Test Id : RPCWT

The Renal Pathology Consultation is performed by a Mayo Clinic renal pathologist and entails the performance of appropriate procedures and stains based on the material received, patient information, and specific findings on the case in order to determine a diagnosis. Optimal/standard diagnostic interpretation of a medical kidney biopsy requires integration of the light microscopy, immunofluorescence, and electron microscopy findings together with the clinical and laboratory data for the patient. Published standards by the Renal Pathology Society are followed for the diagnostic evaluation and reporting of non-neoplastic kidney disease.(1)

Light Microscopy:

Wet/unprocessed tissue submitted for light microscopy routinely includes the preparation of stains, which include hematoxylin and eosin, periodic acid Schiff, Masson trichrome, and Jones methenamine silver stains.

Immunofluorescence:

Wet/unprocessed tissue submitted for immunofluorescence may include the following stains to render an accurate diagnosis. These stains include IgA, IgG, IgM, C1q, C3, albumin, fibrinogen, kappa light chain, and lambda light chain stains with C4d added if the biopsy is an allograft.

The IgG subtypes (IgG1, IgG2, IgG3, IgG4) are typically only utilized if the biopsy shows features suspicious for a monoclonal/monotypic deposition process involving IgG.

Alport (collagen IV, alpha 2 and alpha 5) staining is performed in the setting of biopsy findings that are consistent with hereditary nephritis/Alport syndrome.

Phospholipase A2 receptor staining is performed in the setting of membranous nephropathy/glomerulonephritis to aid in determining whether it is most likely primary/idiopathic or secondary.

Paraffin-Based Immunofluorescence Stains:

The paraffin-based immunofluorescence stains listed above would only be utilized in the special circumstance when there is no tissue or inadequate tissue available for standard immunofluorescence or if there are findings that raise concern for so-called "masked deposits."

Electron Microscopy:

Wet/unprocessed tissue submitted for electron microscopy will be processed for transmission electron microscopy. A formal interpretive report is issued, incorporating the findings from all tests performed for diagnostic purposes.

For more information see Pathology Consultation Ordering Algorithm.

This test is for a renal wet tissue consultation only. For a consultation on paraffin embedded renal tissue and slides, order PATHC / Pathology Consultation.

1. Advise shipping specimens in Styrofoam transportation coolers to avoid extreme hot or cold temperatures and to ensure specimens are received at required specimen transport (stability) temperature.

2. Attach the green "Attention Pathology" address label (T498) to the outside of the transport container before putting into the courier mailer.

All requisition and supporting information must be submitted in English.

The following information is required:

1. All requisitions must be labeled with:

-Patient name, date of birth, and medical record number

-Name and phone number of the referring nephrologist/pathologist or ordering provider

-Anatomic site and collection date

2. A brief patient history is essential to achieve a consultation fully relevant to the ordering provider’s needs.

3. Additional information needed:

-Recent nephrology consultation notes

-History and physical progress notes

-Recent laboratory test results, including serologies (eg, renal/kidney function panel, antinuclear antibodies, anti-glomerular basement membrane antibodies, C3/C4, serum or urine protein electrophoresis, serum albumin, hepatitis/HIV screen, urinalysis)

Specimen Type: Kidney biopsy

Supplies: Renal Biopsy Kit (T231)

Specimen Volume: Entire specimen

Collection Instructions: Collect and prepare biopsy specimens per instructions in Renal Biopsy Procedure for Handling Tissue for Light Microscopy, Immunofluorescent Histology, and Electron Microscopy.

Additional Information: On Saturdays and holidays, RUSH (same day as receipt) interpretation is available for clinically emergent cases (eg, acute kidney failure, rapidly progressive glomerulonephritis, acute kidney allograft dysfunction) but requires advanced notification and approval by a Mayo Clinic Renal Pathologist (507-284-5677).

To request RUSH service outside of regular business hours, contact Mayo Clinic Laboratories at 800-533-1710.

