Mayo Clinic Laboratories > Renal > Renal pathology

REnal pathology

Quickly diagnose rare and complex cases

Mayo Clinic Laboratories is integrated with Mayo Clinic’s anatomic pathology laboratories in the Department of Laboratory Medicine and Pathology. The fusion of our multispecialty pathology team with our comprehensive approach provides an ideal environment to diagnose rare and complex cases, while enabling the flexibility to keep care local.


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Comprehensive results

All results include the following information-based standards for diagnostic evaluation and reporting of non-neoplastic renal disease:

  • Clinical history.
  • Gross description of biopsy specimen.
  • Light microscopy results.
  • Immunofluorescence microscopy results.
  • Electron microscopy results.
  • Diagnostic comments.
  • Additional stains, performed on a case-by-case basis.

The Mayo Clinic difference

Our highly trained laboratory techs have expertise in assessing and potentially reallocating LM and EM fixed tissues, which ensures adequacy of the material required for consultation. Additionally, when samples are submitted with limited or no tissue in the immunofluorescence preservative (Michel’s/Zeus), we can perform IF using a paraffin-based salvage technique. Combined, these techniques help facilitate diagnosis even in cases where a limited biopsy specimen is received.

We provide high-contrast images by using superior quality processing methods to generate samples for EM. This enables detection of abnormalities, such as amyloid fibrils, tubuloreticular inclusions, and subtle substructure in deposits that may not be visible in lower contrast images produced using rapid throughput methodologies.

Each member of our EM team completes a rigorous training process and recertification at specified intervals. This includes training to apply the same methodical approach for examining the four major tissue compartments — glomeruli, tubules, interstitium, and vessels — with increasing magnification. This provides clarity on the kidney structures and the location of abnormalities, such as deposits, providing pathologists a complete picture to secure the diagnosis.

Rapid turnaround times

  • Initial reports of LM and IF findings in most cases are available the day after specimen receipt.
  • EM results are provided as supplemental reports within one to two days of initial reporting.
  • With advanced notice, expedited processing is available for clinically urgent situations (e.g., rapidly progressive glomerulonephritis or acute kidney injury). In such instances, preliminary LM and IF results are available and called to the nephrologist on the day of sample receipt.
  • Weekend case readout when specimens arrive on Friday.
  • Some additional studies may add one to two days to TAT. Results from mass spectrometry, as an addendum, are available in approximately one week.

Beyond the test result

The anatomic pathology laboratories’ eight-member team of renal pathologists collaborates with Mayo Clinic’s Division of Nephrology and Hypertension and holds special interests in non-neoplastic kidney disease. Our pathologists are available to offer support and strive for superior client communication.

  • Mayo Clinic pathologists routinely call the ordering provider directly to report and discuss the kidney biopsy findings. In addition, reports are faxed to clients’ and providers’ offices.
  • Renal biopsy personnel are on call 24 hours a day, 7 days a week, 365 days a year to answer client calls, respond to questions, and process requests for expedited service. To inquire about the status of a biopsy or request rush processing during normal weekday business hours, clients can call Mayo Clinic’s pathology reporting specialists directly at 507-284-5677 or, if after hours or on the weekend, clients can call 1-855-516-8404.

Renal Pathology

To ensure accuracy and provide timely results, Mayo Clinic renal pathologists evaluate all specimens and report findings based on diagnostic standards of the Renal Pathology Society, Banff Conferences, and International Kidney and Monoclonal Gammopathy Research Group.

Standard pathology work-up receives the following testing:

  • Electron microscopy (EM).
  • Hematoxylin and eosin, periodic acid-Schiff, Masson trichrome, and Jones methenamine silver staining for light microscopy (LM).
  • Immunoglobin A, G, and M, lambda, kappa, C1q, C3, albumin, and fibrinogen immunofluorescence (IF).
  • C4d IF staining for all allograft biopsies.
  • Additional stains performed on a case-by-case basis and on complex cases, while enabling flexibility to keep care local.

Key testing


  • Diagnoses kidney disease that lacks definitive diagnosis.
  • Excludes entities of clinical concern within the differential diagnosis.
  • Provides assessment of chronicity and prognosis for patient’s renal function.
  • Aids treatment plan development and monitoring efficacy.

Additional testing

In addition to pathology consultations, we offer a full menu of ancillary test options. Our tests include but are not limited to:

  • IF stains
    • PLA2R
    • THSD7
    • IgG subtypes
    • Alport
  • IHC stains
    • DNAJB9
    • NELL1
    • Hemoglobin
    • Myoglobin
  • Mass spectrometry
    • Amyloid subtyping
    • Fibrillary glomerulonephritis
    • Fibronectin glomerulonephritis
    • Collagenofibrotic glomerulonephritis
  • In-situ hybridization stains
    • BK, JC, and EB virus
    • Kappa/lambda

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