Study of Renal Function in the Differential Diagnosis of Kidney Disease

Abstract

Ever since Richard Bright's (1827) discovery that precipitation in urine heated on a spoon over a candle was diagnostic of kidney disease various tests have been used to assess renal function. For a long time the only aim of these tests was the quantification of the functional residue of the diseased organ, because until relatively recently nothing more effective than a low-protein, salt-free diet could be prescribed for Bright's disease. But now at least some forms of renal parenchymatous disease are amenable to treatment, and their differential diagnosis has become a practical necessity. Since for the past 50 to 70 years the classification of renal diseases has been based on morphology, it is understandable that attempts to obtain renal tissue for morphological study was the first line of approach in differential diagnosis. However, just as a pathogenic agent affects the morphology of cells and tissues so it affects their function. By learning how to recognize and interpret functional changes patterns of abnormality will be obtained which may be as diagnostic as abnormal patterns in morphology. © 1971, British Medical Journal Publishing Group. All rights reserved.