ANALYTICAL EVALUATION OF I-STAT PORTABLE CLINICAL ANALYZER AND USE BYNONLABORATORY HEALTH-CARE PROFESSIONALS

We evaluated the performance of the i-STAT Portable Clinical Analyzer, a hand-held instrument that, with its current cartridge, analyzes for electrolytes, urea nitrogen, glucose, and hematocrit in approximately 60 muL of whole blood in approximately 90 s. Accuracy, imprecision, a nd linearity studies were performed with aqueous controls and standard s and by split-sample analysis. Intrarun imprecision (CV) ranged from 0.34% to 3.97%. Total imprecision over a 2-month period ranged from 0. 42% to 4.83%, with urea nitrogen and glucose analyses generating the h igher values. Patients' results from the Portable Clinical Analyzer co rrelated well with those obtained for whole blood or plasma by the Nov a Stat Profile 5, the Beckman Synchron CX3, or the Technicon Hl Hemato logy Analyzer, with S(y\x) values <0.2 mmol/L for potassium; <1.5 mmol /L for sodium, glucose, and urea nitrogen; <2.4 mmol/L for chloride; a nd <2.4% for hematocrit. We also ascertained imprecision and accuracy of the system placed in a cardiothoracic intensive-care unit and opera ted by nurses. There were no significant differences in either the imp recision or accuracy of the system in this setting. We conclude that o perator technique is not a factor in the analytical performance of the system and that it can be used by nonlaboratorians with a high degree of confidence that reliable results will be obtained.