Working with a local UK NHS Trust, DJB Labcare has taken part in trials to determine whether any benefit accrues from the centrifugation of patient gel samples in the GP surgery
Samples for electrolyte measurement will, if left in contact with red cells for a prolonged period, yield erroneous potassium results.
GP (general practitioner) surgeries usually have fixed pick up times for transporting specimens to the laboratories.
This leaves them with a choice between limiting phlebotomy sessions to coincide with the transport and asking patients to return to be bled the following day or accepting that samples bled after the transport will not yield a viable potassium result.
The results gathered from the recent UK trials have shown a decrease in anomalous levels of potassium while using gel tubes in the Labofuge 300.
The trial was carried out on two different sites, and what follows is an extract of the trial findings.
Site 1, a moderately busy rural practice, bled all through the day regardless of transport timing and consequently lost 10% of potassium results due to samples being left unspun overnight.
The decrease in 'on cells' samples from 10% to zero was predictable but not as interesting as the decrease in the number of potassium results greater than 5.0mmol/l.
The reduction in potassium results greater than 5.0mmol/l underlines what most labs already recognise in that delays in transportation of un-centrifuged samples can cause unpredictable in vitro changes.
The practice was unanimously skeptical pre trial about the value of centrifugation - but at a post trial meeting, one of the GPs volunteered to demonstrate the centrifuge and its simplicity.
He also emphasised that the whole practice had a new found confidence in all of the potassium results received from the lab.
Site 2 is a large city practice whose staff were very careful about taking basic biochemistry samples time enough to catch the transport.
They did not perform any phlebotomy in the afternoons and community nurse and doctors' round were scheduled around those patients requiring blood tests.
As expected there was very little change in the percentages of useful potassium results but an entirely new work pattern evolved during the trial.
The practice now has phlebotomy services all day and the only patients recalled to be bled in the morning are those requiring fasting tests.
It has also changed the way in which both the community nurses and doctors' home visits are scheduled.
The results demonstrated that the use of a Labofuge 300 in a GP practice could decrease anomalous potassium results, assist in better utilisation of phlebotomy resources, reduce the need to recall patients for non fasting phlebotomy, and give clinical staffs more confidence in the potassium results they receive back from the laboratory.
Manufacturers of gel tubes recommend the use of swing-out rotors in preference to fixed angle rotors, which tend to elongate the gel layer, predisposing to incomplete separation of serum and cells and increased risk of in vitro contamination.
A secure gel barrier means that samples can be stored for longer before testing without deterioration of analytes.
The Labofuge 300 will fit on a worktop, is very simple to use and maintain and can centrifuge between one and eight samples per cycle.
It has a timing device which automatically stops centrifugation after the preset interval.
It provides not only flexibility, but uniform accuracy of results across the board due to the reduction of in vitro contamination.
The Heraeus Labofuge 300 centrifuge is currently available with a 20% discount.
