When there is suspected focal segmental glomerulosclerosis (FSGS), what is the next step?

• A. Renal biopsy
• B. Urinalysis
• C. Renal ultrasound
• D. Blood pressure measurement

Answer: (A)

Definitive identification of this glomerular disease relies on tissue diagnosis. When FSGS is suspected, obtaining a renal biopsy provides the histologic confirmation needed to distinguish it from other nephrotic-range diseases and to guide treatment.

A biopsy reveals the hallmark: focal and segmental sclerosis with hyalinosis on light microscopy, and it shows podocyte foot-process effacement on electron microscopy. This precise pattern is what sets FSGS apart from conditions like minimal change disease or membranous nephropathy, which have different treatments and prognoses. Because management choices—such as steroid therapy or other immunosuppressants—depend on the exact pathology, the biopsy is the critical next step.

Urinalysis and blood pressure measurements help characterize the clinical picture and monitor disease, but they don’t confirm the diagnosis. Imaging like renal ultrasound can assess structure or guide biopsy, but it’s not the diagnostic step itself.