Performance evaluation of low-volume blood collection tubes for coagulation tests

Frequent phlebotomy for laboratory testing is a major cause of iatrogenic blood loss, particularly in critical care settings. Conventional large-volume blood collection tubes often collect blood far in excess of analyzer requirements. This study evaluated the analytical performance of novel 1 mL vacuum blood collection tubes compared to conventional 3 mL tubes for coagulation testing, assessing their potential to reduce diagnostic blood loss without compromising test quality.

Following the established guidelines (CLSI EP07 and WST 224-2018), the performance of 1 mL microsample tubes was systematically compared with conventional 3 mL tubes. The evaluation indicators covered aspiration volume accuracy, result comparability of six coagulation parameters, and anti-interference capability against hemolysis, icterus, and lipemia (HIL). The six detected coagulation parameters included activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), fibrinogen (FIB), D-dimer, and antithrombin III (ATIII). Passing-Bablok regression analysis and Bland-Altman analysis were performed to assess the consistency and bias of detection results. All tests were implemented on a CX9000 automated coagulation analyzer.

The aspiration volume deviation (Rb) for the microsample tube (4.0%) was comparable to the conventional tube (4.9%), both within the acceptable ± 10% tolerance. Passing-Bablok regression demonstrated high concordance between 1 mL microtubes and conventional tubes across all six coagulation parameters (n = 46-71), with slopes ranging from 0.931 to 1.051 and intercepts from - 0.018 to 2.555; all P-values for deviation from linearity were non-significant. Bland-Altman analysis confirmed that all evaluated coagulation parameters met the predefined clinical consistency criteria.

The 1 mL vacuum coagulation tube demonstrated equivalent analytical performance to conventional 3 mL tubes across 6 routine coagulation parameters, including aspiration accuracy, result comparability, and interference resistance. Its implementation can significantly reduce blood draw volumes by over 50%, offering a reliable and blood-conserving solution for coagulation testing, especially beneficial for critical care, pediatric, and other vulnerable patients.