Interchangeability of Electrolyte and Metabolite Testing on Blood Gas and Core Laboratory Analyzers.

BACKGROUND: Using blood gas (BG) analyzers as backups for core laboratory analyzers has the potential to greatly reduce turnaround times and costs. METHODS: One venous blood gas syringe, one plasma separator tube (PST), and one serum separator tube (SST) were drawn from 42 healthy individuals. All samples were run on the GEM4000 BG analyzer whereas the PST and SST samples were also run on the Roche Modular chemistry analyzer. Blood electrolyte and metabolite parameters were compared for paired measurements, and their differences were assessed for statistical and clinical significance. RESULTS: Whole blood on GEM4000 and plasma/serum on Roche Modular produced incomparable results for Na+ in plasma and serum (2.5 percentile difference, GEM4000 - Modular: -4.975 and -4.95 mmol/L, respectively) and K+ in serum (2.5 percentile difference, GEM4000 - Modular: -0.7975 mmol/L). When comparing whole blood to plasma/serum samples, all from the GEM4000, incomparable parameters were also found for Cl- in plasma and serum (97.5 percentile difference, plasma or serum - whole blood: 6 and 5 mmol/L, respectively), and K+ in serum (97.5 percentile difference, serum - whole blood: 0.7 mmol/L). None of the parameter differences when comparing plasma/serum results on the GEM4000 to those on the Roche Modular were found to be clinically significant. CONCLUSIONS: The off-label use of plasma/serum on a BG analyzer produced electrolyte and metabolite measurements that were more interchangeable with standard core laboratory analyzer results than with its designated whole blood samples. The interchangeability of results, therefore, seems to be affected more by different sample types than by different measurement methods.

Comparison of Becton Dickinson Vacutainer rapid serum tube with the serum separator tube for routine chemistry and immunoassay tests.

AIMS: To shorten the clotting time and resolve the delayed clotting or no clotting on specimens from patients on anticoagulant therapy, Becton Dickinson (BD) recently developed the Vacutainer rapid serum tube (RST). The aim of this study was to systematically compare the new RST tube with the widely used serum separator tube (SST) for routine chemistry and immunoassay tests on 3 common analyser platforms. METHODS: Blood from 45 people (24 women and 21 men, age 21-77 years) was collected using the SST and RST tubes in sequence. Sera from both tubes were separated and analysed simultaneously for 54, 50, and 10 chemistry and/or immunoassay tests on the Roche Modular, Abbott Architect, and Siemens Centaur analysers, respectively. RESULTS: The results from the RST tube were comparable with those from the SST tube on most analytes. Although the results for a few analytes showed statistically significant differences between the two tubes (p<0.05), the differences had no clinical significance for most assays. Only for parathyroid hormone on the Abbott Architect, the RST tube demonstrated clinical significant bias versus the SST tube (-15.3%, p<0.01). CONCLUSIONS: The RST tube provides acceptable performance for routine chemistry and immunoassay tests.