From the Guidelines
The initial workup for a patient presenting with nephrotic syndrome should include a comprehensive evaluation to determine the underlying cause and assess disease severity, as recommended by the most recent guidelines 1. The workup should begin with a thorough history and physical examination, followed by laboratory tests including:
- Urinalysis with microscopy
- Urine protein-to-creatinine ratio
- Serum albumin
- Lipid panel
- Complete blood count
- Comprehensive metabolic panel
- Serum creatinine to assess kidney function A 24-hour urine collection for protein quantification is essential to confirm nephrotic-range proteinuria (>3.5g/24h) 1. Serologic testing should include:
- Hepatitis B and C serology
- HIV testing
- Antinuclear antibody
- Complement levels (C3, C4)
- Anti-double stranded DNA
- Serum and urine protein electrophoresis to evaluate for monoclonal gammopathies Blood glucose or hemoglobin A1c should be checked to screen for diabetes. A kidney biopsy is often necessary, particularly in adults, to determine the specific histological pattern and guide treatment decisions, as outlined in the 2021 KDIGO guideline for the management of glomerular diseases 1. Imaging studies such as renal ultrasound may be performed to assess kidney size and rule out obstruction. This comprehensive workup allows for identification of primary renal diseases versus secondary causes of nephrotic syndrome, which is crucial for developing an appropriate treatment plan targeting the underlying etiology. The most recent and highest quality study, the 2021 KDIGO guideline, provides the framework for this approach 1.
From the Research
Initial Workup for Nephrotic Syndrome
The initial workup for a patient presenting with nephrotic syndrome includes:
- Documentation of proteinuria through quantitative measurement, such as urine protein: creatinine ratio (PCR) or albumin: creatinine ratio (ACR) 2
- Assessment of hypoalbuminemia, with a serum albumin level of less than 30 g/L 2
- Evaluation for hyperlipidemia and other complications, such as thromboembolism and infection 2, 3, 4
- Patient history and physical examination to identify potential secondary causes, such as diabetes mellitus, systemic lupus erythematosus, or amyloidosis 2, 4, 5
Diagnostic Tests
Diagnostic tests that may be ordered as part of the initial workup include:
- Urine tests, such as PCR or ACR, to quantify proteinuria 2, 6
- Serum tests, such as albumin and lipid levels, to assess hypoalbuminemia and hyperlipidemia 2, 6
- Renal biopsy, which may be recommended to establish the underlying cause of nephrotic syndrome, particularly in adults or in cases where the diagnosis is uncertain 2, 4, 5
- Genetic testing, which may be considered in children who do not respond to steroid treatment 5
Referral to a Nephrologist
Referral to a nephrologist is often necessary, particularly in cases where the diagnosis is uncertain or where the patient requires specialized care 2, 4, 5. The nephrologist can help to establish the underlying cause of nephrotic syndrome and develop a treatment plan to manage the condition and prevent complications.