Pneumatic tube system induced haemolysis: assessing sample type susceptibility to haemolysis

The pneumatic tube system (PTS) has been implicated in inducing haemolysis. It is not known whether certain sample types are more susceptible to haemolysis than others. We assessed the level of haemolysis in commonly used sample types in the clinical biochemistry department when transported through the PTS.Blood was collected in pairs for different sample types and sent to the laboratory via the pneumatic tube or delivered by a porter. Haemolysis indices were measured spectrophotometrically and compared for each pair of sample type.Our results suggest that plain serum samples are more susceptible to haemolysis than the other sample types when sent through our PTS (P <0.0001). Compared with serum with gel samples, plain serum samples are more prone to haemolysis (P <0.001). This suggests that gel may confer some protection against haemolysis.Different hospitals will have varying system configurations and use different sample types. We recommend that each hospital investigate their own system to assess whether haemolysis is a recurring problem in any of the sample types transported.