Background: Proteinuria is an indicator of renal disease. Measurement of protein excretion is important for diagnosis and follow-up of renal disease, but measuring 24-hour protein excretion is a cumbersome procedure.
Material and methods: A simplified validated method for measuring excretion is obtained by measuring urine protein/creatinine concentration in a spot urine sample.
Results: We have implemented such ratios for clinical routine measurements of proteinuria at Rikshospitalet University Hospital in Oslo. Whenever protein or albumin in urine is requested, the laboratory also measures urine creatinine and reports the ratio in mg protein/mmol creatinine. 24-hour excretion is approximately 10 times the ratio. The rationale for using the ratio is given and proteinuria pathophysiology and potential risks and treatment options are discussed.
Interpretation: Our experience is that use of the urine protein/creatinine ratio is a significant improvement. Measurements are now routinely made whereas quantification was rarely performed when 24-hour urine samples were used. We recommend that physicians and laboratories implement the use of this ratio in their daily routines.