Providing answers
to guide treatment

Diagnose complex cases

Mayo Clinic Laboratories is integrated with the anatomic pathology laboratories in the Department of Laboratory Medicine and Pathology at Mayo Clinic. 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.

Learn more about how to order these evaluations at your institution.

By The Numbers


analyzed biopsies and delivered answers per year in our Renal Biopsy Laboratory


Mayo Clinic renal biopsy technicians and renal pathologists available for STAT diagnosis


specialty stains and ancillary tests available

Optimal interpretation for actionable answers

To ensure accuracy and provide timely results, Mayo Clinic renal pathologists evaluate all specimens and report findings based on diagnostic standards published by 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

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

Definitive diagnosis

RPCWT | Renal Pathology Consultation, Wet Tissue

Clinical Utility

  • Diagnose kidney disease that lacks definitive diagnosis
  • Exclude entities of clinical concern within the differential diagnosis
  • Provide assessment of chronicity and prognosis for patient’s renal function
  • Aid treatment plan development and monitoring efficacy

Precision analysis stems from proper specimen collection

To increase accuracy and improve turnaround time, refer to the renal biopsy patient information and renal biopsy procedure for handling tissue on the LM IF and EM forms.

Innovating at the speed of discovery

Mayo Clinic pathologists continue to advance the field of renal pathology testing and improve how clinicians care for patients through ongoing research. Recent testing innovations include discovering the DNAJB9 biomarker for fibrillary glomerulonephritis; and the NELL-1, exostosin 1/2, protocadherin PCDH7, and semaphorin 3B biomarkers for membranous nephropathy. In addition, we’ve developed a tissue-based assay for utilizing immunoglobulin heavy-light chain antibodies in the diagnosis of monoclonal gammopathy-related glomerulonephritis.

The Mayo Clinic difference

Our highly trained laboratory techs have expertise 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 (TAT)

  • 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 (i.e., 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.

Comprehensive ancillary 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
  • In-situ hybridization stains
    • BK, JC, and EB virus
    • Kappa/lambda
  • IHC stains
    • DNAJB9
    • NELL1
    • Hemoglobin
    • Myoglobin
  • Mass spectrometry
    • Amyloid subtyping
    • Fibrillary glomerulonephritis
    • Fibronectin glomerulonephritis
    • Collagenofibrotic glomerulonephritis

For a complete list of renal pathology testing, please utilize the test requisition form. For a complete list of immunohistochemical in situ hybridization tests, please utilize the ISH/IHC form.

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.

Learn more about how to order these evaluations at your institution.