Determining the best method for first-line assessment of neonatal blood glucose levels

The accuracy of a glucose-oxidase-based point-of-care glucometer in premature infants

OBJECTIVE

The purpose of this study was to evaluate the accuracy of a novel commercial glucose-oxidase (GO)-based glucometer in measuring glucose concentrations in arterial blood samples collected from premature infants.

PATIENTS AND METHODS

A commercial glucometer, which is a plasma separation GO-based glucometer, was employed to compare the accuracy of the commercial blood glucometer with that of a standard glucose analyser for monitoring blood glucose levels in premature infants. Arterial blood samples were collected and analysed, including samples adjusted for specific glucose (3.6 mmol/L, 8.3 mmol/L and 16.7 mmol/L) and PaO2 levels (range, 40-400 mm Hg).

RESULTS

In total, 159 samples were collected. Bland-Altman analysis showed good correlation between the commercial glucometer and standard glucose analyser. Error-grid analysis revealed that all of the results were within zone A (ie, the clinically accurate estimate zone). The biases between the two systems were low at different PaO2 levels and haematocrits. Finally, the influence of different PaO2 levels was within acceptable ranges.

CONCLUSIONS

The GO-based glucometer evaluated in this study provides accurate results even when measured at high PaO2 and different haematocrits and is suitable for measuring arterial glucose levels in premature infants.

Clinical performance of the new glucometer in the nursery and neonatal intensive care unit

BACKGROUND

  Performance of point-of-care (POC) glucometers in newborns have been unsatisfactory in low glucose concentration range and the effects of different hematocrit levels on glucose measurements have also demonstrated in currently used POC glucometers.

METHODS

  The aim of this study was to evaluate the performance of the new glucometer (Nova-Statstrip(®) ; Nova Biomedical, Waltham, MA, USA) compared to the reference method. Venous blood specimens of neonates were collected and tested by the two glucometers. Standard reference was performed using the hexokinase method within 10 min of blood collection. Hematocrit and total serum bilirubin measurements were performed simultaneously.

RESULTS

  One hundred and fifty-one blood specimens were collected and measured by the reference method with plasma glucose concentrations ranging from 12 to 371 mg/dL. Twenty-one specimens had plasma glucose concentrations <45 mg/dL. At plasma glucose concentrations less than 75 mg/dL, the Statstrip(®) achieved 93% in the tests for discrepancy < 15 mg/dL. At a glucose concentration more than 75 mg/dL, 97% of the Statstrip(®) readings were within 20% of the reference values. The mean difference (±2SD) of the Statstrip(®) was 2.8 (-14.1, 19.7) mg/dL. At a hypoglycemic level (<45 mg/dL), it showed a sensitivity of 95.2%. No significant interference of hematocrit or total serum bilirubin was found on the mean bias of the Statstrip(®) .

CONCLUSION

  The new glucometer (Nova-Statstrip(®) ) could be used for point-of-care blood glucose measurement in neonates as it showed a narrow margin of error and had no hematocrit or bilirubin interference.

Evaluation of the Glucometer Elite XL device for screening for neonatal hypoglycaemia

To prevent persistent neurodevelopment and physical growth deficits in neonatal care, it is mandatory to determine blood glucose levels as quickly and precisely as possible, preferably using micro-methods. However, most commercially available instruments have not been validated and approved for this purpose. The aim of this study was to validate the Glucometer Elite XL, a newly developed device for point-of-care testing (POCT). In samples from 869 newborn infants, glucose levels were simultaneously measured by the Glucometer Elite XL in whole blood and by an accepted clinical laboratory method in haemolysed blood using the ECA 2000 device. An acceptable method agreement was found between the POCT and the ECA 2000 method (mean difference 0.013 mmol/l, SD 0.69). As determined by regression analysis (Passing-Bablok), the slope was 1.086 with a y-intercept of -0.4 mmol/l ( r =0.959, P <0.05). The differences between measurement pairs of both assays versus the haematocrit were negligible. With a cut-off for hypoglycaemia at 2.6 mmol/l glucose in haemolysed blood, the sensitivity of the POCT device was 0.63 and specificity was 0.98. Raising the cut-off of the Glucometer Elite XL to 3.2 mmol/l, the sensitivity and specificity incremented to 1.0 and 0.89, respectively.

CONCLUSION

The Glucometer Elite XL instrument can be recommended for point-of-care blood glucose measurement in newborn infants if its character as a screening method is taken into account. To compensate deviating results, we advise to shift its cut-off for hypoglycaemia recognition to a safe threshold of 3.2 mmol/l. However, hypoglycaemia has to be confirmed by a valid glucose measurement in the clinical laboratory.

Selecting an accurate point-of-care testing system: clinical and technical issues and implications in neonatal blood glucose monitoring

ISSUES AND PURPOSE

Rapid identification and treatment of glucose abnormalities is crucial in the prevention of potentially devastating neurological injury in neonates. Choice of a point-of-care glucose testing system must consider accuracy, clinical advantages, and data management capabilities.

CONCLUSIONS

The benefits and limitations of point-of-care testing must be weighed against the time delay of central laboratory testing.

PRACTICE IMPLICATIONS

Considerations in selecting a point-of-care blood glucose monitoring system include accuracy, precision, versatility, and the potential for cross infection and blood loss. When a system is selected, studies must be done to identify potential sources of error and confirm the utility and accuracy of the system in the identified population.