Pneumatic tube transport of blood-stained cerebrospinal fluid specimens has no clinically relevant effect on rates of haemolysis compared to manual transport

Abstract

Pneumatic tube transport of pathology specimens from the emergency department to the laboratory for analysis is a widely used practice. When compared to manual specimen transport, it results in savings in both time and labour. Sampling of cerebrospinal fluid still forms part of the workup of patients with suspected subarachnoid haemorrhage. There are claims in the literature that transport of cerebrospinal fluid samples by pneumatic tube results in excess haemolysis, which interferes with cerebrospinal fluid analysis for the presence of bilirubin. The aim of our study was to ascertain whether pneumatic tube transport of blood-stained cerebrospinal fluid to the laboratory, results in clinically significantly higher levels of haemolysis compared with manual transport of the same specimens. Stored cerebrospinal fluid was spiked with varying amounts of red blood cells creating 72 specimens of varying red cell concentration. Half of these specimens were transported to the laboratory manually while the other half were sent by pneumatic tube transport. The rates of haemolysis were compared between the pneumatic tube and manual transport samples. There was no clinically significant difference in the rates of haemolysis between the samples transported to the laboratory by pneumatic tube compared with those moved manually. Pneumatic tube transport of cerebrospinal fluid to the laboratory is not associated with clinically significantly higher rates of haemolysis when compared to manual transport.