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HelpEpic Code LAB12309893 Thrombospondin Type-1 Domain-Containing 7A Antibodies, Serum
Additional Codes
Mayo Code: THSD7
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Useful For
Distinguishing primary from secondary membranous nephropathy cases with antibodies against THSD7A
Specimen Type
SerumSpecimen Required
Supplies: Sarstedt 5 mL Aliquot Tube (T914)
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container: Plastic vial
Specimen Volume: 1 mL
Collection Information: Centrifuge and aliquot serum into plastic vial within 2 hours of collection.
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 14 days | |
| Frozen | 14 days | ||
| Ambient | 8 hours |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
Day(s) Performed
Tuesday
Reference Values
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).(1) 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).(2) 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.(3) 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.(4)
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.
Interpretation
Therapy outcome can be monitored by measuring the antibody titer. A titer increase, decrease, or disappearance generally precedes a change in clinical status. Thus, the determination of the antibody titer has a high predictive value with respect to clinical remission, relapse, or risk assessment after kidney transplantation.
Reporting Name
THSD7A Ab, SMethod Name
Indirect Immunofluorescence Assay (IFA)
Method Description
Diluted patient samples are incubated with combinations of substrates. If the reaction is positive, specific antibodies of classes IgA, IgG, and IgM attach to the antigens. In a second step, the attached antibodies are stained with fluorescein-labelled antihuman antibodies and made visible with a fluorescence microscope.(Package insert: Anti-THSD7A IIFT EUROPattern, EUROIMMUN US;V 06/11/2019)
CPT Code Information
86255
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| THSD7 | THSD7A Ab, S | 93339-0 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| THSD7 | THSD7A Ab, S | 93339-0 |
Report Available
3 to 7 daysTest 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.Clinical Reference
1. Beck LH Jr, Bonegio RG, Lambeau G, et al: M-type phospholipase A2 receptor as target antigen in idiopathic membranous nephropathy. N Engl J Med. 2009;361:11-21. doi: 10.1056/NEJMoa0810457
2. Tomas NM, Beck LH Jr, Meyer-Schwesinger C, et al: Thrombospondin type-1 domain-containing 7A in idiopathic membranous nephropathy. N Engl J Med. 2014;371:2277-2287.doi: 10.1056/NEJMoa1409354
3. Tomas NM, Hoxha E, Reinicke AT, et al: Autoantibodies against thrombospondin type 1 domain-containing 7A induce membranous nephropathy. J Clin Invest. 2016;126(7):2519-2532. doi: 10.1172/JCI85265
4. Stahl PR, Hoxha E, Wiech T, Schroder C, Simon R, Stahl RA: THSD7A expression in human cancer. Genes Chromosomes Cancer. 2017;56:314-327. doi: 10.1002/gcc.22440
Forms
If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.