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Test Code MSFGN Fibrillary Glomerulonephritis Confirmation, Mass Spectrometry, Paraffin Tissue

Reporting Name

Fibrillary GN Confirm, LC MS/MS

Useful For

Diagnosing fibrillary glomerulonephritis

Testing Algorithm

A pathology consultation is typically not required. If the results of this test do not support the clinical findings, PATHC / Pathology Consultation may be added if appropriate, upon client approval.

Method Name

Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

AMYLOID


Necessary Information


1. Preliminary pathology report and history are required.

2. A brief explanatory note, or consultative letter, is recommended.



Specimen Required


Supplies: Pathology Packaging Kit (T554)

Specimen Type: Formalin-fixed or B5-fixed, paraffin-embedded tissue block

Collection Instructions:

1. Do not send fixed tissue slides. Testing can only be done on paraffin-embedded tissue blocks.

2. Attach the green pathology address label included in the kit to the outside of the transport container.


Specimen Stability Information

Specimen Type Temperature Time Special Container
AMYLOID Ambient (preferred)
  Refrigerated 

Reject Due To

Fixed tissue slides
wet or frozen tissue
Cytological smears
Nonformalin fixed tissue
Nonparaffin embedded tissue		 Reject

Day(s) Performed

Monday through Friday

CPT Code Information

82542

88380

LOINC Code Information

Test ID Test Order Name Order LOINC Value
MSFGN Fibrillary GN Confirm, LC MS/MS In Process

 

Result ID Test Result Name Result LOINC Value
BA0389 Interpretation 59465-5
BA0390 Participated in the Interpretation No LOINC Needed
BA0391 Report electronically signed by 19139-5
BA0392 Material Received 81178-6
BA0393 Disclaimer 62364-5
BA0394 Case Number 80398-1

Secondary ID

620248

Clinical Information

Fibrillary glomerulonephritis (FGN) is a rare kidney disease with fibrillary deposits in the glomeruli that contain polyclonal IgG and complement, indicating immune complex deposition. Although usually Congo-red negative, recently cases with weak Congo-red positivity have been observed, making the distinction from amyloid more challenging. Liquid chromatography tandem mass spectrometry (LC-MS/MS) performed on microdissected glomeruli from patients with FGN demonstrates a unique proteomic profile including the protein DNAJB9 (Mayo Clinic unpublished observations). The presence of DNAJB9 was found to be highly sensitive and specific for FGN, distinguishing it from other glomerular diseases, including amyloid, immunotactoid glomerulopathy, and immune complex-mediated proliferative glomerulonephritis. The presence of DNAJB9, in the appropriate clinical and pathological context, can be useful to establish a diagnosis of FGN.

Interpretation

An interpretation will be provided.

Cautions

No significant cautionary statements

Clinical Reference

1. Said SM, Sethi S, Valeri AM, et al. Renal amyloidosis: origin and clinicopathologic correlations of 474 recent cases. Clin J Am Soc Nephrol. 2013;8(9):1515-1523

2. Vrana JA, Gamez JD, Madden BJ, Theis JD, Bergen HR 3rd, Dogan A. Classification of amyloidosis by laser microdissection and mass spectrometry-based proteomic analysis in clinical biopsy specimens. Blood. 2009;114(24):4957-4959

3. Rosenstock JL, Markowitz GS, Valeri AM, Sacchi G, Appel GB, D'Agati VD. Fibrillary and immunotactoid glomerulonephritis: Distinct entities with different clinical and pathologic features. Kidney Int. 2003;63(4):1450-1461

4. Casanova S, Donini U, Zucchelli P, Mazzucco G, Monga G, Linke RP. Immunohistochemical distinction between amyloidosis and fibrillar glomerulopathy. Am J Clin Pathol. 1992;97(6):787-795

5. Rosenmann E, Eliakim M. Nephrotic syndrome associated with amyloid-like glomerular deposits. Nephron. 1977;18(5):301-308

6. Nasr SH, Vrana JA, Dasari S, et al. DNAJB9 is a specific immunohistochemical marker for fibrillary glomerulonephritis. Kidney Int Rep. 2017;3(1):56-64

7. Dasari S, Alexander MP, Vrana JA, et al. DnaJ Heat Shock Protein Family B Member 9 is a Novel Biomarker for Fibrillary GN. J Am Soc Nephrol. 2018;29(1):51-56

Method Description

Affected areas are removed from paraffin-embedded tissues by laser microdissection. Protein digestion is performed, followed by liquid chromatography tandem mass spectrometry.(Unpublished Mayo method)

Report Available

7 to 15 days

Specimen Retention Time

Until reported

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

Forms

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