Pneumatic tube-transported blood samples in lithium heparinate gel separator tubes may be more susceptible to haemolysis than blood samples in serum tubes

Abstract

Pneumatic tube systems are widely used in hospitals. Advantages are high speed and rapid availability of the samples. However, the transportation by pneumatic tube promotes haemolysis. Haemolysis interferes with many spectrophotometric assays and is a common problem in clinical laboratories. The haemolysis index (HI) as a semi-quantitative representation of the level of haemolysis was compared in unpaired tube-transported and hand-delivered routine lithium heparinate plasma samples (n = 1368 and n = 837, respectively). Additionally, the HI distribution was measured in lithium heparinate plasma samples with a HI above the threshold value of 20 and in paired serum samples after transportation by pneumatic tube system. HI values above 20 can interfere with the selected assays: Creatine kinase (CK), creatine kinase-MB (CK-MB) and alanine aminotransferase (ALT) activities. These parameters were determined to demonstrate how haemolysis affects the results. 17.5% of the tube-transported plasma samples and 2.6% of the hand-delivered plasma samples had a HI above 20. The median HI in pneumatic tube-transported lithium heparinate plasma was 85 and 33 in the paired serum samples. The median HI difference between paired plasma and serum was 46. Blood samples in lithium heparinate tubes may be substantially more susceptible to haemolysis by pneumatic tube transportation than serum tube samples. Although our results cannot be universally applied to laboratories with different pneumatic tube systems, it is recommended that each laboratory evaluate carefully the degree of haemolysis after the transportation by the own pneumatic tube system and in terms of the sample type.

Rapid serum clot tubes reduce haemolysis due to pneumatic tube transport

“…This study is the first to demonstrate that RST tubes can significantly reduce PTS-induced haemolysis, resulting in fewer haemolysis-related sample rejections. Our findings are consistent with previous studies who found PTS transport of clotted blood maintains sample integrity better than anticoagulated blood 2–4. Our study sheds additional light on the mechanism of protection offered by clotted blood through the use of RST that ensures the sample is completely clotted before transport.…”

“…Susceptibility to PTS-induced haemolysis varies among blood collection tube type, suggesting another mitigation strategy laboratories can easily implement. A higher rate of PTS-induced haemolysis has been observed in lithium heparin tubes relative to serum tubes, leading to the speculation that cells within a clot are protected from the mechanical stresses of PTS transport 2 3. Additionally, air bubble formation during PTS transport of anticoagulated blood has been shown to contribute to haemolysis 4.…”

Stability of Routine Biochemical Analytes in Whole Blood and Plasma From Lithium Heparin Gel Tubes During 6‐hr Storage

“…Considering the RCV , the decrease in PHOS concentration after 3–4 hr of whole blood storage and the slight decreases observed for LDH and K concentrations can be considered devoid of clinical significance up to 6 hr (RCV = 23.1%, 24.4%, and 13.4%, respectively; Supporting Information Table B), as previously reported . Finally, it must be noted that the design of our substudy on whole blood did not take into account the influence of the pneumatic tube system, which potentially increases the hemolysis degree, thus impacting the concentration of sensitive analytes .…”

Use of clinical data and acceleration profiles to validate pneumatic transportation systems

“…Several papers describe how PTS may increase the risk of in vitro hemolysis [2,[8][9][10]. Clinical chemistry analyses are most often discussed in this context; however, blood gas, hematology and coagulation analyses have also been subject to evaluation when assessing the effects of PTS on specimen integrity [4,11,12].…”