Comparison of pneumatic tube system with manual transport for routine chemistry, hematology, coagulation and blood gas tests

Background: The pneumatic tube system (PTS) is commonly used in modern clinical laboratories to provide quick specimen delivery. However, its impact on sample integrity and laboratory testing results are still debatable. In addition, each PTS installation and configuration is unique to its institution. We sought to validate our Swiss-log PTS by comparing routine chemistry, hematology, coagulation and blood gas test results and sample integrity indices between duplicate samples transported either manually or by PTS. Methods: Duplicate samples were delivered to the core laboratory manually by human courier or via the Swiss-log PTS. Head-to-head comparisons of 48 routine chemistry, hematology, coagulation and blood gas laboratory tests, and three sample integrity indices were conducted on 41 healthy volunteers and 61 adult patients. Results: The PTS showed no impact on sample hemolysis, lipemia, or icterus indices (all p<0.05). Although alkaline phosphatase, total bilirubin and hemoglobin reached statistical significance (p=0.009, 0.027 and 0.012, respectively), all had very low average bias which ranged from 0.01% to 2%. Potassium, total hemoglobin and percent deoxyhemoglobin were statistically significant for the neonatal capillary tube study (p=0.011, 0.033 and 0.041, respectively) but no biases greater than +/- 4% were identified for these parameters. All observed differences of these 48 laboratory tests were not clinically significant. Conclusions: The modern PTS investigated in this study is acceptable for reliable sample delivery for routine chemistry, hematology, coagulation and blood gas (in syringe and capillary tube) laboratory tests.