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Epic Code LAB724 Glomerular Basement Membrane Antibodies, IgG, Serum

Additional Codes

Mayo Code: GBM

Epic Code: LAB 724

Interface Order Alias: 10087

Cerner: 8606

Reporting Name

Glomerular Basement Membrane IgG Ab

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Clinical Information

Antibodies to glomerular basement membrane (GBM) antigens cause glomerulonephritis, Goodpasture syndrome (glomerulonephritis, often with rapid onset renal failure, and pulmonary hemorrhage), and, less commonly, pulmonary hemosiderosis.(1) Nephrogenic GBM antigens are associated with the noncollagenous carboxyl extension of type IV procollagen. The immunologic stimuli that elicit production of GBM antibodies are not known. There is some evidence of a genetic association with HLA-DR2.

 

GBM antibody-mediated glomerulonephritis and Goodpasture syndrome occur with a bimodal age distribution primarily in males ages 20 to 40 and in patients older than age 50. Glomerulonephritis without pulmonary involvement is more common in the older age group, and shows a female predominance.

Useful For

Evaluating patients with rapid onset renal failure or pulmonary hemorrhage, as an aid in the diagnosis of Goodpasture syndrome

Specimen Type

Serum


Ordering Guidance


If patient is being evaluated for autoimmune skin disease, order CIFS / Cutaneous Immunofluorescence Antibodies (IgG), Serum for evaluation of anti-intercellular substance (ICS) and antibasement membrane zone (BMZ) antibodies.



Specimen Required


Container/Tube: 

Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL


Laboratory Test Directory Note:

COLLECTION NOTE: Volumes listed are in serum or plasma, draw approximately 2 1/2 times the requested volume in whole blood.

Specimen Minimum Volume

0.35 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 21 days
  Frozen  21 days

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus OK

Day(s) Performed

Monday through Friday

Reference Values

<1.0 U (negative)                     

≥1.0 U (positive)

Reference values apply to all ages.

Interpretation

Positive results are consistent with Goodpasture syndrome. Glomerular basement membrane antibodies detected by immunoassay have been reported to be highly specific for Goodpasture syndrome. The sensitivity of this test approaches 87% in untreated patients with systemic disease.(1)

Cautions

A positive test for glomerular basement membrane (GBM) antibodies cannot be relied upon exclusively to establish the diagnosis of a disease mediated by GBM antibodies. Weakly-positive test results may occur in other immune-mediated diseases, and renal or lung biopsy is often required to establish the diagnosis.

 

If patient is being evaluated for autoimmune skin disease, order CIFS / Cutaneous Immunofluorescence Antibodies (IgG), Serum for evaluation of anti-intercellular substance (ICS) and antibasement membrane zone (BMZ) antibodies.

Clinical Reference

1. Pusey CD: Anti-glomerular basement membrane disease. Kidney Int 2003;64:1535-1550

Method Name

Multiplex Flow Immunoassay

Method Description

Glomerular basement membrane (GBM) antigen is covalently coupled to polystyrene microspheres that are impregnated with fluorescent dyes to create a unique fluorescent signature. GBM antibodies, if present in diluted serum, bind to the GBM antigen on the microspheres. The microspheres are washed to remove extraneous serum proteins. Phycoerythrin (PE)-conjugated antihuman-IgG antibody is then added to detect IgG anti-GBM bound to the microspheres. The microspheres are washed to remove unbound conjugate, and bound conjugate is detected by laser photometry. A primary laser reveals the fluorescent signature of each microsphere to distinguish it from microspheres that are labeled with other antigens. A secondary laser reveals the level of PE fluorescence associated with each microsphere. Results are calculated by comparing the median fluorescence response for GBM microspheres to a 4-point calibration curve.(Package insert: Bio-Plex 2200 Vasculitis. Bio-Rad Laboratories, Hercules, CA 4/2012)

Report Available

Same day/1 to 3 days

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

83516

LOINC Code Information

Test ID Test Order Name Order LOINC Value
GBM Glomerular Basement Membrane IgG Ab 31254-6

 

Result ID Test Result Name Result LOINC Value
GBM Glomerular Basement Membrane IgG Ab 31254-6

Forms

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