Retrospective analysis of intra-patient laboratory variation demonstrates that the BD Vacutainer? BarricorTM blood collection tube reduces troponin variation

Objective: The BD Vacutainer (R) BarricorTM plasma blood collection tube uses a mechanical separator during centrifugation to separate plasma from the cellular elements of blood. Compared to use of plasma separator tubes (PSTTM) with gel, BarricorTM produces a cleaner sample with less residual cellular content. We sought to determine if BarricorTM reduces pre-analytical error compared to PSTTM.Design & Methods: We used a model previously published that utilizes serial differences between intra-patient measurements transformed into a Taylor series of variation vs time with the y-intercept equal to the sum of short-term analytic variation, preanalytic variation and biologic variation. The intra-patient variation of chlo-ride, sodium, potassium, and troponin-T (hs-TnT) obtained from the Emergency Department of a large tertiary care center sampled with PSTTM (May 2015-April 2018, n = 59,762 specimens) or BarricorTM (May 2018-May 2021, n = 61,512 specimens) was evaluated. All specimens were analyzed on either Roche Modular or Cobas (R) instruments. For each analyte, pairs of intra-patient results were tabulated and separated by 1 h in-tervals. The average between-pair variations were then regressed against time. We also determined the number of intra-patient outliers using the reference change value for each analyte.Results: The BarricorTM hs-TnT y-intercept (-0.0132) was significantly lower than the PSTTM intercept (0.9109; p = 0.022). This was also true for chloride (y-intercept = 1.0067 in BarricorTM and 1.3431 in PSTTM, p = 0.037). The percentage of hs-TnT outliers was significantly lower in BarricorTM (8.32 %) vs PSTTM (12.2 %; p < 0.001).Conclusion: The analytical and biological variations are assumed to be steady over the study periods; we ascribe the difference in the y-intercept to the preanalytical effect of the BarricorTM tube reducing platelets and other cellular debris.

Automated summary

This study demonstrates that the use of BD Vacutainer BarricorTM plasma blood collection tube reduces pre-analytical errors compared to the use of PSTTM tubes.