Evaluation of hematocrit bias on blood glucose measurement with six different portable glucose meters

Abstract

Introduction: Measurement and monitoring of blood glucose levels in hospitalized patients with portable glucose meters (PGMs) is performed widely and is an essential part of diabetes monitoring, despite the increasing evidence of several interferences which can negatively bias the accuracy of measurements. The purpose of this study was to evaluate the eff ect of the hematocrit on the analytical performances of diff erent PGMs as compared with a reference laboratory assay. Materials and methods:The eff ect of various hematocrit values (~0.20, ~0.45 and ~0.63 L/L) were assessed in three whole blood specimens with diff erent glucose concentration (~1.1, ~13.3, and ~25 mmol/L) by using six diff erent commercial PGMs. The identical samples were also tested with the laboratory reference assay (i.e., hexokinase). The percentage diff erence from the laboratory assay (%Diff ) was calculated as follows: % Diff = average PGM value -value from laboratory assay x 100 / value from laboratory assay. Results: The %Diff of the six diff erent PGMs were rather broad, and comprised between 56.5% and -34.8% in the sample with low glucose concentration (~1.1 mmol/L), between 40% and -32% in the sample with high glucose concentration (~13.3 mmol/L), and between -50% and 15% in the sample with very high glucose concentration (~25 mmol/L), respectively. It is also noteworthy that a very high hematocrit value (up to 0.63 L/L) generated a remarkable negative bias in blood glucose (-35%) as measured with the laboratory assay, when compared with the reference sample (hematocrit 0.45 L/L). Conclusion:The results of this analytical evaluation clearly confi rm that hematocrit produces a strong and almost unpredictable bias on PGMs performances, which is mainly dependent on the diff erent type of devices. As such, the healthcare staff and the patients must be aware of this limitation, especially in the presence of extreme hematocrit levels, when plasma glucose assessment with the reference laboratory technique might be advisable.

Comparative Performance Assessment of Point-of-Care Testing Devices for Measuring Glucose and Ketones at the Patient Bedside

“…The influence of hematocrit on the accuracy of glucose measurements of Optium Freestyle has previously been reported. 23,24 In this study the BHB device also was affected, resulting in the characteristic interference pattern seen with glucose measurements, that is, falsely elevated BHB values when hematocrit is low and vice versa ( Figures 3A, 3B). Although the Accu-Chek strip technology has recently been modified, there is still evidence of an influence of hematocrit as previously reported.…”

“…38 The specificity deficiencies for some of the POC glucose methods evaluated in this analytical study parallel those of similar studies, and there is evidence emerging of the direct consequences of these deficiencies on clinical decision making. 23,24 However, although this analytical study also demonstrated that hematocrit and ascorbic acid can influence the accuracy of BHB results, the clinical significance and relevance of this to patient decision making require further investigation. In addition, we assessed only a small number of known glucose interference factors, and further investigation of other known factors may help determine the extent of the inaccuracy problem.…”

Risk of Death Associated With Reversion From Prediabetes to Normoglycemia and the Role of Modifiable Risk Factors

“…Of note, the implications of impaired fasting glucose and impaired glucose tolerance for cardiovascular outcomes were similar . Because an individual’s FPG level changes over time, a potential measurement error in FPG assessment may lead to overestimation of the number of participants who reverted to normoglycemia . Second, similar to any observational study, although we adjusted for potential confounding factors, we could not completely exclude reverse causality or unmeasured confounders.…”

Estimated Risk for Insulin Dose Error Among Hospital Patients Due to Glucose Meter Hematocrit Bias in 2020

“…The influence of hematocrit on measurement and reporting of glucose levels by point-of-care testing devices has been an important focus of clinicians, laboratorians, international standards organizations, and medical device manufacturers for the past 20 years. [2][3][4][5][6][7][8]19,20 The decision to convert whole blood measurements into plasma equivalent glucose concentrations, rendering point-of-care device results more consistent with central laboratory results, 9 was clinically pragmatic, but analytically cryptic. A hematocrit mean level of 43% is anticipated in many healthy populations.…”

“…Overwhelming evidence has confirmed that patient-specific factors, such as hematocrit variation, can substantially alter glucose meter results and lead to significant intermeter variability. [2][3][4][5][6][7] This hematocrit effect may vary across glucose meter brands, leading to a complex spectrum of published glucose meter performance outcomes. While these hematocrit effects are well described in relation to glucose meter values, the downstream effect upon insulin-dosing decisions, the patient-centered and clinically relevant outcome, is seldom considered.…”