care Facilities and 2349 Critical Results

Accuracy of blood glucose measurements in the critical value range is important for properly treating patients with severe hypoglycemia and hyperglycemia.

To evaluate the performance and reliability of point-of-care glucose (POCG) results in the critical value range among multiple facilities.

Q-Probes participants retrospectively collected data from up to 50 POCG results in their critical value range including patient location, type of testing operator, repeat glucose results, and caregiver notification. A repeat measurement at 10 minutes or less that was within 15 mg/dL of initial critical low or 20% of initial critical high value was considered a confirmed result.

Fifty facilities submitted data. Of 2349 critical POCG measurements, 1386 (59.0%) were retested. The median institutional retest rate was 56%. The retest rate was significantly higher when initial results were in the critical low range, P < .001. Although 30 of 50 facilities (60%) had written procedures for retesting, this was not associated with higher retest rates (P = .34). Among 35 facilities that routinely retested critical POCG results, 23 (65.7%) had criteria defined for interpreting results. The median institutional confirmation rate for retested specimens was 81.7%. The median institutional rate for caregiver notification of critical POCG results was 85.7%. Five hundred eighty-six of 1488 critical POCG notifications (39.4%) were done on patients in whom specimens were not retested.

This study shows that POCG results in the critical range may be unreliable because of testing errors that are not recognized from lack of confirmatory testing. In addition, notification of critical POCG results is not consistently performed.