Both the Canadian Society of Clinical Chemists (CSCC) and AACC have recently issued recommendations for how laboratories can take an active role in ensuring robust quality for point-of-care-testing (POCT) performed by their organizations (1,2). Recommendations include either direct oversight of all POCT or establishing an interdisciplinary committee.
In the Canadian province of Alberta, laboratory oversight of POCT performed by ambulance teams has been inconsistent (3). However, work is underway to better understand current POCT workflows and POCT-related challenges for these teams. This article provides an overview of what we have learned to date and proposes a standard for POCT performed by ambulance teams in Alberta and elsewhere.
Ambulance Services in Alberta
As a large province that covers 254,825 square miles (660,000 square kilometers)—including large areas of wilderness—Alberta relies heavily on ambulance teams to provide its population with emergency and critical care outside of hospitals. The full fleet includes more than 500 ground ambulances, 11 airplanes, 8 helicopters, and a mobile stroke unit. The majority of the province’s ambulance teams perform some form of POCT in order to allow earlier, more effective patient interventions.
Ground ambulance teams almost exclusively use small, portable glucose meters (such as the Roche Accu-Chek Performa), while most air ambulance teams use hand-held Abbott i-STAT1/i-STAT Alinity blood analyzers. The mobile stroke unit relies on four different POCT systems: a Performa meter, an i-STAT1, a Roche CoaguChek XS Pro prothrombin time/international normalized ratio (PT/INR) meter, and a Sysmex pocH-100i hematology analyzer.
POCT Workflows in Ambulances
POCT workflows for Alberta’s ambulance teams are similar across air and ground units (3), and they typically encompass three phases (Figure 1). Despite the similarity in workflows, ambulance teams throughout the province have adopted heterogeneous approaches to each testing phase. For example, validation of POCT devices and reagents prior to use may include calibration verification, quality control testing, patient sample comparisons with the laboratory, and/or electronic simulator testing.
See Figure 1 in CLN May PDF
The validation may be done by emergency medical services (EMS) personnel, laboratory personnel, or a combination of both. The source of this heterogeneity is multifold and includes operational silos within the healthcare system, varied oversight of POCT in EMS programs by laboratories across the province, and a lack of provincial, national, and international guidelines for POCT performed by ambulance teams.
POCT Challenges in the Mobile Environment
Even in the most ordinary circumstances, POCT presents laboratorians with special concerns, from documenting test results to standardizing methods with the central laboratory. For ambulance teams in Alberta, the nature of the patient care environment creates a host of additional, unique considerations. These challenges include communication difficulties, temperature extremes, other environmental constraints, lack of backup testing, confounders to POCT result interpretation, and more (3, 4). Others have documented similar challenges for ambulance teams elsewhere (5–7).
Communication. Alberta’s ambulance teams attend to a variety of patients with communication difficulties. Some patients may be unconscious or incoherent, while others may be unable to communicate effectively in the absence of a language interpreter. These communication difficulties pose several issues to performing POCT.
First, the ambulance team may be unable to ascertain the medical history of the patient and whether any of it is relevant to the testing that will be performed. For example, has the patient ingested any substances that may interfere with a particular POC assay and that may lead to inaccurate results? Second, a lack of positive patient identification prevents POCT results from making it into the patient’s permanent medical record. This may lead to compromised patient care further downstream, as some members of the healthcare team will receive an incomplete report of the patient’s EMS encounter.
Temperature extremes. Average winter daytime temperatures in Alberta range from 25°F to 32°F (-4°C to 0°C), while average nighttime temperatures range from 7°F to 18°F (-14°C to -8°C). Ambulance cabins quickly cool to temperatures near 32°F (0°C) when exposed to these winter conditions which, in turn, leads to the cooling of POCT devices below operational temperatures. Making matters worse, inexpensive and compact transport containers with active temperature control (e.g. thermo-modulating capability) that can keep POCT systems warm are not commercially available in Canada. In-house-developed transport containers provide some degree of insulation and slow down the cooling process, but they do not eliminate it completely. This forces ambulance teams to resort to inconvenient workarounds, including warming a POCT device inside a jacket and leaving a vehicle running while attending to a patient.
Temperature extremes may also impact POCT in other, less well-understood ways. Temperature-dependent analytical performance data for POCT systems is not readily available from manufacturers, but a handful of published studies indicate that clinically significant result changes may arise after a brief exposure to thermal stresses (8). The direction and magnitude of the change is dependent on the POCT system, the nature of the thermal stresses, and the length of exposure. Notably, the impact of repeated exposures to such stresses over a longer period of time is even less well characterized. Alberta has yet to undertake local studies that validate the short- and long-term performance of POCT systems under field conditions.
Other environmental constraints. Ambulance teams encounter additional environmental constraints: Lighting conditions are sometimes poor, a flat and stable testing surface is not always available, and the surrounding environment may be loud, stressful, and fast-paced.
These constraints enhance the risk of error in all phases of the POCT workflow. For example, a sample may be applied incorrectly to the POCT device, leading to either an inaccurate result or to a measurement error message. Patient identifiers may be manually entered into the POCT device with typos, leading to an incorrect association of the results with a different or nonexistent patient. Mistakes may also occur while reading the results off of a POCT device, especially with older devices that allow minimal control of screen backlighting.
