The effect of the haematocrit value on the determination of glucose levels by reagent‐strip methods

Barreau, P.; Buttery, J E

doi:10.5694/j.1326-5377.1987.tb133457.x

Cited by 33 publications

(14 citation statements)

References 5 publications

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“…In reagent strip tests, it is probably the nature of the barrier, preventing red cell entry into the reagent layer, which determines the extent of the effect. Strip tests are particularly susceptible to the effect of haematocrit owing to discoloration of the test pad, resistance to washing or wiping before reading and nally impedance of plasma diffusion into the test pad (25,26). The Advantage system has previously been shown to function independently of haematocrit (10).…”

Section: Discussionmentioning

confidence: 99%

Comparison of EML 105 and Advantage analysers measuring capillary versus venous whole blood glucose in neonates

McNamara

Sharief

2001

Acta Paediatrica

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McNamara PJ, Sharief N. Comparison of EML 105 and Advantage analysers measuring capillary versus venous whole blood glucose in neonates. Acta Paediatr 2001; 90: 1033-1041. Stockholm. ISSN 0803-5253Aim: Near-patient blood glucose monitoring is an essential component of neonatal intensive care but the analysers currently used are unreliable and inaccurate. The aim of this study was to compare a new glucose electrode-based analyser (EML 105) and a non-wipe re ectance photometry method (Advantage) as opposed to a recognized laboratory reference method (Hexokinase). We also investigated the effect of sample route and haematocrit on the accuracy of the glucose readings obtained by each method of analysis. Methods: Whole blood glucose concentrations ranging from 0 to 3.5 mmol/l were carefully prepared in a laboratory setting and blood samples from each respective solution were then measured by EML 105 and Advantage analysers. The results obtained were then compared with the corresponding plasma glucose reading obtained by the Hexokinase method, using linear regression analysis. An in vivo study was subsequently performed on 103 neonates, over a 1-y period, using capillary and venous whole blood samples. Whole blood glucose concentration was estimated from each sample using both analysers and compared with the corresponding plasma glucose concentration estimated by the Hexokinase method. Venous blood was centrifuged and haematocrit was estimated using standardized curves. The effect of haematocrit on the agreement between whole blood and plasma glucose was investigated, estimating the degree of correlation on a scatterplot of the results and linear regression analysis. Results: Both the EML 105 and Hexokinase methods were highly accurate, in vitro, with small proportiona l biases of 2% and 5%, respectively. However, in vivo, both study analysers overestimated neonatal plasma glucose, ranging from at best 0.45 mmol/l (EML 105 venous) to 0.69 mmol/l (EML capillary). There was no signi cant difference in the agreement of capillary (GD = 0.12, 95% CI. {¡0.32, 0.08}, p = 0.2) or venous samples (GD = 0.05, 95% CI. {0.09, 0.19}, p = 0.49) with plasma glucose when analysed by either study method (GD = glucose difference between study analyser and reference method) However, the venous samples analysed by EML 105 estimated plasma glucose signi cantly better than capillary samples using the same method of analysis (GD = 0.24, 95% CI. {0.09, 0.38}, p < 0.01). The relationship between haematocrit and the resultant glucose differences was non-linear with correlation coef cients of r = ¡0.057 (EML 105 capillary), r = 0.145 (EML 105 venous), r = ¡0.127 (Advantage capillary) and r = ¡0.275 (Advantage venous). There was no signi cant difference in the effect of haematocrit on the performance of EML 105 versus Advantage, regardless of the sample route.Conclusion: Both EML 105 and Advantage overestimated plasma glucose, with no signi cant difference in the performance of either analyser, regardless of the route of analysis. Agreement with p...

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Section: Discussionmentioning

confidence: 99%

Comparison of EML 105 and Advantage analysers measuring capillary versus venous whole blood glucose in neonates

McNamara

Sharief

2001

Acta Paediatrica

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“…Recent studies, however, question whether they are sufficiently accurate and reliable for use in critically ill patients (8, 9). According to ADA guidelines (10, 11), error rates in glucose measurement should not exceed 5%, but actual rates greater than 25% have been reported (9, 12, 13). Given the narrow glucose target of 80-110 mg/dL associated with IIT, this degree of measurement error can have a significant clinical impact.…”

Section: Introductionmentioning

confidence: 99%

“…Reported causes of poor glucometer performance include abnormal hematocrit, low oxygen tension, acetaminophen, uric acid, ascorbic acid, maltose, galactose, xylose, lactose, operator inexperience, age of strips, heat, and humidity. Anemia results in error because the estimated volume of plasma equivalent used to calculate glucose concentrations are based on expected plasma displacement associated with normal erythrocyte content (12, 14). In anemic samples the degree of displacement is overestimated, the plasma volume is underestimated, and the reported glucose concentration is thus artificially high.…”

