Evidence-based medicine: its application to laboratory medicine

Demand management and test request rationalization

Demand for laboratory testing is increasing disproportionately to medical activity, and the tests involved are becoming increasingly complex. When this phenomenon is seen in parallel with declining teaching of laboratory medicine in the medical curriculum, a need emerges to manage demand to avoid unnecessary expenditure and improve the use of laboratory services: 'the right test in the right patient at the right time.' Various methods have been tried to manage demand, with success depending on the medical context, type of health service and preintervention situation. Because many factors contribute to demand, and the different settings in which these exist, it is not realistic to meta-analyse the studies and we are limited to trying to identify trends in results in particular situations. The studies suggest that education combined with facilitating interventions, such as feedback, prompts and changes to laboratory request forms are the most successful. From the perspective of a whole health service, it is important that results are not exaggerated by assessing benefits in terms of total rather than marginal cost. It would be desirable, although difficult, to include the impact on downstream clinical activity caused or avoided by the interventions. Advances in information and web technology may make the elusive goal of achieving substantial demand control more achievable.

Appropriateness of therapeutic drug monitoring for antidepressants in routine psychiatric inpatient care

Although there is sufficient evidence of the benefits of therapeutic drug monitoring (TDM) for optimizing antidepressant therapy, its current use in routine care is far from optimal. As a prerequisite for developing improvement strategies, the appropriateness of TDM use was investigated in a psychiatric hospital in which TDM is applied routinely to a large extent. A retrospective analysis of all patients admitted in 2003 with a unipolar depressive disorder was performed. Based on detailed chart review, for all TDM tests, the time of blood sample taking in relation to the medication process and the consequences of the TDM results for clinical decision making were analyzed. Altogether, 748 plasma levels were measured for antidepressants. The evaluation identified considerable inappropriate use of TDM. After a preceding change of dose, only the minority of TDM tests was performed within an optimum time interval. Overall, 30% of blood samples were taken too early, before steady state had been reached. The high number of repeat tests without preceding change of drug dose points to potentially redundant use. There also was evidence of underuse of TDM, as in many cases additional plasma level determinations might have been useful to speed up optimal dosing. Frequent discrepancies were found between the laboratory's recommendations and actual clinical decision making. Suggested dose changes were followed in only 30%. The findings clearly indicate the need for measures to improve the implementation of TDM in routine care. Based on the identified pattern of current TDM utilization and experiences from other fields of medicine, a combination of strategies, including both educational and electronic interventions, may have the greatest potential for improvement.

Appropriateness in programs for continuous quality improvement in clinical laboratories

BACKGROUND

External reviews and the accreditation of medical laboratories involve more than the mere assessment of conformance with standards for organisational processes. The new approaches to quality improvement suggest that, rather than using inspection to correct unusual errors, there should be more emphasis on improving the processes of health care to ensure that desired outcomes are produced. Appropriateness plays a key role in programs for quality improvement.

METHODS

Appropriateness in laboratory medicine can be assessed, and improved, through the governance of the entire testing process. This begins with test selection, proceeds through valuable pre-, intra- and post-analytical procedures, and concludes by assuring the correct interpretation and utilization of laboratory information.

RESULTS

The International Standard, specifically developed for medical laboratories (ISO 15189) recognizes the value of appropriate interpretation and advisory services, although it does not specify requirements for assessing appropriateness, requesting tests and interpreting results. The effectiveness of clinical laboratories can be assessed by using surrogate markers, which indicate physicians' satisfaction, and clinical audits. Effectiveness is also enhanced by stressing the importance of the technical and professional competence of evaluators.

CONCLUSIONS

Inappropriate laboratory utilization unjustifiably increases health care costs, can harm patients and perpetuates the vision of laboratory testing as a commodity. Improvement in laboratory appropriateness can be achieved by seeking a better relationship with physicians and by stressing the role of laboratory specialists in providing clinical advice for the selection of laboratory tests, and the interpretation and utilization of their results, thus leading to more satisfactory clinical outcomes.

Evidence-based laboratory medicine as a tool for continuous professional improvement

BACKGROUND

Evidence-based medicine (EBM), defined as "the conscientious, explicit, and judicious use of the current best evidence in making decisions about the care of patients," seems a tool (a "new paradigm") able to meet individual clinical experience with robust observations. EBM has been driven by the need to manage information overload by cost control and by public request for the best in diagnostics and treatment.

METHODS

The application of EBM in laboratory medicine or evidence-based laboratory medicine (EBLM) is aimed to advance clinical diagnosis by researching and disseminating new knowledge, combining methods from clinical epidemiology, statistics, and social science with the traditional pathophysiological molecular approach.

RESULTS

EBLM, by evaluating the role of diagnostic investigations in the clinical decision-making process with emphasis on measurable outcome, can help both in improving the quality of new scientific findings and in translating the results of good-quality research into everyday practice.

CONCLUSIONS

Since there is a need to integrate many educational tools to focus the strategy on promoting the implementation of best practices, the STARD proposal for robust diagnostic test primary studies, the presence of systematic reviews of high quality, and the development of valid guidelines based on the best scientific evidence may be useful to promote an a evidence-based culture for appropriateness, efficiency, and effectiveness in laboratory medicine.

