One of the main advantages of POCT over laboratory testing is the relative immediacy of results. This may enable prompt treatment, shortened patient waiting time and a reduced number of out-patient appointments and clinic visits for the patient.

Many POCT devices require minimal specimen preparation or collection (in some cases using a finger prick of blood). The machine is in the near-patient setting, thus reducing the delays associated with the transport of specimens and reports.

The recent increase in POCT has been due partly to technological changes in the design of analysers. With the advent of microchips, computerization and miniaturization, it has become easier to bring analysis nearer to the patient and for it to be performed by personnel with minimal training or by the patients themselves. Some of the modern POCT devices incorporate biosensors, electrodes and dry- and solid-phase chemistry reagents. These allow for small sample and reagent volumes, quick assay reaction times, ease of use and disposal of used reagents, more than one analyte to be measured simultaneously and probably less technical skill.

Transcutaneous biosensors allow continuous measurements to be made through the patient’s skin without the need for blood collection. Near-infrared spectroscopy may allow continuous monitoring of more than one analyte as well as in vivo glucose monitoring with implantable sensors in diabetic patients.

In choosing a POCT analyser system, remember that duplication may occur within the hospital at separate sites. Different analysers on the same site may result in the use of different reference ranges and thus difficulties in comparing patient results. Many of the new POCT analysers are relatively easy to maintain, but maintenance may need to be carried out by non-laboratory staff out of the laboratory setting. It is also likely that results will need to be interpreted and troubleshooting performed by non-laboratory personnel.

The reduction in turnaround time may result in a reduction in total costs if patient episodes are shorter and transport costs are reduced, for example courier costs. However, on a direct charge basis, including capital costs, POCT may be more expensive than central laboratory testing. This can be due in part to duplication of tests overall and to economies of scale. The costs of reagents and machines, quality control materials, maintenance, storage of report forms and results and training may all need to be taken into consideration when embarking on POCT. Labour costs are more difficult to assess in POCT, but may incorporate nursing staff; however, set against this are possible savings of on-call or out-of-hours costs for laboratory staff.

Depending on the structure and organization of the POCT setting, the overall costs could be less when the merits of rapid therapeutic responses and shorter hospital stays are taken into consideration (Box 30.1). It is essential that there is proper user training and also maintenance of a complete audit trail for patient results.