Clinical and diagnostic importance of proteinuria: a review

Abstract

A continual function of the kidney is essential to good health playing active roles in urine formation. Under normal physiological state urine is expected to be protein free. The production of protein free urine is exclusively carried out by the kidney nephrons. Nephrons are structured to perform an important role of filtration and reabsorption. Therefore, a defective or diseased kidney is associated with defective reabsorption mechanisms and an indication of injured nephrons. The appearance of proteins in urine (proteinuria) is a strong indicator of kidney disease. The assessment of proteinuria is clinically and diagnostically an important index in renal function generally and particularly that of nephrons. However, pathological proteinuria may be due to various factors or diseases. It is has been shown that diabetis mellitus, cardiovascular disease and hypertension could provoke secondary kidney problems. Proteinuria is also significant in some non-pathological cases such as pregnancy and static proteinuria found among military men. Various methods are used for the screening and detection of pathological and non-pathological proteinuria; the methods have their individual merit and demerits. Researchers had made significant contributions in improving the traditional techniques used in detecting and estimating urine protein. Current research in proteomics and genomics science with the development of new techniques in chromatography. (2D-gel chromatography) had produced interesting and promising results in discovery of other classes of urine proteins that could be used as biomarkers of renal disease. This review examines the clinical and diagnostic importance of proteinuria and available techniques. It is hoped that this paper would throw more light into this important but taken-for-granted diagnostic tool in laboratory medicine