The Science Journal of the American Association for Respiratory Care

2001 OPEN FORUM Abstracts

ANALYTICAL PERFORMANCEOF GLUCOSE AND LACTATE SENSORS IN THE GEM PREMIER 3000 ANALYZER.

Sohrab Mansouri,Clarke Xu, Melanie Shin. Instrumentation Laboratory, 101 Hartwell Ave, Lexington,MA 02421.

Background:The GEM line of blood analyzers are unique in that they are using a disposablecartridge containing all elements necessary for sample analysis including miniaturizedsensors, reagents, fluidic system and waste container. The latest cartridgefor the GEM Premier 3000 analyzer has capability to measure pH, PCO2, PO2, sodium,potassium, calcium, glucose, lactate, and hematocrit in 150 mL sample volume.The cartridge can analyze up to 450 samples and can be operated continuouslyfor up to three weeks. In this report we present the analytical performancecharacteristics of the glucose and lactate sensors.

Method: Theglucose and lactate sensors are integrated in a plastic sensor card alongsidethe other gas, electrolyte and hematocrit sensors. The glucose and lactate measurementsare based on amperometric electrochemical detection with three electrode configurationsconsisting of a platinum working, reference and counter electrodes. The workingelectrode is fabricated of a composite membrane containing inner, enzyme, andouter layers. The enzyme later has glucose oxidase for glucose and lactate oxidasefor lactate detection. The inner and outer membranes are optimized to minimizethe effects of commonly existing interfering compounds and the oxygen levelin whole blood. The analytical performances of the glucose and lactate sensorswere compared against standard laboratory bench analyzers (ABL 605 from Radiometerand Synthesis 1745 from Instrumentation Laboratory). Six levels of glucose andlactate were evaluated using fresh, heparinized whole blood from healthy volunteers.The samples were spiked or diluted and tested in 4 replicates per run. The bloodruns were conducted once per week for three weeks using 7 cartridges from 3different production lots.

Results:The bias results are calculated using pooled GEM results and are compared withthe bench analyzer results. Also shown in the table are within run SD and pooledSD to determine imprecision per level.

GEMMeanBenchMeanAvg.Within Run SDTotalPool SD
Glucose mg/dLLactate mmol/LGlucose mg/dLLactate mmol/LGlucose mg/dLLactate mmol/LGlucose mg/dLLactate mmol/L
30.00.5530.20.571.50.081.60.08
53.11.4153.31.432.10.082.10.09
97.62.4097.82.573.00.063.60.10
1775.161765.316.90.147.50.18
3488.293438.5014.90.2415.30.31
44110.143210.621.100.3021.40.49

Conclusion:Our results show that the overall performance of the glucose and lactate sensorsin GEM Premier 3000 analyzer compares favorably to standard laboratory analyzersand blood precision values are well within clinical limits.

OF-01-232

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