Abstract and Introduction
Purpose: The precision and accuracy of two blood glucose meters were evaluated using finger and forearm blood samples.
Methods: Duplicate blood glucose measurements on the same forearm and finger as venipuncture were performed with the FreeStyle Flash and the One Touch Ultra. Accuracy was assessed by error-grid analysis and the number of values within 10% of the laboratory reference value. Precision was determined by calculating the absolute mean percent differences in glucose values between the first and second fingers and forearm test results. Forearm testing success was defined as an accurate glucose reading obtained with one lance.
Results: A total of 100 patients completed the study; 93% had diabetes and 53% were female. Patients mean ± S.D. age was 63 ± 12 years, and glucose measurements ranged from 69 to 354 mg/dL. All finger-stick samples fell within error-grid zones A and B; 72% and 57% of FreeStyle Flash and One Touch Ultra values fell within 10% of the laboratory reference values, respectively (p = 0.027). Forearm samples were successfully obtained in 99 and 74 patients using the FreeStyle Flash and One Touch Ultra (p < 0.001), with 64 and 36 samples, respectively, falling within 10% of the laboratory reference values (p = 0.035). There was no difference in meter precision.
Conclusion. The FreeStyle Flash and the One Touch Ultra are precise glucose meters; however, the FreeStyle Flash was associated with greater accuracy. Success rates of forearm glucose sampling were significantly greater when the FreeStyle Flash meter was used.
Self-monitoring of blood glucose (SMBG) is recognized as an integral adjunctive tool for diabetes management.[1] SMBG allows for real-time glucose measurements, enabling patients and clinicians to adjust diabetes regimens and reach glycemic targets. Intensive treatment of type 1 diabetes mellitus, with an emphasis on 4-point SMBG (e.g., pre-prandial and postprandial glucose monitoring), has been shown to significantly lower the risk of diabetes-related microvascular complications by 5076%.[2] Several other studies have further proven that SMBG plays a crucial role in glycemic control and subsequent lowering of glycosylated hemoglobin (HbA1c).[35] A recent meta-analysis found that SMBG is associated with significant decreases in HbA1c levels in patients with type 2 diabetes mellitus.[6] SMBG is endorsed by specialty organizations to optimize glycemic control.[7,8] Current recommendations by the American Diabetes Association propose that SMBG be performed at least three times daily for patients with type 1 or gestational diabetes and as often as clinically necessary for patients with type 2 diabetes to reach glycemic goals.[7] A recent global consensus conference of diabetes experts recommended that SMBG be used by all patients with diabetes.[9]
One reason patients do not perform SMBG is the physical and psychological discomfort associated with the traditional finger-stick method of blood sampling.[1012] Glucose-monitoring devices are available that offer patients the choice of using either the traditional finger-stick method or a less painful alternative testing site, such as the forearms, palms, or thighs, to obtain blood samples.
When SMBG is indicated, meter accuracy must be ensured. Clinical guidelines recognize that accuracy depends not only on the user but the instrument as well. Several criteria have been recognized by professional or regulatory agencies as reasonable standards for the testing accuracy of glucose monitors. These criteria range from a variation of no more than 20% from the laboratory reference value (recommended by the National Committee for Clinical Laboratory Standards)[13,14] to a deviation of 5% from the reference value (proposed by the American Diabetes Association).[1] Clinical trials measuring meter accuracy have most frequently used the International Organization for Standardizations (ISO) accuracy criterion of <10% deviation from the laboratory reference value.[15,16] Studies evaluating SMBG generally examine finger-stick measurements.[17] Few studies have assessed the accuracy of SMBG using an alternative site,[1820] even though forearm glucose results are considered comparable to finger-stick readings as long as blood glucose levels are not rapidly changing.[21]
Two of the most commonly used alternative-site glucose monitors are the FreeStyle Flash (Abbott Diabetes Care, Alameda, CA) and the One Touch Ultra (LifeScan, Milpitas, CA). To date, no direct comparisons of the FreeStyle Flash and the One Touch Ultra have been published. The primary objective of this study was to compare the accuracy (correctness) and precision (exactness of replication) of finger and forearm blood glucose measurements obtained using the two meters to a laboratory reference value obtained via venipuncture. The secondary objective was to evaluate the relationship of any variation between forearm glucose measurements (compared with finger-stick or venous results) with regard to the time of the patients previous meal. The third objective was to compare the success rates of forearm meter testing between the two meters.
Am J Health Syst Pharm. 2006;63(15):1411-1416. © 2006 American Society of Health-System Pharmacists
Cite this: Precision and Accuracy of Two Blood Glucose Meters: FreeStyle Flash Versus One Touch Ultra - Medscape - Aug 01, 2006.
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