Urinary Protein Excretion Estimation
Quantifies 24-hour proteinuria with protein/creatinine ratio from a single urine sample.
Avoid using overnight or first morning void as urine sample.
Advice
- UPEE >3.5 g/day in adults is associated with nephrotic syndrome.
- A decrease in protein excretion to <2 g/day, either in response to therapy or spontaneously, is associated with improved long-term prognosis.
- Additional workup for proteinuria should include a serum creatinine, glomerular filtration rate (GFR) estimation, and an examination for urine sediment (e.g., casts, acanthocytes).
Management
- Patients with persistent low-grade proteinuria unrelated to decreased kidney function or a systemic disease typically have no long-term complications, even if untreated.
- Patients with low-grade proteinuria should be evaluated yearly to make sure it is not getting worse and that kidney function is stable.
- Many nephrologists use an antihypertensive drug, such as an angiotensin-converting enzyme (ACE) inhibitor or angiotensin II receptor antagonist (ARB), to reduce or eliminate proteinuria.
- Sodium-glucose cotransporter-2 (SGLT2) inhibitors are recommended for individuals with significant proteinuria, with or without diabetes.
- Renal biopsy may be warranted if (list is not exhaustive):
- UPEE is >3.5 g/day.
- Non-nephrotic range proteinuria with:
- Active urine sediment (e.g., cellular casts, hematuria).
- Reduced GFR.
- Progressing or persistent proteinuria.
- New-onset hypertension.
For additional management recommendations, please refer to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines.