This video demonstrates the critical and specialized protocol for processing a fresh kidney transplant biopsy to ensure optimal quality across multiple diagnostic modalities. The primary concern is the rapid degradation of fresh tissue, requiring immediate division and fixation. The protocol involves separating the core samples into three portions: minute tips for Electron Microscopy (EM) fixed in Glutaraldehyde; the middle sections for Light Microscopy (LM), which must be wrapped carefully in lens paper (not sponges or bags) to prevent distortion; and the remaining tissue for Immunofluorescence (IF) fixed in Michel's solution. The speaker emphasizes consulting the attending physician if the core quality is poor and warns against delays in fixation.
Summarizing the Fresh Kidney Biopsy Handling Protocol
0:09 Handling Importance: Fresh kidney biopsies must be divided and placed in fixatives quickly to prevent degradation, which could necessitate a painful repeat procedure for the patient.
0:29 Consultation Protocol: If the biopsy core quality is poor or fragmented, always consult the attending physician before processing.
0:50 Fresh Specimen Warning: Any specimen received fresh requires specialized handling. Do not use standard cassettes, bags, or sponges, as they will distort the fresh tissue (3:16).
1:36 Step 1: Electron Microscopy (EM): The "super tiny" tips of the core (aiming for glomeruli) are submitted for EM.
Key Detail: These tips are placed in Glutaraldehyde. Ensure a sufficient amount of Glutaraldehyde is used, as it penetrates tissue much slower than formalin (2:25).
3:13 Step 2: Light Microscopy (LM): The remaining smaller cores are prepared for light microscopy using lens paper.
Key Detail: Lens paper is folded with overlapping corners (creating "bunny ears") rather than matched corners. This technique allows the embedder to easily open the paper without losing the fragile fresh sample (4:04).
Submission: The wrapped sample is placed in a cassette.
4:33 Step 3: Immunofluorescence (IF): The largest remaining piece of the core is submitted for IF.
Fixation: Place the tissue in the original, labeled container and add Michel's fixative.
5:16 Key Takeaway: Do not allow the fresh biopsy to sit in saline for too long, as it will quickly degrade. Timely fixation is critical for quality.