Biomarkers have been used in clinical medicine for decades. With the rise of genomics and other advances in molecular biology, biomarkersstudies have entered a whole new era and hold promise for early diagnosis and effective treatment of many diseases. A biomarker is acharacteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes or pharmacologicresponses to therapeutic intervention. There is increasing pressure to provide cost -effective healthcare based on "best practice." Consequently,new biomarkers are only likely to be introduced into routine clinical biochemistry departments if they are supported by a strong evidence baseand if the results will improve patient management and outcome. This requires convincing evidence of the benefits of introducing the new test,ideally reflected in fewer hospital admissions, fewer additional investigations and/or fewer clinic visits. Carefully designed audit and cost-benefitstudies in relevant patient groups must demonstrate that introducing the biomarker delivers an improved and more effective clinical pathway.From the laboratory perspective, preanalytical requirements must be thoroughly investigated at an early stage. Good stability of the biomarker inrelevant physiological matrices is essential to avoid the need for special processing. This article will focus on how these biomarkers have beenused in preventive medicine-diagnosis therapeutics and prognostics as well as public health and their current status in d practice. This article alsodescribes the major uses of biomarkers in clinical investigation. Careful assessment of the validity of biomarkers is required with respect to thestage of disease. Causes of variability in the measurement of biomarkers range from the individual laboratory. Issues that affect the analysis ofbiomarkers are discussed along recommendations on how to deal with bias and confounding
