Near patient testing in primary care

Offers better patient management but needs proper evaluation and quality control

Near patient or point of care testing has been documented at least since Thomas Willis (1621-1675) wrote of tasting urine to test for glycosuria. Today, every doctor uses dry reagent laboratory sticks for simple urine analysis or blood sugar estimation, both in clinics or offices and in patients' homes. In the United States near patient testing now comprises 20% of all testing,1 and the past decade has seen increasing interest in the use of dedicated single test devices or desk top chemistry analysers among doctors in Europe, particularly in Britain,2 3 the Netherlands,4 and Scandinavia.5 In all countries it is in primary care that the true potential for near patient testing will be realised.

Near patient testing could improve the accuracy of clinical decision making and the reliability of monitoring chronic diseases, assisted if necessary by expert decision support.6 Primary care physicians are under multiple pressures to extend and improve their performance in these critical areas. These pressures include patients' increasing intolerance of late diagnosis, growing requirements to ration access to specialist care, sicker patients in the community because of earlier discharge from hospital, and the ever greater demands upon general practitioners to manage the surveillance of chronic diseases. However, if primary care physicians are to manage more patients more reliably and at least as safely, they will need accurate and efficient tools to assist their decisions (in addition to extra facilities and staff). Near patient testing will contribute to the wider use of appropriate investigation in primary care.

As with new drugs, the efficacy and safety of new diagnostic technologies must be demonstrated both in laboratory and practice settings, including clinical and economic comparisons of different technologies. One major problem is deciding who should fund such research. The most likely sources of funding in Britain will be the NHS central research and development health technology programme (which recently commissioned a systematic review on this subject) and the Medical Research Council through the Realising our Potential Awards (RoPAs) scheme.

Facilities for near patient testing will not be needed for every diagnostic or monitoring procedure in primary care. Electronic links enable rapid transmission of results from a hospital laboratory to a doctor's desk. In Britain this facility will be further enhanced with the advent of the new practice computer systems, which should enable results to be filed electronically and remotely in patients' records, thus reducing the costs and errors of transcription. However, unlike near patient testing, rapid electronic links will not enable clinicians to use test results in immediate management decisions.

The list of near patient tests that are potentially relevant to making urgent clinical decisions is substantial: tests for antibodies to Helicobacter pylori,7 C reactive protein,8 and cardiac troponin T9 10 are already available, and many tests—such as for glycated proteins and for numerous drugs—are under development. An immediate result from a near patient test for C reactive protein might enable a doctor to avoid unnecessary prescribing of an antibiotic (by distinguishing between viral and bacterial infection) or help in the differential diagnosis of acute abdominal pain.11 Near patient testing may also encourage doctors to be more discriminating in their choice of investigations, since the trend is towards developing devices that perform single rather than multiple tests.

In monitoring disease, near patient testing promises greater convenience to patients,12 improved therapeutic control (if results are presented during the consultation),13 and reduced overall health costs.14 However, the full potential of near patient testing can be exploited only by finding the clinical niches where its use would be most likely to influence practice beneficially14 and then finding mechanisms to enable its wider dissemination. This would go beyond the regular problems of implementing research findings, since for most general practices in Britain no method exists for funding such diagnostic testing.

No discussion on near patient testing can omit the importance of external quality assurance.15 This priority might be best met by a coherent policy to develop near patient testing in primary care in collaboration with hospital clinical chemists. Equipment provided by specialists and used by general practice staff who have undergone laboratory training, combined with external quality assurance from central laboratories, might prove the most durable model.

In many situations primary care physicians will continue to use the powerful diagnostic tool of waiting and seeing.16 However, the incremental use of fully evaluated near patient testing could help primary care to take its next logical evolutionary leap, to subsume the remaining functions of the hospital general physician within community settings.