Urine protein

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Most proteins are usually retained in the circulation and are not filtered through the glomerulus into the urine, however in dog urine concentraof protein of 0.5 gA are normal. Most of this protein (which is mainly albumin) originates from the kidney itself and the lower urinary tract and has not been filtered through the glomeruli. Care is needed in interpreting protein concentrations in urine because this can be affected by the dilution effects of polyuria.

Test strips are commonly used in veterinary practice and these are more sensitive to albumin than to other proteins. A more useful measure is 24-hour urinary protein loss but this requires collection of all voided urine over a 24 hour period which is not practical without access to a metabolism

cage. Normal urine protein loss can be up to 30 mg/kg body weight per day.

Excessive concentrations of protein in urine (above 10 g/l) are the result of renal disease (various types - but mainly chronic renal failure or glomerular disease), inflammatory disease, hyperproteinaemia (renal threshold is 100 g/l plasma protein), haemorrhage, haemaglobinaemia or myoglobinaemia.