Turkish Journal of Endocrinology and Metabolism, (2005) 4 : 115-118 ORIGINAL ARTICLE Blood Glucose Monitoring Performance of “Roche Accu-Check Go” Glucometer Device at Moderately High Altitude Habib Bilen* Alpaslan Kılıçaslan** Güngör Akçay* İlyas Çapoğlu* * University of Atatürk,School of Medicine, Department of Internal Medicine, Division of Endocrinology, Erzurum, Turkey ** University of Hacettepe, School of Medicine, Department of Internal Medicine, Ankara, Turkey To evaluate the performance of Roche Accu-check glucometer device compared to reference laboratory measurement in moderately high altitude. Research Design and Methods: Fasting blood glucose measurements were made simultaneously by Accu- check go glucometer device and standard laboratory methods in a group of 204 male and female patients residing in Erzurum, a province in Eastern Turkey with an altitude of 2000 meters. Majority of patients had type 2 diabetes. Results: Average fasting blood glucose levels measured with Accu-check go (101.5; 71-456) were lower compared to reference values (102.5; 69-456), with no statistically significant difference. Also, there were no significant differences between the two methods with regard to measured values below and above the threshold level of 126. The type of diabetes and gender had no effect on measurements. Conclusions: Slightly lower glucose levels observed with Accu-check go at a moderately high altitude of 2000 meters can be explained on the basis of oxidoreductase method used. However, absence of any significant difference suggests that the ability of Accu-check go to detect hypoglycemia at this altitude at an early stage is not compromised. Keywords: Accu-check go, altitude, blood glucose monitoring system Introduction conducted at the Endocrinology Unit, Atatürk University, Erzurum, Turkey. Erzurum with an Hypoglycemia is a major complication in the altitude of greater than 2000 meters is a popular treatment of diabetes. Self-monitoring of blood winter sports center with a long winter season. glucose (SMBG) is an important tool both for the improved glucose control and in the prevention of hypoglycemia (1). SMGB allows self-monitoring Research Design and Methods of blood glucose when used appropriately. A total of 204 patients between 19 and 71 years of However the performance of these devices are age mostly residing in Erzurum were included in affected by a number of factors including altitude, this study. Majority of the patients had type 2 temperature, oxygen saturation of blood, low diabetes. Blood sampling for fasting blood glucose atmospheric pressure, humidity, and a change in measurements was done in the morning hours at hematocrit value, as well as user-related factors (2-7). the laboratory of Endocrinology Unit by nurses. The room temperature was approximately 20°C. In this study, our objective was to evaluate the Capillary blood glucose was measured by “Roche performance of Roche Accu-check glucometer Accu-check go (serial no: GJ0492680, Roche, device compared to reference laboratory measure- Mannheim, Germany)” glucometer device, which ments in moderately high altitude. The study was utilizes a photometric measurement technique based on oxidoreductase method. Approximately 1.5 μl of full blood (fresh capillary or venous, Li- or Correspondence address: NH4-heparin or EDTA) is required for measure- Habib Bilen University of Atatürk,School of Medicine, ments by Accu-check go, and the reading is Department of Internal Medicine, Division of Endocrinology, available in 5 seconds. A venous blood sample was Erzurum, Turkey Tel : +90 442 236 12 12 drawn quickly thereafter for laboratory measure- E-mail : [email protected] ment of plasma glucose with an Olympus AU 2700 115 ORIGINAL ARTICLE analyzer (serial no: 1110268). Barometric pressure cordance between the two measurements was and humidity were constant. Performance of the assessed with kappa constant and the concordance glucometer device was determined by comparison rate was 47%, which is depicted by Bland & with the standard laboratory methods. Patients with Altman plots (Figure 1). As can be seen from the diabetes complication were excluded from the figure, the concordance rate for values below 126 study. Patients who were treated with medications is higher compared to those above it, although chi- that can affect blood glucose levels (e.g. steroids), square test revealed no statistical difference patients who had anemia (serum hematocrit <40%) between the two measurement methods for values and patients who are receiving medications that below and above 126 (p > 0.05). influence glucose measurement by glucometer In Table 2, the relationship between gender and the (e.g. aspirin, vitamin C) were also excluded. two measurement methods is shown. There were Informed consent was obtained from all patients. 