Chapter 68 Alix J.E. Carter Technology has evolved such that many laboratory-based analyses can now be performed on portable (sometimes hand-held) devices, allowing testing at the point of care. Point-of-care testing (POC) is emerging across many settings in health care. Broadly addressing the setting of emergency care, the advantages may include reduction in time to treatment for emergency conditions, and improved flow through increasingly congested emergency departments. There is discussion of the potential benefits offered by introducing POC testing to the prehospital setting. Advantages may include earlier initiation of life-saving treatment, as well as enabling more informed destination choices. The wide variety of POC testing options may save money and make the practice of EMS more efficient and effective. However, it is a balance of costs and benefits. The discussion contains three subissues: what is the reliability of the emerging technology of POC, can that reliability translate to rugged prehospital conditions, and, most importantly, will it make a difference to patients? There may be a fourth issue in the subtext: what this means to the scope and education of EMS professionals. There are a number of advantages, at both patient and system level. POC may allow more targeted and earlier intervention. This may enable more appropriate regionalized destination strategies. It may even stretch to evidence-based non-transport, and the application of new therapies in the field. POC may have a particular role in community paramedicine (Box 68.1). There are some disadvantages as well. POC may carry medicolegal risk, with a need for development of a robust quality assurance/improvement plan. There is concern for scope creep, and that POC represents just another fancy toy. There is skepticism that POC testing will contribute to EMS being used as doctor or nurse replacement in the reform of health care. Furthermore, the incentive to “stay and play” must be considered, and whether the possibility of longer scene time would be mitigated by more efficient overall system utilization is unknown. The implications for a change in the training of EMS providers, to include a foundation of pathophysiology sufficient to troubleshoot and understand the implications of positive and negative tests, must be a factor in the decision to introduce POC testing. A good diagnostic test moves the clinician from diagnostic uncertainty to greater certainty. If the pretest probability of disease is low or high enough, there is no point in doing a test that costs money and may carry risk – at a minimum, the risk of false positive (or negative), at worst, a risk of harm by adverse reaction. For each test, there is a need to ascertain the sensitivity and specificity, and/or positive and negative predictive value. The issue of whether the result will change clinician actions is also important. The presence (or absence) of action may be on the basis of evidence-based criteria, local practice, and/or system design. For example, if field trauma triage protocols are not structured to incorporate the results of a lactate or cranial scanning for hemorrhage, there is no sense in putting these tools in the field. They are expensive, they need maintaining, and it will be frustrating for the field provider to produce data on which he or she cannot act. The system must consider an estimate of the upfront and ongoing costs, and weigh these against other system priorities. Consider whether the test will work in an ambulance. On a system level, assess the potential effect on performance or process measures, and the capacity of the system to handle required changes to infrastructure, for example training, follow-up, CQI infrastructure. Multiple factors go into the decision as to whether introducing a given POC is right for your EMS system (Box 68.2). Medical devices in the United States are regulated by Food and Drug Administration (FDA). POC tests, as with other laboratory testing devices, fall under the FDA Clinical Laboratory Improvement Amendments (CLIA). CLIA sets standards for quality assurance and categorizes testing based on how complex it is for the analyst to run the test (e.g. training, knowledge, interpretation). The categorization (waived, moderate, or high complexity) has implications for who can use the tests, and the quality oversight infrastructure required. Box 68.3 provides more detail on the implications, and a note is made in the individual discussion as to the CLIA complexity category of a POC test (www.fda.gov/Medical Devices/DeviceRegulation andGuidance/IVDRegulatory Assistance/ucm124105.htm). EMS systems in other settings need to investigate local regulations as they apply to medical devices. In all settings, the general discussion in this chapter with regard to important questions and infrastructure still applies.
Point-of-care testing in EMS
Introduction
Is POC right for EMS?
Is this particular test right for my service?
Is the POC test valid and reliable?
How practical is this POC test?
Specific POC tests for consideration in the EMS setting