A kidney biopsy is not routinely performed as soon as nephrotic syndrome is found during lab work-up. According to the National Kidney Foundation (NKF) Kidney Disease – Improve Global Outcomes (KDIGO) guidelines in 2012, an initial attempt using corticosteroids should be performed before a renal biopsy is performed. A renal biopsy of minimal change disease shows no or minimal abnormalities on light microscopy. Lipid-laden cells may be seen in proximal tubular epithelium. Renal biopsy is often unremarkable under immunofluorescence, with the exception of few cases that stain positively for IgM antibodies and C3.The hallmark of minimal change disease is absence of visible alterations on light microscopy and absence of effacement of foot processes by electron microscopy.

• A renal biopsy of minimal change disease shows no or nearly normal with abnormalities on light microscopy.^[1][2][3]
• Mesangial proliferation is seen on light microscopy.
• Lipid-laden cells may be seen in proximal tubular epithelium.
• Additional features of focal segmental glomerulosclerosis, such as mesangial prominence, interstitial fibrosis, and tubular atrophy, or glomerular tip lesions of focal segmental glomerulosclerosis, may be seen in patients who have complicated disease.^[4]
• Those with acute renal injury may have histological features of focal flattening of the proximal tubular epithelium.^[4]

• Renal biopsy is often unremarkable under immunofluorescence, with the exception of few cases that stain positively for IgM antibodies and C3.^[4]