124 female and 80 male patients in the study. The study protocol was approved by the local There were no differences between the two Ethics Committee-Institutional Board, and was methods in terms of gender (p > 0.05). carried out in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki as Majority of the patients had type 2 diabetes (Table 1), revised in 2000. and the effect of the type of diabetes on measu- rements was investigated. Accu-check go and Statistical analysis reference measurements did not differ significantly with respect to the type of diabetes (p > 0.05) Wilcoxon pairwise two-sample test was used due (Table 3). to the abnormal distribution of data. Instead of mean, median values (minimum and maximum) Table 1. Demographic characteristics of patients. were used. Kappa constant was used to assess the AGE concordance between the two measurement met- Male, y (range) 49.5 (21-71) hods with regard to the values observed below and Female, y (range) 45.0 (19-66) above the threshold level of 126. Statistical SEX analysis were performed with SPSS 11.5 and Male, n (%) 80 (39.2) medcalc 6.16. Female, n (%) 124 (60.8) Results TYPE of DM Type 1, n (%) 33 (16.2) The mean age was 46 years (19-71 y). Demo- Type 2, n (%) 171 (83.8) graphic characteristics of the patients are shown in Table 1. The average blood glucose levels Female measured with Accu-check go and reference Type 1, n (%) 20 (16.1) laboratory were 101.5 (71-456) and 102.5 (69-456) Type 2, n (%) 104 (83.9) mg/dl, respectively. The blood glucose values of Male the overall patient group were divided into two: Type 1, n (%) 13 (16.3) those below and above 126 mg/dl. The con- Type 2, n (%) 67 (83.8) Table 2. Comparison of two methods for different sexes. Measurement Gender Median (Min-Max) P value method Reference 100,0 (75,0-444,0) 0,801 (ns) Male (n=80) Accu-check 104,5 (74,0-456,0) Reference 102,5 (71,0-456,0) 0,893 (ns) Female (n=124) Accu-check 101,0 (69,0-432,0) Reference 102,5 (69,0-456,0) Total (n=204) Accu-check 101,5 (71,0-456,0) ns: not significant, P<0,05 is considered significant 116 ORIGINAL ARTICLE Table 3. Comparison of two methods for different diabetes types. Measurement DM Type Median (Min-Max) P value method Reference 111,0 (83,0-450,0) 0,815 (ns) DM Type 1 (n=33) Accu-check 119,0 (81,0-397,0) DM Type 2 Reference 100,0 (71,0-456,0) 0,889 (ns) (n=171) Accu-check 101,0 (69,0-456,0) Reference 102,5 (69,0-456,0) Total (n=204) Accu-check 101,5 (71,0-456,0) ns: not significant, P<0,05 is considered significant 400 the oxidase method at different altitudes and found lower values with increasing altitude (11). 300 +1.96 SD In this study, although slightly lower glucose 200 238,0 values were observed with Accu-check go, the 100 difference was not significant. Since Accu-check Mean 0 go is based on an oxidoreductase method, lower -5,5 -100 values can be explained on the basis of decreased Refferance - Accu_check Refferance - partial oxygen pressure at moderately high alti- -200 -1.96 SD tudes, though the difference was negligible. -249,0 -300 We also evaluated whether Accu-check go -400 measurements differ for values below and above a 50 100 150 200 250 300 350 400 AVERAGE of Refferance and Accu_check threshold level of 126 mg/dl. In contrast to the previous study in which blood glucose levels were Figure 1. Bland & Altman plot diagram of blood glucose values for measured in different groups (8), we found no two measurement methods (within +/- 1.96 standard significant difference. deviation) Factors that can influence the performance of glucometer devices include inadequate exposure to Conclusion capillary blood drop, timing errors, and user errors In this study, we evaluated the performance of (12). In order to minimize the effect of such Roche Accu-check go glucometer device at a factors, glucometer measurements were performed moderately high altitude and found no significant by trained personnel. On the other hand, possible difference between measurements made with effect of other variables such as hematocrit Accu-check go and reference laboratory (p > 0.05). changes, altitude, ambient temperature, humidity, In contrast with a previous study, Accu-check go hypotension, hypertriglyceridemia, hypoxia and values were lower compared to laboratory values low atmospheric pressure cannot be ruled out (8). However in that study, the effect of altitude was completely. In order to eliminate such confounding not assessed. Capillary blood glucose measurement factors patients with a hematocrit value below 40, devices (BGMs) have been shown to produce patients with hypotension, and patients who are lower values under laboratory conditions with being treated with medications that can have an constant humidity and temperature simulating impact on glucose measurements were excluded altitudes greater than 2000 meters (4), in very high from the study.