1. Information on accessing digital images for renal consult cases can be accessed through this website: https://news.mayocliniclabs.com/pathology/digital-imaging/

2. Clients ordering stains using a manual requisition form will not have access to digital images.

• Renal Biopsy Patient Information
• Renal Biopsy Procedure for Handling Tissue for Light Microscopy, Immunofluorescent Histology, and Electron Microscopy
• Pathology Consultation Ordering Algorithm

1. Renal Biopsy Patient Information

2. If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.

See Specimen Required

Evaluating and managing patients with kidney disease

Following the progression of known kidney disease or response to therapy

Determining the cause of dysfunction in the transplanted kidney (allograft)

The Renal Pathology Consultation is performed by a Mayo Clinic renal pathologist and entails the performance of appropriate procedures and stains based on the material received, patient information, and specific findings on the case in order to determine a diagnosis. Optimal/standard diagnostic interpretation of a medical kidney biopsy requires integration of the light microscopy, immunofluorescence, and electron microscopy findings together with the clinical and laboratory data for the patient. Published standards by the Renal Pathology Society are followed for the diagnostic evaluation and reporting of non-neoplastic kidney disease.(1)

Light Microscopy:

Wet/unprocessed tissue submitted for light microscopy routinely includes the preparation of stains, which include hematoxylin and eosin, periodic acid Schiff, Masson trichrome, and Jones methenamine silver stains.

Immunofluorescence:

Wet/unprocessed tissue submitted for immunofluorescence may include the following stains to render an accurate diagnosis. These stains include IgA, IgG, IgM, C1q, C3, albumin, fibrinogen, kappa light chain, and lambda light chain stains with C4d added if the biopsy is an allograft.

The IgG subtypes (IgG1, IgG2, IgG3, IgG4) are typically only utilized if the biopsy shows features suspicious for a monoclonal/monotypic deposition process involving IgG.

Alport (collagen IV, alpha 2 and alpha 5) staining is performed in the setting of biopsy findings that are consistent with hereditary nephritis/Alport syndrome.

Phospholipase A2 receptor staining is performed in the setting of membranous nephropathy/glomerulonephritis to aid in determining whether it is most likely primary/idiopathic or secondary.

Paraffin-Based Immunofluorescence Stains:

The paraffin-based immunofluorescence stains listed above would only be utilized in the special circumstance when there is no tissue or inadequate tissue available for standard immunofluorescence or if there are findings that raise concern for so-called "masked deposits."

Electron Microscopy:

Wet/unprocessed tissue submitted for electron microscopy will be processed for transmission electron microscopy. A formal interpretive report is issued, incorporating the findings from all tests performed for diagnostic purposes.

For more information see Pathology Consultation Ordering Algorithm.

The Mayo Renal Pathology service is staffed by board-certified pathologists who have a special interest in non-neoplastic diseases of the kidney.

Kidney biopsy has proven to be of value in the clinical evaluation and management of patients with kidney disease, including acute and chronic renal insufficiency, nephrotic syndrome, nephritic syndrome, proteinuria, and hematuria, and in the overall management of kidney transplant recipients.

Optimal interpretation of a kidney biopsy requires integration of clinical and laboratory results with light microscopic, immunofluorescent histology, and electron microscopy findings.

An interpretive report will be provided.

Both a verbal report and a faxed report are provided to nephrologists for Mayo Clinic Laboratories cases.

Digital images for electron microscopy and immunofluorescent stains may be downloaded as needed using the digital imaging link provided in the final report.

In most cases, electron microscopy results are reported as an addendum, and a final report including these findings is issued. This final report is again faxed to the submitting nephrologist and mailed to the submitting pathology laboratory, along with a representative set of the light microscopy slides.

Accurate and timely interpretation of a kidney biopsy requires integration of light microscopic, immunofluorescent histology, and electron microscopic findings with clinical and laboratory data. Failure to provide the relevant clinical history and laboratory results may result in a delay in the interpretation or the inability to adequately correlate the biopsy findings with the clinical picture.

1. Chang A, Gibson IW, Cohen AH, et al. A position paper on standardizing the nonneoplastic kidney biopsy report. Clin J Am Soc Nephrol. 2012;7:1365-1368

2. Jennette JC, D'Agati VD, Olson JL, Silva FG, eds. Heptinstall's Pathology of the Kidney. 7th ed. Lippincott Williams and Wilkins; 2014

Gross and microscopic examination of tissue. Ancillary testing is ordered at the discretion of the Mayo Clinic pathologist. The results of all testing will be provided in the context of the final pathology report.(Unpublished Mayo method)

Monday through Saturday

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Not Applicable

88305 (If appropriate)

88348 (If appropriate)

88313 (If appropriate)

88346 (If appropriate)

88350 (If appropriate)