Laboratory medicine using test results

Clinical Chemistry, Laboratory Medicine, and Evidence-Based Laboratory Medicine In this chapter, we review the new influences on clinical chemistry and laboratory medicine from the fields of cfinical epidemiology and evidence-based medicine (EBM). Cfinical epidemiologists have developed study designs to quantify the diagnostic accuracy of the tests developed in laboratory medicine, and study methods to evaluate the effect and value of laboratory testing in healthcare. Practitioners of EBM focus on use of the best available evidence from such well-designed studies in the care of individual patients. EBM rephrases problems in the clinical care of patients as structured clinical questions, looks for the available evidence, evaluates the quality of cfinical studies, evaluates the clinical implications of the results, and provides tools to help clinicians optimally use those results in the care of individual patients. 

The identification of a clinical goal provides the foundation of the service provided by the healthcare professional. In the area of laboratory medicine, as described later in this chapter, the goal can be expressed in terms of answering a clinical question appropriate laboratory investigations help to answer the question." Knowledge of the characteristics of these investigations is needed to decide which test to use, when to use it, and how to interpret the results. 

Dasgupta A. Review of abnormal laboratory test results and toxic effects due to use of herbal medicines. Am J Clin Pathol 2003 120 127-37. 

In the context of drug discovery, computational methods do not add value unless they can achieve practical results. Results must be produced quickly enough so that they can influence decision making in chemical synthesis. Most importantly, computational methods must be accurate enough to maintain the trust of the medicinal chemist. Without this trust, computational predictions will rarely be tested in the laboratory, which will then prevent the generation of critical data useful for improving the original predictions. 

The objectives of preclinical testing to support development of new medicines are to detect and characterize unwanted actions, whether inherently toxic or secondary to pharmacological effects of the substance and its pharmacokinetics, to exclude predicted harmful effects, and as far as possible to reveal other, potentially valuable actions. All this must be done in such a way that the results are both scientifically and administratively useful, as GLP and GMP considerations are essential, and the duration and costs of the of the studies are minimized. In this way the necessary resources of scientists, experimental animals, and laboratory facilities can be minimized in order to make the development of products to treat sick patients as efficient, humane, speedy, and economical as possible. 

Optimal use of the laboratory requires examination of both the cost of obtaining the result and the value or quahty of the information obtained. Determining the quahty of various procedures in medicine has been a subject of increasing interest over the last 2 decades. Some key aspects of value received are the amount of improvement in health care, the extent to which testing is consistent with the wishes and expectations of patients, and the degree to which testing addresses social concerns as embodied in laws and regulations. 

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