Point Of Care cardiac enzyme marker tests
I'm glad this came up, its been a pet topic of mine for a few weeks now.
In systems like ours here where there is a single EMS that basically government run and funded (partly) as are the hospitals, its much more feasible. The shift in cost from hospital to ambulance service is immense and this needs to be worked out somehow. Overall though, it improves the efficiency of pt care and reduces costs in this way. I think its just one of the many ways in which prehospital and ED care should be integrated to expedite treatment streamline the pt care.
There's little doubt that they improve turn around time (1) and shorten ED and CCU stays (2,3) to some degree without sacrificing (much) accuracy, and they're only getting quicker and more accurate. In about 7% of chest pain patients, the amount of time saved is thought to be clinically relevant (4), although it doesn't appear to affect the ultimate outcome or treatment. It stands to reason that if the whole process started in the prehospital arena these times would decrease, as would times involved in triage to appropriate facilities.
An article published in 2005 (5) argued that while the accuracy of the portable units approaches the accuracy of the labs (only to the extent that it is clinically the same for cardiac markers), no one unit does everything really required and no one method of portable analysis has yet emerged as superior.
Israel use pre-hospital cardiac markers although I've found it difficult to find much in the literature about them.
Over all I think it would be prudent to wait until cheaper testing units that do all (or as many as is possible) the tests required as stipulated in CHECKMATE study (6) are available to make it worthwhile. One day POC cardiac enzymes will be a big part of EMS and some promising work is being done with markers that appear earlier in the ischaemic cascade which would obviously be of much more use to us. Maybe waiting for this research to bear some fruit would be better. The technology and theory surrounding it, is all still a bit unsure to really go investing in large scale role outs of the technology in EMS as it stand at the moment.
1. P.O. Collinson, C. John, D.R.G. Cramp and R. Canepa-Anson, Prospective randomized controlled trial of point of care testing with central laboratory testing for cardiac enzyme measurement, Clin. Chem. 44 (1998), p. A69
2. A.J. Singer, J. Ardise, J. Gulla and J. Cangro, Point-of-care testing reduces length of stay in emergency department chest pain patients, Ann. Emerg. Med. 45 (2005), pp. 587–591.
3. C. Parvin, S. Lo and S. Deuser et al., Impact of point-of-care testing on patients' length of stay in a large emergency department, Clin Chem 42 (1996), pp. 711–717
4.Kendall J, Reeves B, Clancy M. Point of care testing: randomised controlled trial of clinical outcome. BMJ. 1998 April 4, 1998;316(7137):1052-7.
5.von Lode P. Point-of-care immunotesting: Approaching the analytical performance of central laboratory methods. Clinical Biochemistry.
2005;38(7):591-606.
6. L.K. Newby, A.B. Storrow, W.B. Gibler, J.L. Garvey, J.F. Tucker, A.l Kaplan, D.H. Schreiber, R.H. Tuttle, S.E. McNulty and E.M. Ohman , Bedside multimarker testing for risk stratification in chest pain units. The Chest Pain Evaluation by Creatine Kinase-MB, Myoglobin, and Troponin I (CHECKMATE) Study. Circulation 103 (2001), pp. 1832–1837
GOOD READING:
Yang Z, Min Zhou D. Cardiac markers and their point-of-care testing for diagnosis of acute myocardial infarction. Clinical Biochemistry. 2006;39(8):771-80.
Shebuski RJ. Utility of point-of-care diagnostic testing in patients with chest pain and suspected acute myocardial infarction. Current Opinion in Pharmacology. 2002;2(2):160-4.