Section: Introductionmentioning

confidence: 99%

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Anemia causes hypoglycemia in intensive care unit patients due to error in single-channel glucometers: Methods of reducing patient risk*

Pidcoke

Wade

Mann

et al. 2010

Critical Care Medicine

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OBJECTIVE Intensive insulin therapy (IIT) in the critically ill reduces mortality but carries the risk of increased hypoglycemia. Point-of-care (POC) blood glucose analysis is standard; however anemia causes falsely high values and potentially masks hypoglycemia. Permissive anemia is routinely practiced in most intensive care units (ICUs). We hypothesized that POC glucometer error due to anemia is prevalent, can be mathematically corrected, and correction uncovers occult hypoglycemia during IIT. DESIGN The study has both retrospective and prospective phases. We reviewed data to verify the presence of systematic error, determine the source of error, and establish the prevalence of anemia. We confirmed our findings by reproducing the error in an in-vitro model. Prospective data was used to develop a correction formula validated by the Monte Carlo method. Correction was implemented in a burn ICU and results evaluated after nine months. SETTING Burn and trauma ICUs at a single research institution. PATIENTS/SUBJECTS Samples for in-vitro studies were taken from healthy volunteers. Samples for formula development were from critically ill patients on IIT. INTERVENTIONS Insulin doses were calculated based on predicted serum glucose values from corrected POC glucometer measurements. MEASUREMENTS Time-matched POC glucose, laboratory glucose, and hematocrit values. MAIN RESULTS We previously found that anemia (HCT<34%) produces systematic error in glucometer measurements. The error was correctible with a mathematical formula developed and validated using prospectively collected data. Error of uncorrected POC glucose ranged from 19% to 29% (p<0.001), improving to ≤5% after mathematical correction of prospective data. Comparison of data pairs before and after correction formula implementation demonstrated a 78% decrease in the incidence of hypoglycemia in critically ill and anemic patients treated with insulin and tight glucose control (p<0.001). CONCLUSIONS A mathematical formula that corrects erroneous POC glucose values due to anemia in ICU patients reduces the incidence of hypoglycemia during IIT.

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“…The results obtained from such meters are affected by multiple factors and accuracy is lost at very high and very low blood glucose concentrations. Severe dehydration, hypotension and high haematocrit (>55%) may cause an underestimation of blood glucose concentration 1,2 . High estimations of blood glucose may be caused by lipaemic blood, low haematocrit (<25%), sugar on the skin at the venesection point and chemicals in the blood that are measured by the meter 3 .…”

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confidence: 99%

Letters to the Editor

Hyde

Betts

2006

J Paediatrics Child Health

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In this case study, 36 h of ceftriaxone therapy the 9-year-old girl complained biliary colic with ultrasonography-proven biliary precipitates. We concluded that ceftriaxone-associated biliary pseudolithiasis can be observed within 2 days of starting ceftriaxone therapy. Dear Editor, References GALACTOSAEMIA PRESENTING AS BEDSIDE HYPERGLYCAEMIAWe would like to highlight a clinically significant but little known limitation of bedside glucometers. A male baby was presented to us at 5 weeks of age with failure to thrive. He had initially breastfed but changed to bottle formula feeds rapidly. He had an enlarged liver span on percussion. Bedside blood glucose testing with the accu-chek advantage II meter showed a concentration of 17.9 mmol/L. Urine dipstix was negative for glucose and ketones. A venous blood gas showed a pH of 7.37, bicarbonate 20.1 nmol/L and base excess −4 mEq/L. Laboratory measurement of blood glucose gave a concentration of 3 mmol/L. Urine-reducing substances were strongly positive, with urine glucose remaining negative. A provisional diagnosis of galactosaemia was made and a subsequent galactose-1-phosphate uridyl transferase level showed no enzyme activity, confirming the diagnosis. The baby was established on a soya-based formula and has begun to thrive.Bedside glucose testing meters have made possible immediate recognition of hypo-and hyperglycaemic states. The results obtained from such meters are affected by multiple factors and accuracy is lost at very high and very low blood glucose concentrations. Severe dehydration, hypotension and high haematocrit (>55%) may cause an underestimation of blood glucose concentration.

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The effect of the haematocrit value on the determination of glucose levels by reagent‐strip methods

Cited by 33 publications

References 5 publications

Comparison of EML 105 and Advantage analysers measuring capillary versus venous whole blood glucose in neonates

Comparison of EML 105 and Advantage analysers measuring capillary versus venous whole blood glucose in neonates

Anemia causes hypoglycemia in intensive care unit patients due to error in single-channel glucometers: Methods of reducing patient risk*

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