Effect of pneumatic tube transport on T lymphocyte subsets analysis

Pneumatic tube system (PTS) for transportation of blood specimens may present with advantages for hospital organization as it provides faster tube transfer from medical wards to routine labs. These characteristics are expected to result in faster sample processing and decreased turnaround time, therefore benefiting the patient particularly in emergency units. However, PTS could affect sample quality and therefore laboratory results. Within the context of routine lab certification, effects of PTS on routine cellular immunology analyses, especially on determination of T lymphocyte subpopulations, need to be evaluated.

Paired EDTA blood samples were collected from 30 healthy donors. For each pair, one sample was hand-delivered by a courier while the other was transported through a PTS of 2.4 km long (1.6 miles) with two 90-degree turns and one-U turn generating a speed of 5 m/s with a maximal acceleration of 2 g-force. The percentages of CD3+ cells, CD4+ and CD8+ T-cells and their absolute counts were assessed by flow cytometry.

For every parameter, results measured by flow cytometry were not significantly different after transport by PTS or hand-delivery. Results comparison revealed an excellent linear correlation between both delivery methods (R ranged from 0.969 to 0.982; P < 0.01). Bland-Altman plots also showed good agreement, indicating that results were not influenced by the transport method.

Our results suggest that, pending validation using clinical samples, PTS does not present with pre-analytical drawbacks and is thus a reliable system for blood samples transportation when performing T cell subset phenotyping.