Clinical chemistry
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Multicenter Study
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. ⋯ 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.
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Multicenter Study Comparative Study
Cardiac troponin T and cardiac troponin I: relative values in short-term risk stratification of patients with acute coronary syndromes. GUSTO-IIa Investigators.
We compared cardiac troponins T (cTnT) and I (cTnI) collected within 3.5 h of ischemic symptoms for predicting clinical outcomes in 770 patients. cTnT (cutoff > 0.1 microgram/L) and cTnI (cutoff > 1.5 micrograms/L) were concordant (both positive or negative) in 90.4% of patients. Among discordant results, 66 were cTnT positive and cTnI negative vs 8 who showed the reverse (P < 0.001). ⋯ The area of the ROC curve for predicting 30-day mortality was significantly larger (Z = 2.08; P = 0.0375) for cTnT, at 0.68 [95% confidence interval (CI) 0.60-0.75], compared with cTnI, at 0.64 (95% CI 0.56-0.72). When cTnI and the electrocardiogram (ECG) were put in a logistic multiple regression model, cTnT added significant information (chi 2 = 8.03, P = 0.045); however, cTnI did not add to a model containing cTnT and the ECG (chi 2 = 0.84, P = 0.657). cTnT provided more information than cTnI for predicting 30-day mortality early after presentation with acute coronary syndromes.