Charting the course of medical laboratories in a changing environment

BACKGROUND

In recent decades, dramatic changes have occurred in the organization, number and type of tests, and role of medical laboratories in healthcare. The role of laboratory professionals has undergone a radical change, which calls for greater analytical accuracy, and more stringent test selection, and interpretation of results.

METHODS

The ancillary role of clinical laboratories in the past was analyzed in order to understand why the change has taken place, and to identify old and new areas in which laboratory information is largely used for improving upon decision making for treatment, and patient management.

RESULTS

The availability of real-time laboratory results and more effective tests, the enhanced clinical consulting role, the involvement in therapeutic decisions, the efforts to prevent rather than cure disease, the shift from anecdotal care to evidence-based medicine, and the assessment of outcome for laboratory tests have all contributed to the changing role and duties of medical laboratories.

CONCLUSIONS

Crucial elements in sustaining the changes in the role and contribution of medical laboratories to a high-quality healthcare are the ability of laboratory professionals to: guarantee the quality of laboratory tests irrespective of where they are performed; improve the quality of services; improve clinical outcomes; and perform joint clinical/laboratory research projects. A key factor in effecting the change has been the awareness of the importance of the knowledge and skills required for the new role of laboratory professionals.

Are laboratory investigations recommended in current medical practice guidelines supported by available evidence?

It has been suggested that evidence-based laboratory medicine (EBLM) could help to improve the pertinence and accuracy of medical guidelines. In order to demonstrate this, we have used an EBLM approach (i.e. a systematic review) to examine three recently published guidelines that gave quite conflicting recommendations regarding the use of laboratory variables in the management of primary non-small cell lung cancer patients. In recommending the routine measurement of serum albumin, and, to a lesser extent, that of serum calcium in the pre-therapeutic prognostic evaluation of the advanced disease, the American Thoracic Society and the European Respiratory Society were probably correct with regard to calcium but perhaps mistaken regarding albumin. Some of the recommendations of the European Group on Tumour Markers regarding the usefulness of routine measurements of tumour markers (carcinoembryonic antigen (CEA), cancer antigen 125 (CA 125), tissue-polypeptide antigen (TPA)) in the pre- and/or post-therapeutic prognostic evaluation can also be criticised. In addition, the latter society as well as the Société de Pneumologie de Langue Française did not even try to list laboratory variables, others than tumour markers, that would be useful to stratify patients participating in clinical trials (i.e. lactate dehydrogenase (LDH), albumin, calcium, blood cell count, etc.), and the laboratory variables listed by the two former societies were probably not the right ones in this context: in particular LDH and tumour markers (fragments of cytokeratin 19 (Cyfra 21-1), tissue-polypeptide-specific antigen (TPS), neuron-specific enolase (NSE)) were not mentioned. Most, if not all of these discrepancies in the current medical practice guidelines might have been avoided had an EBLM approach been used by the authors.

Screening for the early detection of disease, the need for evidence

BACKGROUND

Screening for the early detection of disease has had a spotted history. Structured approaches to the process of gathering and evaluating evidence, with the emphasis on well-controlled randomized studies, have greatly improved the beneficial potential of appropriate and effective screening. Good quality evidence will contribute to quality health care.

ISSUES

The volunteer participants in screening programs must give fully informed consent. This means that they must be presented with clear and accurate statements of the advantages and disadvantages of the screening program. Among the screening programs that have been conducted include hyperhomocysteinemia and coronary artery disease, Down's syndrome, Neonatal Group B streptococcal disease, Type 2 diabetes mellitus and endometrial cancer. The evidence in these studies has strengths and weaknesses as to how they support or oppose a particular intervention. The laboratory has a major role to play in establishing and validating standards of accuracy for diagnostic tests. Agreement on standards and their application does not mean the end of different interpretation and controversy.

CONCLUSIONS

Laboratory physicians and scientists will be very effective consultants if they have the best available, high quality evidence for the appropriate use of laboratory tests.

Overview of Evidence-based Medicine: Challenges for Evidence-based Laboratory Medicine

Evidence-based medicine (EBM) has been driven by the need to cope with information overload, by cost-control, and by a public impatient for the best in diagnostics and treatment. Clinical guidelines, care maps, and outcome measures are quality improvement tools for the appropriateness, efficiency, and effectiveness of health services. Although they are imperfect, their value increases with the quality of the evidence they incorporate. Laboratory professionals must direct more effort to demonstrating the impact of laboratory tests on a greater variety of clinical outcomes. Laboratory and clinical practitioners must be familiar with many of the accessible electronic and paper tools for searching for evidence. Detailed statistical and epidemiologic knowledge is not essential, but critical appraisal skills and a competent understanding of the strengths and weaknesses of systematic review and metaanalysis are necessary. Overemphasis on complexity and failure to recognize time limitations are major barriers to translating EBM into everyday practice. Emphasizing and practicing the role of the laboratory professional as a skilled clinical consultant strongly grounded in evidence as well, in addition to better integration of laboratory and clinical information and improved laboratory reports will overcome most barriers. There is a poverty of good, primary studies of test evaluations. Institution of more consistent standards for the design and reporting of studies on diagnostic accuracy should improve the situation. If nothing else, systematic reviews have demonstrated the need for more good-quality primary research in laboratory medicine.