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Point-of-care testing seems to have the potential to impact positively on patient care, and may result in substantial economic savings in the critically ill patient in a variety of settings
Ulf Martin Schilling MD PhD
Center of Clinical and Experimental Medicine,
University of Linköping and Department of Accidents and Emergencies,
Linköping University Hospital, Linköping, Sweden
Point-of-care testing (POCT) is by definition any testing conducted at, or near, the patient’s bed. In practical use, the term POCT is commonly restricted to laboratory analysis in this setting. Since the introduction of POCT, it has been heavily scrutinised and the use of this technology in a multitude of potential applications has been extensively discussed among clinicians and laboratory physicians. A multitude of classical and modern studies arguing for and against POCT can be found.
Several aspects of POCT such as reliability and quality of analysis, ergonomic applicability in different settings, potential and actual impact on patient care, and costs of POCT have been discussed repeatedly in studies both pro- and against the use of POCT in different settings, and it seems that – as so often in medicine – a final conclusion regarding the value of POCT is impossible to be reached.
However, POCT is used extensively in private, medical and critical care, ranging from easy-to-use devices such as over-the-counter pregnancy tests, glucose-self monitoring tests for diabetics, coagulation self-monitoring devices, and alcometers for public and police use, to simple carbon dioxide tests to confirm adequate intubation, urinary drug tests, rapid infection essays for malaria, urinary tract infection, pre-hospital devices for exclusion of myocardial infarction, rapid D-dimer testing for deep vein thrombosis and pulmonary embolism, finger-tip-lactate in potential sepsis, and rapid blood gas and electrolyte analysis for the potentially critically ill, and many other tests. With such an extensive use of POCT and the multitude of products available, the discussion regarding the use, of not to use, or even misuse of, POCT might seem academic even if not completely out of date.
In the clinical setting, there are four main factors to be considered about point of care:
(1) Laboratory aspects, that is, standard and reliability of analysis, and compatibility of local systems and IT infrastructure
(2) ergonomic aspects for use by staff, that is, ease and safety of use
(3) clinical aspects, such as impact on patient care and safety, and
(4) economic aspects.
In modern healthcare, the acceptance of medical devices is heavily regulated and extensive testing has to be performed by the manufacturer before any product – including POCT – is cleared for the market by health authorities and a rigorous continuing quality control is demanded from the producers. Due to this, and the intense competition in the market, device-related quality problems in approved POCT devices are rare.
Often, such problems are related to ergonomic issues. POCT devices are often used by staff who have limited training in laboratory analysis, a fact often discussed in the laboratory setting and considered to be a major problem. It is argued that the lack of training of analysing staff might negatively interfere with the accuracy of results, potentially misleading the clinical judgment of physicians relying on these faulty values. To counter this potential problem, the design of POCT analysers is commonly user-friendly with more or less automatic systems requiring a minimum of maintenance.
Furthermore, the use of these automatic devices requires a certain level of chemical stability and standardisation of any analytic material, usually achieved by automatic assembly of standardised calibrated analytical kits in contrast to manual calibration and refill of larger centralised analysers. By the use of, for example, cartridges or standardised syringes, automatic readers and interconnectivity to hospital systems, POCT designers essentially reduce the manual steps to the retrieval of the sample and the filling of the analysing device, that is, the pre-analytical steps. Mistakes made during the pre-analytic steps will affect any analysis regardless of whether it is performed by POCT or via a central laboratory.
As a result, POCT is subjected to fewer manual steps than central analysis and, as a consequence, is less prone to manual mistakes, as well as being less time consuming (Table 1).
Does POCT improve quality of care and/or patient safety? To answer this question, quality of care must be defined in an appropriate way. In the critically ill, quality of care could be defined as:
These aspects will be discussed in the potentially critically ill, that is, patients suffering from chest pain, acute neurological deficit and potential sepsis.
POCT in chest pain
Patients presenting with chest pain symptoms account for approximately 15% of all emergency department (ED) visits. A total of 70% of patients who are admitted to the ED with chest pain are not suffering from acute coronary syndromes (ACS).1,2 Conversely, a non-trivial number of patients with ACS are mistakenly discharged from the ED, resulting in avoidable patient mortality. The analysis of cardiac troponins is now the laboratory gold-standard in ruling out acute myocardial infarction, and current guidelines recommend Tn measurements be made available to physicians within 30 minutes of sample collection.2,3 Delays in treatment are commonly associated with an increased probability of adverse outcomes.4–6 POCT has been shown to increase the speed at which positive cases of ACS are identified accurately,7,8 and safe, rapid rule-out protocols have been established.9
POCT in neurological deficit
Modern treatment of ischaemic stroke with thrombolysis and percutaneous intervention has increased long-term survival and reduced morbidity. With increasing risk of bleeding with delayed thrombolysis, any delays in diagnosis and treatment have to be minimised.10 Besides CT-scanning, the immediate assessment of a patient’s coagulation status is necessary to ensure timely and safe thrombolysis. Delays in laboratory results were recently identified as one of the major barriers to the early initiation of thrombolysis therapy in a simulation-based approach.11 Studies have clearly shown the benefits of POCT in the management of stroke, as POCT can significantly increase the incidence of early thrombolysis, positively impacting on patient care through reduced turnaround time (TAT).12,13 Tight glucose monitoring and control in patients with neurologic deficit and in stroke positively impacts patient care, and is commonly performed through the use POCT devices in the clinical setting.14,15
POCT in potential sepsis
Sepsis is a life-threatening disease and remains the primary cause of death from infection and one of the leading causes of death in the world.16 The clinical signs and symptoms of sepsis are non-specific, often resulting in delayed diagnosis and treatment, which, in turn, can have a profound negative effect on outcomes. Among other biomarkers, blood lactate levels are a sensitive marker of impaired tissue perfusion in patients with suspected sepsis and are predictive of mortality. Furthermore, they are a valid method to direct therapy in such patients as recommended by recent guidelines.17,18 The initiation of goal-directed therapy within the first three to six hours of presentation to the ED improves mortality rates by 16%.18–20 Additionally, decreases in lactate levels of 20%, every two hours for the first eight hours have been associated with a 9.6% reduction in mortality.21 POCT technologies for measuring lactate are available, and allow for results being available to physicians up to 151 minutes faster than if analysed by other methods.22
Economic impact of POCT on patient care
A number of factors influence the economic impact of POCT. These can be divided into direct and indirect costs of laboratory analysis, and into the economic impact of the quality and timeliness of care as mentioned above.
