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Near-patient testing: is this the future?

Charles Broomhead
MB ChB MRCGP DA DRCOG
GP and GP Trainer
Sutton Coldfield
Honorary Clinical Lecturer
Birmingham Medical School

Near-patient testing (NPT), also sometimes referred to as point-of-care or extralaboratory testing, is not a new concept. Delaney et al described it as any investigation performed in a clinical setting or in a patient's home for which the result is available without reference to a laboratory and perhaps rapidly enough to affect immediate patient management.(1)
In its simplest form it is exemplified by a doctor or nurse testing a urine sample for the presence of glucose, albumin or other abnormal constituents. Originally such testing would have demanded the use of laboratory equipment and chemical reagents, and indeed many early attempts at NPT involved the performance of small-scale laboratory experiments. With the development of new techniques, however, the procedures have become greatly simplified, and many tests have evolved into the use of the now familiar dry test strips. But while the range of tests available has dramatically escalated, so to has their cost.
In principle it seems attractive to be able to give patients the results of their tests immediately. Indeed there are instances, such as the measurement of blood glucose levels in diabetic patients, where such information has transformed the overall management of their condition. Being able to check whether an addict has recently taken drugs such as cocaine or heroin and is complying with his/her detoxification plan can help to control the availability of illicit drugs in the community. The ability to tell the anxious patient in front of you that she is or is not pregnant can bring immediate delight or perhaps allow the arrangement of an earlier termination. Demonstrating that the amount of carbon monoxide in an exsmoker's exhaled breath has fallen within a short while of quitting can be a powerful motivational tool to encourage continuing compliance with medical advice.
If it was possible to use a simple quick and reliable test to distinguish between bacterial and viral infections or to tell whether a urinary tract infection was present, the huge number of antibiotics that are prescribed unnecessarily each year might be dramatically reduced, or at least they might be used more appropriately. This would of course have beneficial effects in reducing the chance of bacterial resistance developing, and might also produce significant cost savings.
In reality, however, the benefits of NPT may not always outweigh the disadvantages. Hilton demonstrated that the initially high expectations of both GPs and their nurses were not sustained when they had the opportunity to expand the range of tests that they provided in their surgeries.(2)
Initially 80% of GPs expected that patient management would change, but only 40% reported that this had actually been the case when they were requestioned after six months. In this study, pressure on nurse time was found to be a significant barrier and was cited as the main drawback to the wider use of NPT. The same study did, however, demonstrate some advantages for patients, such as there being less need for them to contact or return to the surgery to obtain laboratory results.
Another study has shown that patients undergoing NPT have higher levels of satisfaction with the process and are more likely to recall the results of their investigations than when conventional testing techniques are used.(3) This same study suggested that the standard of care was improved when the results of glycaemic control-related NPT were available at the time of the consultation.
As technology advances it has become possible to perform an increasing number of tests within the surgery environment without the need to send samples to a distant laboratory. While there may often be considerable merit in this option, there are a number of other aspects of this practice that must also be considered. Not least of these is the increasing availability of "online" laboratory results. This facility reduces the delay and inconvenience that often characterises the use of a remote testing facility and eliminates some of the immediate benefits of NPT. A further advantage of the electronic transfer of laboratory results is that they can often be sent directly to an individual patient's computer record. This both ensures that the record is complete and obviates the need for manual entry with its inherent danger of transcription errors.
A further major consideration must be whether NPT is cost-effective. Assessment of this will include not only the cost of materials and test strips, but also other the cost of resources such as the doctor or nurse time that is used in the process. There may also be a need to provide and maintain expensive test equipment and facilities. A report produced by the Health Services Research Unit at the University of Warwick showed that, for cholesterol alone, NPT could increase the investigation costs of an average practice by £2,400, even if there was no increase in the number of tests performed.(4)
Quality control must also be of paramount importance, it being axiomatic that the results of NPT are consistently reliable and safe. Murray and Hilton demonstrated that this is an aspect of NPT that appears to receive little consideration.(2,5) This finding obviously gives rise to considerable cause for concern regarding the increasing emphasis that is being placed on the provision of community-based care.
In 1997 the NHS Research and Development Health Technology Assessment Programme commissioned a systematic review of NPT.(6) One of the main conclusions of this report was that there was "little evidence to support the general introduction of NPT into general practice in preference to existing laboratory services", and that this was a subject that required further evaluation. Clearly this is something that must be done before we wholeheartedly embark on replacing what are often highly efficient laboratory tests, albeit at some distance from our patients, with less efficient and reliable yet more expensive tests within our surgeries.
There are obviously situations where NPT is and should remain the "gold standard", but it is by no means clear that all investigations are best dealt with in this way even if we possess the technology to do so.

References

  1. Delaney BC, Hyde CJ, McManus RJ, et al. Systematic review of near patient testing evaluations in primary care. BMJ 1999;319:824-7.
  2. Hilton S, Rink E, Fletcher J, et al. Near patient testing in general practice: attitudes of general practitioners and practice nurses, and quality assurance procedures carried out. Br J Gen Pract 1994;44:577-80.
  3. Grieve R, Beech R, Vincent J, Mazurkiewicz J. Near patient testing in diabetes clinics: appraising the costs and outcomes. Health Technol Assess 1999;3(15):1-74.
  4. Health Services Research Unit, University of Warwick. Near patient testing in general practice. University of Warwick; 1994.
  5. Murray ET, Fitzmaurice DA. An evaluation of quality control activity for near patient testing in primary care. Br J Gen Pract 1998;48:1853-4.
  6. Hobbs FDR, Delaney BC, Fitzmaurice DA, et al. A review of near patient testing in primary care. Health Technol Assess 1997;1(5):i-iv

Resources
The Medical Devices Agency (MDA)
is preparing a "Device Bulletin" on the purchase, management and use of near-patient testing equipment
W:www.medical-devices.gov.uk/mda/mdawebsitev2.nsf/webvwKeyTopics

Institute of Biomedical Science in London
Leaflets about the responsibility for and operation of near-patient testing are available on request
W:www.ibsm.org/00/public/leaflets/index.php3

The Bandolier website has a lot of good quality information about near-patient testing
W:www.jr2.ox.ac.uk