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HelpTest Code LAB9798 AB2GP Beta-2 Glycoprotein 1 Antibodies, IgA, Serum
Useful For
Evaluating patients with suspected antiphospholipid syndrome by identification of beta-2 glycoprotein 1 IgA antibodies
Evaluating patients at-risk for antiphospholipid syndrome (APS) who are negative for criteria APS tests
Estimating the risk of thrombosis and/or pregnancy-related morbidity in patients with systemic lupus erythematosus
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
SerumSpecimen Required
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
Specimen Minimum Volume
0.4 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 21 days | |
| Frozen | 21 days |
Reference Values
<15.0 SAU (negative)
15.0-39.9 SAU (weakly positive)
40.0-79.9 SAU (positive)
≥80.0 SAU (strongly positive)
Results are reported in standard IgA anti-beta 2 glycoprotein 1 units (SAU).
Reference values apply to all ages.
Day(s) Performed
Monday, Wednesday, Friday
CPT Code Information
86146
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| AB2GP | Beta 2 GP1 Ab IgA, S | 44447-1 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| AB2GP | Beta 2 GP1 Ab IgA, S | 44447-1 |
Interpretation
The presence of anti-beta-2 glycoprotein 1 (anti-B2GPI) IgA antibodies may be associated with a diagnosis of antiphospholipid syndrome (APS) or systemic lupus erythematosus (SLE). In the absence of "criteria" aPL antibodies for APS and diagnostic tests for SLE, isolated anti-B2GPI IgA must be interpreted with a high degree of caution.
Documentation of persistence for anti-B2GPI IgA, as is the case for criteria B2GPI IgG and IgM antibodies, would be consistent with best clinical practice.
Detection of B2GPI antibodies is not affected by anticoagulant treatment.
Method Description
Purified beta-2 glycoprotein 1 (B2GPI) antigen is bound to the wells of a polystyrene microwell plate under conditions that preserve the antigen in its native state. Prediluted controls and diluted patient sera are added to separate wells, allowing any B2GPIIgA antibodies present to bind to the immobilized antigen. Unbound sample is washed away, and an enzyme-labeled antihuman IgA conjugate is added to each well. A second incubation allows the enzyme-labeled antihuman IgA to bind to any patient antibodies that have attached to the microwells. After washing away any unbound enzyme-labeled antihuman IgA, the remaining enzyme activity is measured by adding a chromogenic substrate and measuring the intensity of the color that develops. The assay can be evaluated spectrophotometrically by measuring and comparing the color intensity that develops in the patient wells with that of a 5-point calibration curve. Semiquantitative results are reported in standard IgA anti-B2GPIunits (SAU).(Package insert: QUANTA Lite beta 2 GP1 IgA ELISA. Inova Diagnostics; Revision 11, 04/2020)
Report Available
4 to 6 daysSpecimen Retention Time
14 daysReject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | OK |
| Heat-treated specimen | Reject |
Method Name
Enzyme-Linked Immunosorbent Assay (ELISA)