From the Guidelines
For focal segmental glomerulosclerosis (FSGS), I recommend ordering a comprehensive panel of laboratory tests to evaluate kidney function, identify potential causes, and guide treatment decisions, as outlined in the KDIGO 2021 clinical practice guideline for the management of glomerular diseases 1.
Initial Evaluation
Start with a complete urinalysis with microscopy to assess for proteinuria, hematuria, and cellular casts. Quantify protein excretion with a 24-hour urine collection for protein or a spot urine protein-to-creatinine ratio.
Kidney Function and Electrolytes
Order a comprehensive metabolic panel to evaluate kidney function (BUN, creatinine, eGFR), electrolytes, and albumin levels.
Hematologic Abnormalities
Complete blood count will help identify anemia or other hematologic abnormalities.
Lipid Profile
Lipid profile is important as FSGS often causes hyperlipidemia.
Serologic Tests
Serologic tests should include complement levels (C3, C4), antinuclear antibody (ANA), anti-double-stranded DNA, hepatitis B and C serologies, and HIV testing to rule out secondary causes, as suggested by the 2013 KDOQI US commentary on the 2012 KDIGO clinical practice guideline for glomerulonephritis 1.
Genetic Testing
Consider genetic testing in patients with family history of kidney disease or early-onset FSGS, as recommended in the executive summary of the KDIGO 2021 guideline for the management of glomerular diseases 1. These tests help establish the diagnosis, determine disease severity, identify potential underlying causes, and provide baseline values to monitor treatment response. Regular monitoring of these parameters is essential for managing FSGS effectively and adjusting therapy as needed.
From the Research
Labs to Order for FSGS
To diagnose and manage Focal Segmental Glomerulosclerosis (FSGS), several laboratory tests can be ordered. These include:
- Urinalysis to check for proteinuria and hematuria 2, 3
- Serum creatinine and estimated glomerular filtration rate (eGFR) to assess renal function 2, 4
- Electrolyte panel to evaluate for electrolyte imbalances 5
- Complete blood count (CBC) to rule out anemia and other hematological abnormalities 5
- Liver function tests to assess for liver disease, which can be associated with FSGS 6
- Immunoglobulin levels and complement levels to evaluate for immune-mediated causes of FSGS 3
- Genetic testing for APOL1 risk alleles, which can be associated with FSGS in individuals of African descent 3
- Viral serologies, such as HIV and hepatitis B and C, which can be associated with FSGS 3
Additional Tests
Additional tests that may be ordered include:
- Renal biopsy to confirm the diagnosis of FSGS and assess the extent of disease 2, 3, 5
- Electron microscopy to evaluate for podocyte foot process effacement, which is characteristic of FSGS 3, 5
- Immunofluorescence to rule out other primary glomerulopathies 3
Monitoring
Regular monitoring of patients with FSGS includes: