To explain the challenges of POCT use from different perspectives, Dr. Ulf Martin Schilling (Consultant Emergency Medicine, University Hospital Link?ping, Sweden), Dr. Andrei Tintu (Clinical Chemist/Laboratory Data Officer, Erasmus University Medical Center, Rotterdam, The Netherlands), and Professor Suzanne Bench (London South Bank University and Professor of Critical Care Nursing at the Royal National Orthopaedic Hospital) presented their views at the Clinical Chemistry and Laboratory Medicine Conference during the 23rd IFCC-EFLM European Conference.
Emergency physicians routinely deal with acutely ill patients in whom the time to diagnosis and treatment can have a direct impact on their health and outcomes. If a patient is unconscious, clinicians are unable to obtain a medical history or detailed information about the events that led to the hospitalization.
In such cases, physicians typically navigate a range of obvious potential causes of the clinical presentation. For example, is the patient's airway open? Is it difficult to breathe? Are there problems with circulation, such as a stroke or heart attack? Are there signs of trauma or seizures? If there is no obvious reason for the patient's state, a more detailed investigation is needed. According to Dr. Martin Schilling, the cause of a patient's unconsciousness is usually "70% metabolic and 30% structural."
Pre-analytical variability is a key cause of poor laboratory diagnostic quality, shown to cause more than 60% of all laboratory errors. Similarly, preanalytical variability is critical in POCT. For example, exposure of a blood gas sample to air results in gas exchange between the air and the sample. This can result in measurements of different gases that do not reflect the patient's physiologic levels, Schilling notes, adding that "Na may be diluted if the sample is taken from the same arm that receives the IV". He reminds us that potassium levels are usually elevated in hemolyzed samples.
Inaccurate device results could lead to misdiagnosis
Professor Suzanne Bench, professor of critical care nursing at London South Bank University and the Royal National Orthopaedic Hospital
In the stressful environments of the emergency department and intensive care unit, there is a potential risk of misidentifying samples from different patients, which could lead to the analysis of the wrong sample and leading to the communication of incorrect values. These types of preanalytical errors that lead to inaccurate results can lead to misdiagnosis and possibly even incorrect treatment. POCT results can help support different potential diagnoses and may indicate which laboratory tests or imaging techniques are needed to make a definitive diagnosis and initiate appropriate treatment. However, this is only useful if the POCT results are accurate, according to Schilling, who suggested that "we know that even by accreditation standards, one in 20 results is abnormal.
Critical care nurses typically remain at the patient's bedside, providing physical and psychological care and support to relatives, as well as managing complex equipment. According to Prof. Suzanne Bench, this requires "effective communication, supervision of junior colleagues and maintenance of accurate documentation within the wider healthcare team.
Nurses are the biggest users of POCT equipment
Research suggests that nurses value POCT because it can "help speed up decision-making and delivery," but Bench acknowledges that POCT can impact nursing workload and time management. In a focus group discussion with A&E and critical care nurses in the UK, Bench revealed that "nurses are the biggest users of POCT in critical care". Nurses have a major responsibility for cleaning and quality control of POCT equipment, especially in out-of-hours and small hospitals. Training in these operations is essential. Inaccurate results may result if the equipment is not properly maintained.
Nurses said that training is necessary to ensure that they understand the entire process, such as how to ensure that an accurate sample is obtained? Why is this critical? and how to properly analyze the sample? Nurses were also concerned about how POCT affects patient experience and health outcomes.
POCT devices typically require smaller blood samples than larger laboratory instruments. With frequent monitoring of acutely ill patients, the volume of blood drawn can become large, potentially leading to anemia and, in extreme cases, the need for blood transfusions. This problem is exacerbated by pre-analytical errors, which is another reason why diagnostic sampling needs to be done "right the first time".
Frequent collection from patients also raises concerns about infection control and patient comfort, Bench noted, noting that "the time spent on POCT also impacts other aspects of care delivery and can lead to missed care for patients and families. For example, if local POCT equipment is unavailable, nurses may have to leave the patient and find an alternative instrument, possibly at a distance. The knock-on effect: other nurses in the department may have to reassign tasks to ensure coverage in the absence of their colleagues. Therefore, having a POCT system that provides reliable results is critical to critical care.
Quality management of POCT equipment
POCT equipment is an analytical instrument that falls under the umbrella of quality management in hospital laboratories, but is widely distributed in many locations across different hospital departments. This creates challenges in maintaining the equipment and meeting the standard recommended results.
Often, users of POCT instruments are not specialists in the full range of medical tests, but rather medical staff who use these instruments on an ad hoc basis. Therefore, instruments need to be fast and easy to use and provide reliable results. Training clinical staff to use POCT instruments is an important part of the laboratory work in many hospitals.
Dr. Andrei Tintu used the example of the Erasmus University Medical Center (4,500 POCT users) to show that the number of users that need to be trained and the large number of POCT devices available makes it difficult to provide training. This is an additional workload for clinical laboratories to undertake, Tintu commented, adding that in theory, the easier the POCT instrument is to use, the simpler the training requirements should be. This could help make clinical laboratories more efficient in their operations and reduce costs.
Clinical Staff Education and Training
Tintu said that given the number of employees and the high turnover rate, it can be challenging to maintain accurate records for compliance purposes to determine which employees are trained to use a particular device. Training employees on the POCT testing process and how pre-analytical factors affect sample quality and the reliability of analytical results is another important responsibility of the laboratory. This helps ensure early availability of results and reduces adverse events due to recollection of too little blood.
In addition, hospital POCT instruments must be validated for each sample type and test. By managing these devices, laboratories can quantify the accuracy and reliability of tests performed on these sample types, ensuring that staff receive high-quality results.
The reliability and accuracy of these tests has yet to be determined, increasing the risk of abnormal diagnostic results and, ultimately, the potential for patient harm. To manage the use of such unvalidated tests, Tintu believes the best solution is strong communication between the laboratory and the clinical team. By the lab listening to the needs of POCT users, he believes further services can be provided to increase the satisfaction of these users and ultimately improve patient care. Clearly, different groups of healthcare professionals have different perspectives on what a POCT should offer.
What should or could a POCT device provide?
Blood collection devices have evolved with the requirements of traditional diagnostic laboratory analyzers and therefore are not optimized for POCT devices, which are relatively new. The blood collection process needs to be designed and standardized to meet the different requirements of these devices. This will help to eliminate non-standardized practical methods used by healthcare professionals to solve problems identified in real-world clinical situations.
The current COVID-19 reminds us that safety is also important when considering POCT, and that infection control affects patient and staff safety. Managing acute cases is increasingly dependent on POCT equipment maintained by healthcare scientists, operated by nurses (and others), and the results of immediate action by medical staff. However, despite good equipment maintenance and user training, sample quality and pre-analytical errors can adversely affect the accuracy of results