The cost per POCT analysis can be compared directly to the costs of core laboratory analysis. Depending on the local setting and standard at the core laboratory as by national regulations, costs of laboratory analysis are based on staffing, costs for chemical reagents, and costs for the machines. If the laboratory is outsourced or centralised in another hospital, there are further costs for transport. These differences in costs are easy to calculate, and tend to vary between larger and smaller hospitals due to the need of staffing for the core-laboratory 24/7. Smaller units will benefit from POCT by savings in direct costs, whereas larger hospitals will tend to find equal, or even slightly higher, costs per analysis compared with POCT and core laboratory.
The indirect costs of laboratory analyses are related to delays in time to result, diagnosis and therapy, which, in turn, contribute to patient outcomes with resulting costs, need for transport in between hospitals in case of clinical doubt, unnecessary admission due to external targets of limitations of time in emergency departments, overcrowding, resulting in the need of increased staffing, and the potential need for multiple analysis if different systems are used in the same hospital. These costs are higher than direct costs of analysis, with staffing resulting in the highest cost in modern healthcare; the overall economic impact of POCT in the indirect costs was as shown as early as 1999.23
Short TATs and no requirement for dedicated laboratory staff for routine analyses are the major advantages of POCT. The TAT for POCT is, on average, 46 minutes faster than central laboratory analysis even in the best settings, minimising transport times, and with a reasonable level of accuracy.24–27 Any delay in time can be translated into economic impact, as each minute of waiting time for a patient will result in increased need of staffing. In a Swedish study, the costs per waiting minute per patient were €1.25 (1.5US$), or per 46 minutes at €57.5 per patient.28 In another study, the use of POCT during stabilisation of patients before inter-hospital transfer resulted in time savings of approximately 100 CDN/transfer, and substantial time savings.29 These costs, however, are dependent on the local setting and would have to be determined for each individual hospital.
As delayed diagnosis and therapy increase morbidity, mortality and costs in the critically ill, ‘time is money’. Not only can unnecessary admissions be avoided by using POCT, as shown by a 20% reduction in admission on patients with chest pain in the UK setting,30 but the introduction of POCT in the cardiac observation unit has also been shown to result in 25% cost reduction and reduction in length of stay, with the main savings resulting from reduction of boarding, admission to further departments, and procedures.31 Even in less industrialised countries, POCT resulted in elevated direct costs in screening for immunodeficiency but in improved survival at a final cost of 500 US$/year of life saved.32
A recent review of more than 30 studies revealed the positive economic impact of a multitude of POCT in several clinical settings for the critically ill in cardiac surgery (saving on blood products 56%), the neonatal ICU (saves 8.3% per patient), the cardiac observation unit (25% savings due to POCT), the paediatric ED (liberating substantial ED-capacity during infection periods), and at the ED (21.7% cost reduction by tetanus testing).33
Interestingly, the authors had to conclude that POCT alone would result in limited savings only as long as clinical pathways were not adapted to fully benefit from the main advantages of the technology in reduced TAT, that is, if the potential savings in time were not translated into savings of indirect costs. This conclusion is consistent with the findings of Asha et al. in chest pain patients in the ED-setting, where the introduction of POCT did result in potential savings by earlier decision-making and consecutive disposition of the patients, with a slight increase in cost per analysis.34 In most studies revealing an economic benefit from the introduction of POCT, a revision of clinical pathways during implementation of the new technology has been made. Due to the inherent differences among hospitals, multicentre studies, such as the RATPAC trial,35 tend to have differing results regarding the economic impact of POCT, and the direct transfer of the findings of the literature to the local setting might be difficult.
POCT is subjected to similar regulations as central laboratory testing, and results are equally reliable. Shorter TATs for POCT reduce delays in diagnosis, treatment and discharge of patients. POCT seems to have the potential to impact positively on patient care, and may result in substantial economic savings in the critically ill patient in a variety of settings. To fully realise the inherent economic potential of POCT, however, clinical pathways have to be adapted to exploit its benefits.