Distinguishing primary from secondary membranous nephropathy
Anti-phospholipase A2 receptor (PLA2R) antibodies are highly specific for the diagnosis of primary membranous nephropathy.
As many as 70% to 75% of patients with primary membranous nephropathy are positive for anti-PLA2R.
A titer increase, decrease, or disappearance generally precedes a change in clinical status.
Test Id | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
SCOPE | Phospholipase A2 Receptor IFA, S | No | Yes |
EURO | Phospholipase A2 Receptor ELISA, S | No | Yes |
EURO: Enzyme-Linked Immunosorbent Assay (ELISA)
SCOPE: Indirect Immunofluorescence Assay (IFA)
PLA2R
Anti-PLA2R
Serum SST
Collection Container/Tube: Serum gel
Specimen Volume: 1 mL
If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.
0.5 mL
Gross hemolysis | Reject |
Gross lipemia | OK |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum SST | Refrigerated (preferred) | 14 days | |
Frozen | 14 days | ||
Ambient | 8 hours |
Distinguishing primary from secondary membranous nephropathy
Membranous nephropathy (MN) is a rare disease in which immune complexes deposit at the glomerular basement membrane, causing damage to the filtration barrier, resulting in proteinuria. Recent studies have shown that in approximately 70% of patients with primary MN (pMN), the immune complexes consist of autoantibodies against the podocyte protein M-type phospholipase A2 receptor (PLA2R).(1) There is also evidence that levels of anti-PLA2R autoantibodies correlate well with disease activity and progression.(2) The presence of anti-PLA2R antibodies could also potentially be used to differentiate pMN from other causes of nephrotic syndrome if a biopsy is not possible. Among patients with chronic kidney disease (CKD) awaiting kidney transplantation, higher levels of anti-PLA2R could predict those more likely to recur after transplantation.(2)
ELISA:
Negative: <14 RU/mL
Borderline: > or =14-<20 RU/mL
Positive: > or =20 RU/mL
IFA: Negative
Therapy outcome can be monitored by measuring the anti-phospholipase A2 receptor (PLA2R) 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.
This test should not be used as a stand-alone test but an adjunct to other clinical information. A diagnosis of primary or secondary membranous nephropathy (MN) should not be made 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 anti-phospholipase A2 receptor (PLA2R) autoantibodies does not rule out a diagnosis of primary MN.
1. Beck L, Bonegio R, Lambeau G, et al: M-type phospholipase A2 receptor as target antigen in idiopathic membranous nephropathy. N Engl J Med 2009;361:11-21
2. Schlumberger W, Hornig N, Lange S, et al: Differential diagnosis of membranous nephropathy with autoantibodies to phospholipase A2 receptor 1. Autoimmun Rev 2014 Feb;13(2)108-113
Enzyme-Linked Immunosorbent Assay (ELISA):
The test kit provides microtiter strips each with 8 break-off reagent wells. In the case of positive samples, specific IgG antibodies (also IgA and IgM) will bind to the antigens. To detect the bound antibodies, a second incubation is carried out using an enzyme-labelled antihuman IgG (enzyme conjugate) catalyzing a color reaction.(Package insert: EUROIMMUN Anti-PLA2R ELISA [IgG] Kit, EUROIMMUN US, Morris Plains, NJ, V 9/23/2014)
Indirect Immunofluorescence Assay (IFA):
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: EUROIMMUN Anti-PLA2R IFA Kit, EUROIMMUN US, Morris Plains, NJ, V 9/23/2014)
Monday, Wednesday, Friday
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.
EURO-83520
SCOPE-86255
Test Id | Test Order Name |
Order LOINC Value
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.
|
---|---|---|
PLA2R | Phospholipase A2 Receptor AB, S | In Process |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
EURO | Phospholipase A2 Receptor ELISA, S | 73737-9 |
SCOPE | Phospholipase A2 Receptor IFA, S | 82991-1 |