Laboratory investigations in patient care

The accurate diagnosis and management of disease almost always involves the judicious use of laboratory investigation. The increasing sophistication, diversity and expense of laboratory tests must however impose a moratorium on the use of these tests. This article reviews the justification for tests in clinical biochemistry and the general classes and varieties of tests available. Furthermore, factors that may make a test result normal or abnormal are discussed, with emphasis on the mechanisms, other than disease, that may have contributed to an unexpected result. The review ends with a discussion on the implications and modalities for extending clinical biochemical tests from the laboratories locations closer to the patient's bedside.