Biological markers or ‘biomarkers’ of organ damage and dysfunction occupy a central position in the armamentarium of the clinician that is used for the screening, diagnosis and management of disease. Our knowledge of the pathophysiological basis of individual diseases continues to increase inexorably and the discoveries emanating from the Human Genome Project are set to enhance this knowledge immeasurably. Understanding the aetiopathogenesis of changes that take place in individual tissues, organs or compartments of the body can help in the search for markers that reflect these changes. Some of these changes may be directly related to the pathological abnormality while others might be a secondary consequence of the abnormality.

Basic research into the pathophysiology of a disease provides the foundation of knowledge that can lead to the discovery of valuable biomarkers. This foundation can also act as the starting point for the discovery of pharmaceutical interventions. Increasingly, with a more systematic approach to biomarker development and drug discovery, we are seeing the measurement of the biomarker playing a greater role in monitoring the efficacy and/or side effects of the therapeutic intervention. From a clinical standpoint, this can have a major benefit in assessing compliance with therapy, which is acknowledged to be one of the key determinants of efficacy, especially when there is no other ready means to judge the patient's response.

The discovery of a new biomarker is complemented by the development and validation of appropriate analytical technology.