Effect of non-glucose sugars and haematocrit on glucose measurements with Roche Accu-Chek Performa glucose strips (original) (raw)
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Comparison of glucose determinations on blood samples collected in three types of tubes
Annals of clinical and laboratory science, 2013
Because of the metabolism of serum glucose in collection tubes containing blood samples, serum glucose levels may be found to decrease over time. Several types of collection tubes have been designed to, at least partially, block glucose metabolism by red blood cells in blood collection tubes that may not be analyzed immediately after blood collection. These include red-top collection tubes with serum separator, grey-top tubes with a fluoride glycolysis inhibitor, and heparin-containing green-top tubes which prevent clot formation. As part of a quality assurance project, we investigated whether glucose levels differed in the three tube types from each of 18 volunteers on a prolonged standing of 4 hours. We then determined the glucose concentrations of all three tubes from each of the 18 volunteers. We used refrigerated samples over a five-day period to determine if the initial values were reproducible. Surprisingly, after standing for four hours at room temperature, we found that the...
IP Innovative Publication Pvt. Ltd., 2017
Context: Self-monitoring of glucose levels with a hand held glucometer is very popular among the diabetic patients and doctors as it is less traumatic and gives instant results. Capillary blood samples are commonly used for self-monitoring in comparison to venous plasma sample which are used in the diagnostic laboratories. Aims: This study was done to compare the glucose levels of a capillary blood sample determined by a glucometer with the glucose level determined by Glucose Oxidase Peroxidase (GOD-POD) method using a venous plasma sample. Setting and Design: This experimental study was carried out at Rohilkhand Medical College and Hospital. Methods and Material: Two hundred patients were randomly selected for the study. Their venous blood samples were collected in a fluoride containing blood collection tube. The plasma obtained was subjected to GOD-POD test. Simultaneously their capillary blood glucose was also determined by a glucometer. Statistical analysis used: The data collected was analyzed using SPSS 17.0 version. Data was expressed as mean ± SD. Significance of mean was analyzed using paired t test. P value < 0.05 was considered significant. Result: Glucose levels determined by a glucometer and GOD-POD method showed very good correlation (r=0.958; p<0.001). However, at very high and low glucose levels, the glucometer significantly under estimated (p=0.014) and overestimated (p<0.001) the glucose levels respectively. Conclusion: Although glucometers are effective for routine monitoring of glucose levels, they should be used cautiously in emergency conditions.
Annals of Clinical Biochemistry, 2010
False elevations of plasma lactate dehydrogenase (LDH), potassium and aspartate aminotransferase (AST) have been described, in relation to haemolysis, occurring most often by mechanical release during phlebotomy or specimen processing. We present the cases of two leukaemic patients with severe hyperleukocytosis for whom LDH, potassium and AST were dramatically but falsely elevated. This false elevation was not caused by haemolysis but could be related to white cells lysis during transport through a pneumatic transportation system, enhanced by a specific fragility of leukaemic cells. Interestingly, this interference almost completely disappeared when serum rather than plasma was used, or when leukocytosis came back to normal. This work is meant to alert clinicians to the risks of errors in LDH, potassium and AST in leukaemic patients and suggest what precautions to take.
