Specimen type:  

Serum

Collection container:  

Gold serum separator (SST) tube

Volume:  

1.0 mL

Minimum volume:  

0.5 mL

Collection instructions:  

Immediately following collection, mix sample by gently inverting 5 times

Processing instructions:  

1. Allow sample to clot for a minimum of 30 minutes
2. Spin 

Transport container:  

Gold serum separator (SST) tube

Alternate collection container:  

Red serum vial/tube, 5 mL

Alternate collection instructions:  

Immediately following collection, mix sample by gently inverting 5 times

Alternate processing instructions:  

1. Allow sample to clot
2. Spin
3. Transfer the serum to a Screw cap transfer vial/tube (Mayo T914), labelled as serum
4. Refrigerate

Alternate transport container:  

Screw cap transfer vial/tube (Mayo T914)

Transport and stability:  

Refrigerated (preferred) - 14 days

Ambient - 8 hours

Frozen - 14 days

Reason for rejection:  

Gross hemolysis

Performing lab:  

Mayo Clinic Laboratories (THSD7): R-NX

Days set up:  

Tu

TAT:  

3 - 7 days

Method:  

Indirect Immunofluorescence Assay (IFA)

Reference ranges:  

Negative

Clinical information:  

Recently, autoantibodies against phospholipase A2 receptor (PLA2R) in the kidney were determined to be the major target antigen for patients with idiopathic/primary membranous nephropathy (MN). Approximately 70% of patients with primary MN circulate anti-PLA2R antibodies, and in the remaining 30% (who are PLA2R-negative), anti-thrombospondin type-1 domain-containing 7A (THSD7A) was shown to have approximately a 10% prevalence (or about 3% of all primary MN patients). Mouse podocytes express THSD7A and introduction of anti-THSD7A autoantibodies induces MN in murine models. Mouse podocytes do not express PLA2R so exogenous administration of anti-PLA2R does not recapitulate membranous nephropathy in mice. Additionally, THSD7A has been described as a potential tumor antigen and, thus, it has been suggested that THSD7A-positive patients merit a thorough cancer screening.

Cautions:  

This test should not be used as a stand-alone test but as an adjunct to other clinical information. A diagnosis of primary or secondary membranous nephropathy (MN) should not be made based on a single test result. The clinical symptoms, results on physical examination, and laboratory tests (eg, serological tests), when appropriate, should always be taken into account when considering the diagnosis of primary versus secondary MN.
Absence of circulating autoantibodies does not rule out a diagnosis of primary MN.

CPT codes:  

86255

Date created:  

06/13/2023

Review date:  

06/14/2023