Minimizing high sensitivity troponin T delta variation at low concentration using BD Barricor blood collection tube

OBJECTIVE: Reproducible low troponin concentrations from high-sensitivity troponin (hs-cTn) assays are paramount to accurate risk determination in the accelerated diagnostic pathway. Total variation consists of pre-analytical, analytical and biological components. While analytical and biological variations cannot be readily modifiable, minimizing pre-analytical variation is desirable and potentially attainable. The BD Barricor collection tube has previously been demonstrated to reduce pre-analytical variation in test results. The goal of the study is to determine whether BD Barricor tubes provide more reproducible hs-cTnT results compared to plasma separator tubes (PST) at concentrations ≤ 20 ng/L. METHODS: Paired intra-patient hs-cTnT results collected less than 1 h apart in the emergency department were retrospectively analyzed from nine urban hospitals which primarily use either PST (n = 336 pairs) or Barricor (n = 327 pairs) collection tubes for troponin. Total variation of the replicated measurements was calculated for hs-cTnT ≤ 20 ng/L. The numbers of paired intra-patient samples were grouped based on decisive absolute delta thresholds as indicated by the European Society of Cardiology 0/1 h algorithm; delta < 3 ng/L, 3-4 ng/L, ≥5 ng/L. RESULTS: The total testing variation for hs-cTnT collected in PST is 14.8 % while Barricor is 8.6 % for hs-cTnT ≤ 20 ng/L. The proportion of delta values < 3 ng/L between the intra-patient replicates is 80.4 % (95 % CI: 75.7-84.5 %) in PST compared to 95.4 % (95 % CI: 92.5-97.4 %) in Barricor (p < 0.001). Median time for serial sampling in PST is 41 min (IQR:18-53) and Barricor is 45 min (IQR 23-54). CONCLUSION: The use of Barricor tubes demonstrated reproducible and less variable hs-cTnT replicates at concentration ≤ 20 ng/L when compared to a hospital that does not use Barricor tubes.