Laboratory Tests for Glomerulonephropathy Workup
A comprehensive glomerulonephropathy workup requires specific laboratory tests including serum creatinine, estimated GFR, urinalysis with microscopy, 24-hour urine protein collection, and targeted serologic testing based on clinical presentation.
Initial Laboratory Assessment
- Serum creatinine and blood urea nitrogen (BUN) to assess kidney function and establish baseline renal status 1
- Estimated glomerular filtration rate (eGFR) using creatinine-based equations (CKD-EPI preferred) to quantify kidney function 1
- Complete urinalysis with microscopy to evaluate for hematuria, proteinuria, red blood cell casts, and dysmorphic red blood cells which suggest glomerular disease 1
- Urine protein quantification via 24-hour urine collection for total protein and protein electrophoresis, or protein-to-creatinine ratio (PCR) from a first morning sample 1
- Albumin-to-creatinine ratio (ACR) to assess for albuminuria, particularly important in early detection of glomerular disease 1
Serologic Testing
- Complete blood count (CBC) to evaluate for anemia, thrombocytopenia, or leukocytosis 1, 2
- Comprehensive metabolic panel including electrolytes, acid-base status, and liver function tests 1
- Serum albumin to assess for hypoalbuminemia, which may indicate nephrotic syndrome 3
- Lipid profile (cholesterol, triglycerides) as hyperlipidemia is often associated with nephrotic syndrome 3
Immunologic and Specialized Testing
- Antinuclear antibody (ANA) and anti-double-stranded DNA (anti-dsDNA) for lupus nephritis 1
- Complement levels (C3, C4) to evaluate for hypocomplementemic glomerulonephritis 1
- Anti-neutrophil cytoplasmic antibodies (ANCA) for ANCA-associated vasculitis 1
- Anti-glomerular basement membrane (anti-GBM) antibodies for Goodpasture's syndrome 1
- Anti-phospholipase A2 receptor antibodies (anti-PLA2R) for primary membranous nephropathy 1
- Serum and urine protein electrophoresis with immunofixation to detect monoclonal proteins 1
- Serum free light chain assay to evaluate for monoclonal gammopathy of renal significance (MGRS) 1
Additional Testing Based on Clinical Presentation
- Hepatitis B, C, and HIV serologies for infection-associated glomerulonephritis 1
- Blood cultures if infection-related glomerulonephritis is suspected 2
- Cryoglobulins for cryoglobulinemic glomerulonephritis 1
- Anti-streptolysin O (ASO) titers if post-streptococcal glomerulonephritis is suspected 1
- Genetic testing (APOL1, COL4A3, COL4A4, COL4A5) for hereditary forms of glomerulonephritis 1
Kidney Biopsy Considerations
- Kidney biopsy remains the gold standard for definitive diagnosis of glomerulonephropathy and should be considered when 1:
- Nephrotic-range proteinuria (>3.5g/24h) is present
- Rapid decline in kidney function occurs
- Hematuria with proteinuria and/or reduced eGFR is present
- Albumin-to-creatinine ratio >30mg/mmol
- Diagnosis remains unclear after initial workup
Common Pitfalls to Avoid
- Relying solely on dipstick urinalysis without microscopic examination can miss important findings such as dysmorphic RBCs and cellular casts 4
- Using random "spot" urine collections for protein quantification instead of first morning or 24-hour collections 1
- Overlooking monoclonal gammopathies in older adults with unexplained proteinuria or kidney dysfunction 1
- Failing to repeat abnormal tests to confirm persistence of findings before invasive procedures 1
- Neglecting family history which may suggest hereditary forms of glomerulonephritis 1