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Changes in blood gas samples produced by a pneumatic tube system
  1. P O Collinson,
  2. C M John,
  3. D C Gaze,
  4. L F Ferrigan,
  5. D G Cramp
  1. Department of Chemical Pathology, Mayday Hospital, London Road, Croydon CR7 7YE, UK
  1. Correspondence to:
 Dr PO Collinson, Department of Clinical Biochemistry, 2nd Floor, Jenner Wing, St George's Hospital, Blackshaw Road, London SW17 0QT, UK;


Aims: To investigate the effect of a pneumatic tube system (PTS) on the results of samples sent for blood gas analysis to a central laboratory.

Methods: Blood gas samples were analysed immediately or sent via the PTS to the laboratory for analysis. In addition, samples sent via the PTS in a pressure sealed container were compared with those sent non-pressure sealed to the laboratory.

Results: Samples sent via the PTS had significant alterations in their pO2 values, which were not seen when samples were carried by hand to the laboratory. There was no effect on pCO2 and pH values. The use of a pressure sealed container abolished the alteration in pO2 values seen.

Conclusions: Samples for blood gas analysis should be transported via a PTS using a pressure sealed container to avoid artefacts in the pO2.

  • pneumatic tube system
  • blood gas analysis
  • pressurised container
  • oxygen pressure
  • CV, coefficient of variation
  • ICU, intensive care unit, IQR, interquartile range
  • NS, not significant
  • POCT, point of care testing
  • PTS, pneumatic tube system
  • TAT, turnaround time

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