Evidence-based laboratory medicine – from essentialism to consequentialism
Prof Andrea Rita Horvath, MD, PhD, FRCPath(UK), FRCPA
Prof Horvath is Director of Chemical Pathology in New South Wales Health Pathology at Prince of Wales Hospital in Sydney. She is conjoint professor at the University of New South Wales, honorary professor at the University of Sydney and at Macquarie University. She had multiple national and international leadership roles: President of the Hungarian Society of Laboratory Medicine, President of the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM); and Member of the Board of Directors of the American Association of Clinical Chemistry, currently named the Association of Diagnostic Laboratory Medicine (AACC/ADLM). She held the 20th and 10th position on The Pathologist’s Power List of the 100 Most Influential Pathology Professionals in 2015 and 2018, respectively. She was also one of the three senior editors of the 6th edition of the Tietz Textbook and the 8th edition of the Tietz Fundamentals of Clinical Chemistry and Molecular Diagnostics.
For 6 years she chaired the EBLM Committee of the International Federation of Clinical Chemistry and Laboratory Medicine and for 8 years she was vice chair of the EBLM Committee of AACC/ADLM. She was the founder and past chair of the Test Evaluation Working Group of EFLM. Currently she chairs an EFLM Task Force Group on Outcome-Based Analytical Performance Specifications for Tests, the AACB working party on harmonization of critical risk results and the AACB-RCPA working group on the preanalytical aspects of glucose testing. She is also member of AACB’s Executive Committee on Harmonisation.
Her key research interest and passion are evidence-based laboratory medicine (EBLM), evidence-based evaluation of biomarkers and effectiveness and safety of laboratory testing.
Abstract
Evidence-based laboratory medicine – from essentialism to consequentialism
Andrea Rita Horvath, NSW Health Pathology, Prince of Wales Hospital, Sydney
The practice of laboratory medicine, as any other discipline in health care, is guided by the four pillars of the Hippocratic ethical and moral principles of beneficence (doing good) and non-maleficence (doing no harm). This obligation requires us to take into account the patient’s autonomy and appropriately assess risks and probabilities when we balance harms and benefits of medical interventions. Justice or fairness, as the fourth pillar of medical ethics, refers to the moral obligation to act on the basis of fair adjudication between competing claims (i.e. what is good and fair for the patient and society as a whole, at a reasonable cost and that does not disadvantage others).
Philosophically and in practice, actions in healthcare, and within that in laboratory medicine, often follow the principles of essentialism (i.e. the quality of every action is judged by the action) and consequentialism (i.e. the quality of every action should be judged by its consequences). Patrick Bossuyt, a leading epidemiologist in evidence-based diagnostics, has translated these principles to laboratory medicine. Essentialism is the theory that the value of a medical test should be judged by the ‘trueness’ of its results. Consequentialism is the theory that the value of a medical test should be judged by the value of its consequences. Utilitarianism is a form of consequentialism; it says the best action is the one that brings about the highest increase in utility (benefit), often taking into consideration the needs of society and not just the patient (i.e. justice/fairness).
These basic moral principles and the consequentialist/utilitarian thinking are at the core of evidence-based laboratory medicine. Anyone practising consequentialism and utilitarianism faces at least three challenges: 1/ how to define what is of value; 2/ how to determine what the probability of various outcomes is, particularly in laboratory medicine where testing almost always has indirect impact on patient outcomes; 3/ how to compare the expected value of different courses of action. Answering these questions requires the synthesis, critical assessment, and judicious application of the most up to date scientific evidence to clinical practice and measuring its impact on relevant outcomes of care.
For decades laboratory professionals have been focusing on perfecting the analytical performance of laboratory tests (essentialism) based on the assumption that if a test has the highest possible analytical quality, then it will better guide medical decisions and ultimately lead to better patient outcomes. Whilst this is partly true, as evidenced by successful international and national efforts of standardisation and harmonisation of laboratory testing, and rigorous rules and complex quality management procedures for quality control and quality assurance, the emphasis has been disproportionately lower on the clinical performance and clinical effectiveness of testing (consequentialism). However, even lab tests of the highest analytical quality will not deliver value if they are used for the wrong clinical question, on the wrong patient (inappropriate assessment of pretest probability), at the wrong time (pre-preanalytical error at test ordering) or from the wrong sample (preanalytical errors at sample collection and processing), and if results are interpreted wrongly due to lack of well-designed clinical performance studies or decision or reference limits (postanalytical errors). Clinical guideline teams often overlook these aspects of testing which may result in misclassification of conditions, including misdiagnosis.
In my presentation I will describe the key principles and methods of practising evidence-based laboratory medicine and demonstrate with examples how analytical and clinical performance and clinical and cost-effectiveness of testing interact with one another in a cyclical framework that is driven by how the medical test is used in the clinical pathway. I will also demonstrate how the clinical performance of tests should be evaluated to provide realistic estimates of their diagnostic and prognostic accuracy and how this information can then be translated to analytical and preanalytical performance specifications that make tests fit for their intended purpose. I will highlight the role of laboratory professionals in providing more clinical evidence for the judicious use of laboratory tests that also meet the requirements of the new IVD regulation. I will illustrate with examples how the postanalytical aspects of our service could be improved through translating clinical performance to clinical effectiveness and how such evidence can be used in clinical guidelines for best laboratory practice.
My Roman lecture will focus on several topics and approaches that taught me throughout my 40 years in laboratory medicine of how to move from essentialism to consequentialism and utilitarianism and how these basic moral principles should drive our thinking and actions when designing and delivering services in our laboratories.