Introduction
In Denmark with a population of 5.5 million, approximately
3 million blood samples are drawn each year
in General Practice (GP) and sent to hospital laboratories
for analyses.
The transport logistics are different for various
counties in Denmark. Samples (whole blood or plasma)
are transported by mail, by ‘‘hospital car’’, taxi,
coach or private transport. In at least one county all
these possibilities are used. Pre-analytical factors also
vary: the samples are drawn in tubes with or without
separation gel, sent with or without centrifugation, or
with centrifugation followed by plasma separation (1,
2). Some hospital laboratories keep the samples at a
constant temperature of 21"18C (1). Also, different
brands of tubes are used.
The pre-analytical conditions have a decisive
impact on the final result and may lead to diagnostic
mistakes. Sinclair et al. (3) describe seasonal pseudohyperkalaemia
during transport of samples. A recently
published paper (4) deals with spurious hyperkalaemia
caused by storage of the sample and transport
conditions.
Centrifugation of blood samples before transport is
time consuming and expensive. Furthermore, transfer
of plasma to another tube increases both the risk of
sample mismatch and infection. Therefore, it is preferable
to transport whole blood. As both the economical
and quality consequences of pre-analytical
solutions are considerable, our aim was to investigate
which combination of storage time, storage temperature
and transport method would allow the use of
primary tubes with whole blood or ‘‘on gel’’ after centrifugation.
All existing procedures in two counties
were investigated.
The focus was on combinations of transport conditions
as such and not on a single factor.