Module 1 · Visual Grammar
Systematic Kidney Biopsy Approach
Every biopsy is read in the same fixed sequence. Do not skip ahead. The sequence is the reasoning.
- 01
Low-power survey
Scan the entire specimen at low magnification before zooming in. Note overall architecture, cortex vs medulla, distribution of injury (focal/diffuse, segmental/global), and any obvious mass lesions or scarring.
- 02
Biopsy adequacy
Confirm cortex is present and count glomeruli. Note tissue allocation across LM, IF, and EM. An inadequate biopsy limits every downstream interpretation.
- 03
Compartment identification
Decide which compartment — glomerular, tubular, interstitial, or vascular — carries the dominant abnormality. Many diseases involve more than one; name the primary and secondary compartments.
- 04
Stain and modality recognition
Identify what you are looking at: H&E, PAS, Jones silver, trichrome, IF, or EM. Each modality answers a different question. Do not ask a stain a question it cannot answer.
- 05
Pattern of injury
Describe the tissue reaction: hypercellularity, capillary wall thickening, sclerosis, crescents, necrosis, inflammation, fibrosis, thrombi. Name the pattern before naming the disease.
- 06
Active vs chronic lesion assessment
Classify each finding: active lesions may be treatment-responsive; chronic lesions signal irreversible damage. Most biopsies show a mix — quantify both.
- 07
Clinicopathologic correlation
Connect findings to the clinical syndrome: nephrotic, nephritic, RPGN, AKI, CKD, hematuria, proteinuria, or transplant dysfunction. The biopsy is one input to a synthesis, not the whole answer.