Portable blood gas and electrolyte analyzer evaluated in a multiinstitutional study

A recently introduced blood gas/electrolyte analyzer (SenDx 100((R)), renamed ABL70) intended for point-of-care, near-patient, or stat laboratory use was evaluated simultaneously in four different institutions and compared with three different laboratory bench analyzers with respect to imprecision, inaccuracy (assessed by tonometry), and patient-sample analyses. The analyzer is equipped with a sensor cassette and a reagent cartridge for 50, 100, or 200 analyses and 100 or more traditional quality-control measurements. One analysis requires 170 microL of whole blood and takes <90 s. Statistically, the instrument performed somewhat better (lower CVs) for PO2 and potassium and somewhat worse for pH, PCO2, and ionized calcium than the respective comparison analyzers. However, the overall performance (in terms of CV and accuracy) was satisfactory in terms of clinical (e.g., CLIA '88) goals in all institutions. The mean difference and the CV of that difference in some 400 patient-sample comparisons were as follows: 0.010 (+/- 0.002%) for pH, -0.65 mmHg (+/- 4%) for PCO2, -0.49 mmHg (+/- 6%) for Po2, 0.44 mmol/L (+/- 1.2%) for sodium, -0.013 mmol/L (+/- 2.9%) for potassium, -0.016 mmol/L (+/- 2.6%) for ionized calcium, and -0.016 L/L (+/- 7. 1%) for the hematocrit. Its acceptable analytical performance and ease of operation make the SenDx 100 suitable for the analysis of blood gases and electrolytes

Recommendation for measuring and reporting chloride by ISEs in undiluted serum, plasma or blood.

The proposed recommendation for measuring and reporting chloride in undiluted plasma or blood by ion-selective electrodes (ISEs) will provide results that are identical to chloride concentrations measured by coulometry for standardized normal plasma or blood samples. It is applicable to all current ISEs dedicated to chloride measurement in undiluted samples that meet the requirements. However, in samples with reduced water concentration, results by coulometry are lower than by ion-selective electrode due to volume displacement. The quantity measured by this standardized ISE procedure is called the ionized chloride concentration. It may be clinically more relevant than the chloride concentration as determined by coulometry, photometry or by ISE after dilution of the sample