Donors at risk: proteinuria

Potential living donors should have their urinary protein excretion measured using either a 24- hour urine collection ( daily excretion) or a spot urine sample ( protein/ creatinine ratio). A urine protein excretion of > 300 mg/ day ( 24 hour collection) or of > 30 mg/ mmol ( spot urine protein/ creatinine ratio) is usually a contraindication to live donation. Further investigations are warranted when urine protein excretion is > 150 mg/day but less than < 300 mg/ day ( corresponds approximately with spot urinary protein/ creatinine of > 15 mg/ mmol but < 30 mg/ mmol). Repeat urinary protein estimation, as well as measurement of urinary albumin excretion may help in further assessing potential living donors. Although overt proteinuria may be absent, the presence of microalbuminuria ( urinary albumin excretion of > 30 mg/ day or > 20 mg/ min; albumin/ creatinine ratio > 2.5 mg/ mmol) should be considered a relative contraindication to live donation. Microalbuminuria or mild proteinuria (< 300 mg/ day) occurring in the presence of another associated clinical or laboratory abnormality ( e. g. hypertension, obesity, glucose intolerance, glomerular haematuria) should be considered a relative contraindication to live donation. In potential living donors with minor degrees of proteinuria or albuminuria, a renal biopsy may help in further assessing the donor's risk of developing progressive renal disease following donation ( Opinion). Donors should have their urinary protein excretion measured as part of their routine, follow- up care. It is recommended that this be performed at least once a year along with blood pressure and serum creatinine measurement ( Opinion).