Urine Protein Selectivity / Clearance Profile ( IgG / Albumin Ratio ) / Protein Clearance Ratio

Immunology

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Description

Glomerular proteinuria results from increased transcapilliary passage of proteins and is characterised by the loss of plasma proteins equal to or greater than the molecular size of albumin. Quantitative assessment of glomerular function is possible through measurement of the renal clearance of proteins having different molecular sizes. Two proteins are used, usually IgG and albumin or alternatively, IgG and transferrin can be used [1,2]. Pathological processes causing glomerular proteinuria include immune complexes caused by SLE or post-streptococcal glomerulonephritis or membranous glomerulonephritis; deposition of abnormal substances caused by amyloidosis or diabetic glomerulosclerosis; chronic pyelonephritis, cardiovascular disease, pre-eclampsia, congenital renal malformations, and finally, renal disease of unknown aetiology: lipid nephrosis or idiopathic nephritic syndrome. The prescence of tubulointerstitial lesions in these diseases correlate with declining renal function [3].

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Indications

Assessment of Glomerular proteinuria.

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Sample Type

2mL Serum ( Gel 5mL Yellow tube ) + 20mL Urine ( preferably from a 24hr urine collection ). Requests from outside Sheffield: Transport at ambient temperature via Royal Mail or Courier.

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Reference Range

Ratio <0.16 indicates a reversible condition/selective proteinuria.Ratio >0.16 indicates renal disease that may not respond to treatment.The proteinuria of pre-eclampsia typically shows a clearance ratio of between 0.2 and 0.4, yet is fully reversible.

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Turnaround Time

Within 5 days

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Testing Frequency

As requested

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References

Bergon E, Granados R, Fernandez-Segoviano P, Miravalles E, Bergon M. Classification of renal proteinuria: a simple algorithm. Clin Chem Lab Med. 2002. 40:1143-1150. [Ref 1]Russo LM, Bakris GL, Comper WD. Renal handling of albumin: a critical review of basic concepts and perspective. Am J Kidney Dis. 2002. 39:899-919. [Ref 2]Woo KT, Lau YK. Proteinuria: clinical significance and basis for therapy. Singapore Med J. 2001. 42:385-389. [Ref 3]

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Please note: the above information is subject to change and we endeavour to keep this website up to date wherever necessary.