Lack of backup testing. Alberta’s ambulance teams are often required to urgently administer life-saving or stabilizing interventions while on scene or in transit. POCT results may influence the decision around a particular intervention, such as a blood glucose result guiding hypoglycemia treatment. Despite this critical dependence on POCT, ambulance teams have limited options for backup testing in the event of a suspect result or a POCT system malfunction. A backup device is not routinely carried in most ambulances, owing to space constraints.
The urgency of the situation does not allow for a blood sample to be dropped off at a nearby laboratory. This leaves ambulance teams with three options: 1) retest the already collected sample to see if the repeat result is less suspect, 2) collect and test a new sample to see if the new result better matches available clinical information, and 3) troubleshoot and, if possible, fix the malfunctioning device. One or more of these approaches may prove to be successful in some instances, but at other times ambulance teams have to make their decision in the absence of a POCT result.
Confounders to result interpretation. POCT result interpretation may be confounded by many factors. For example, a difficult sample collection can lead to sample hemolysis, causing false increases or decreases in selected test results. Sample contamination with intravenous fluid can have similar effects. Medication administration may lead to testing interferences unless sufficient time has elapsed for the medication to be cleared from the patient’s system.
Laboratories commonly implement sophisticated rules in their laboratory information systems to flag suspect test results, and may also set up automatic reflex testing algorithms to better define the confounding factors. Alberta’s ambulance teams do not have access to such tools and instead use their training, experience, and intuition to identify any confounders to POCT result interpretation. This task grows in difficulty with the number of systems onboard an ambulance and the complexity of clinical intervention.
POCT Support and Guidance
Alberta has recently embarked on the design and implementation of standardized support programs for POCT throughout the province. The overall approach uses previously published POCT guidance documents (1, 2, 9) to develop a robust support framework with components that include training and competency, POCT system selection/validation/storage, connectivity, troubleshooting, quality assurance, documentation, and safety. The inclusion of features that address the special challenges of ambulance teams has been limited to date, but this is expected to change as local, national, and international guidelines become available on this topic.
Based on our experiences (3, 4, 8) and those of others (5-7), we propose in Table 1 a standard for POCT performed by ambulance teams in Alberta and elsewhere. This standard incorporates features that are already considered best practices for all POCT, as well as features that aim to mitigate the special challenges encountered by ambulance teams. For example, initial training and ongoing competency is considered an essential component of all POCT (1, 2, 9). We propose that this initial training and ongoing competency program incorporate a targeted section on best practices for sample collection and handling under the environmental constraints described earlier.
See Table 1 in CLN May PDF
A Call to Share Data
Our recommendations provide a starting point for supporting ambulance teams, but they may need to be revised as the evidence base for POCT in this setting continues to grow. Laboratories and ambulance teams should trial the recommendations for their feasibility and effectiveness, and should then share their experiences widely. This process will facilitate revision and further development of the proposed standard, and will ultimately lead to local, national, and/or international guidelines on POCT performed by ambulance teams.
Anna K. Füzéry, PhD, DABCC, FCACB, is a clinical biochemist, North Sector POCT Medical Lead for Alberta Precision Laboratories, and clinical associate professor in the department of laboratory medicine and pathology, University of Alberta in Edmonton, Alberta, Canada. +Email: [email protected]
Gerald J. Kost, MD, PhD, FAACC, is a professor emeritus in the department of pathology and laboratory medicine, School of Medicine, University of California, Davis. He is also a Fulbright Scholar, ASEAN Program, in Cambodia and the Philippines. +Email: [email protected]
References
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- Nichols JH, Alter D, Chen Y, et al. AACC guidance document on management of point-of-care testing. Clin Chem 2020;5:762-87.
- Füzéry AK, Kost GJ. Point-of-care testing practices, failure modes, and risk-mitigation strategies in Emergency Medical Services programs in the Canadian province of Alberta. Arch Pathol Lab Med 2020;144:1352-71.
- Füzéry AK, Bobyak J, Chang E, et al. Challenges of point-of-care testing in ambulances. J Appl Lab Med 2019;4:293-5.
- Di Serio F, Petronelli MA, Sammartino E. Laboratory testing during critical care transport: Point-of-care testing in air ambulances. Clin Chem Lab Med 2010;48:955-61.
- Rust MJ, Carlson NA, Nichols JH. A thermo-modulating container for transport and storage of glucose meters in a cold weather environment. Point of Care 2012;11:157-60.
- Peck Palmer OM, Wheeler SE, Plebani M, et al. Recognition of the prehospital preanalytical phase: Collaborative efforts between laboratory medicine and emergency medicine to ensure quality testing. Clin Chem 2020;66:998-1005.
- Louie RF, Ferguson WJ, Curtis CM, et al. The impact of environmental stress on diagnostic testing and implications for patient care during crisis response. In: Kost GJ, Curtis CM, eds. Global point of care: Strategies for disasters, emergencies, and public health resilience. Washington, DC: AACC Press-Elsevier 2015:293-306.
- Venner AA, Beach LA, Shea JL, et al. Quality assurance practices for point-of-care testing programs: Recommendations by the Canadian Society of Clinical Chemists point-of-care testing interest group. Clin Biochem 2020;88:11-7.