Nephron Physiology, 2014
Background: Hyperkalemia is a common medical emergency that may result in serious cardiac arrhythmias. Standard therapy with insulin plus glucose reliably lowers the serum potassium concentration ([K + ]) but carries the risk of hypoglycemia. This study examined whether an intravenous glucose-only bolus lowers serum [K + ] in stable, nondiabetic, hyperkalemic patients and compared this intervention with insulin-plus-glucose therapy. Methods: A randomized, crossover study was conducted in 10 chronic hemodialysis patients who were prone to hyperkalemia. Administration of 10 units of insulin with 100 ml of 50% glucose (50 g) was compared with the administration of 100 ml of 50% glucose only. Serum [K + ] was measured up to 60 min. Patients were monitored for hypoglycemia and EKG changes. Results: Baseline serum [K + ] was 6.01 ± 0.87 and 6.23 ± 1.20 mmol/l in the insulin and glucose-only groups, respectively (p = 0.45). At 60 min, the glucose-only group had a fall in [K + ] of 0.50 ± 0.31 mmol/l (p < 0.001). In the insulin group, there was a fall of 0.83 ± 0.53 mmol/l at 60 min (p < 0.001) and a lower serum [K + ] at that time compared to the glucose-only group (5.18 ± 0.76 vs. 5.73 ± 1.12 mmol/l, respectively; p = 0.01). In the glucose-only group, the glucose area under the curve (AUC) was greater and the insulin AUC was smaller. Two patients in the insulin group developed hypoglycemia. Conclusion: Infusion of a glucose-only bolus caused a clinically significant decrease in serum [K + ] without any episodes of hypoglycemia.
Biochemia Medica, 2011
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.
Accuracy of the HemoCue Portable Glucose Analyzer in a Large Nonhomogeneous Population
Diabetes Technology & Therapeutics, 2001
Several studies have reported inconsistent results between HemoCue ® (HC) whole blood glucose measurements compared to plasma glucose. We selected a large patient population with diverse pathologies and healthy volunteers to evaluate HC. For this comparison, whole blood glucose concentration was measured using HC and referenced to laboratory plasma glucose. The population (n 5 512) included healthy volunteers, diabetics, and patients with heart failure, liver failure, renal failure, renal and liver transplant, and other chronic diseases. Patients were on a wide variety of medications, vitamins, and food supplements. Venous blood samples were collected in tubes containing potassium oxalate and sodium fluoride. Comparison of the results was made using the method of Bland and Altman and ANOVA at three selected glucose ranges. The glucose measurement ([HC 1 laboratory]/2) ranges were 24-75, 76-129, and 130-404 mg/dL. A positive bias for all three glucose ranges was observed: 38 6 17 mg/dL for the high glucose group compared to 24 6 9 mg/dL and 22 6 10 mg/dL for the middle and low groups, respectively. In the high glucose group 90% of the values were within 10% (R 5 0.97) of the laboratory reference values compared to 81% and 55% in the normal and low glucose groups, respectively. HC glucose measurements were generally within two SD from the laboratory plasma reference. HC consistently yielded lower whole blood glucose measurements than plasma with the largest differences seen in the low glucose range (29%). HC measured more consistently at the higher glucose concentrations and was 16% lower than plasma, although the mean absolute error was highest for that range. No significant effects in the bias could be attributed to disease while possible effects from instrument modifications by the manufacturer remain uncertain.
Laboratory Medicine, 2009
Hemolysis, or the rupture of the red blood cell membrane, causes the release of hemoglobin and other internal components into the surrounding fluid. It has long been recognized as a source of error in a variety of chemical analyses. 1 Hemolyzed specimens are a relatively frequent occurrence in laboratory practice, having a prevalence reported to be as high as 3.3% of all routine samples sent to a clinical laboratory and accounting for nearly 60% of rejected specimens. Hemolysis causes factitious hyperkalemia appearing to be approximately linearly dependent on the final concentration of blood cell lysate in the specimen. Some formulas, based on the relative distribution of potassium between serum and erythrocytes, have been proposed as a means of making a quantitative correction of the effect of hemolysis through measurements of serum hemoglobin. 4,5 These correction factors were obtained by multiplying the hemoglobin concentration by the slope obtained from a linear regression analysis between the bias observed for potassium at the relative free serum hemoglobin concentration. 4,6 Nevertheless, as reported in the literature, these factors are heterogeneous. This could be due to the complexity of preparing physiological hemolytic solutions to assess the inter-individual red cell hemoglobin concentration. Because the mean concentration of hemoglobin in the red cells differs among individuals, the quantity released into the serum as a result of hemolysis will also be different and is difficult to correlate to the total potassium released by means of a "common" correction factor.