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HelpTest Code SSB SS-B/La Antibodies, IgG, Serum
Reporting Name
SS-B/La Ab, IgG, SUseful For
Evaluating patients with clinical features or at-risk for connective tissue disease, especially Sjögren syndrome.
Testing Algorithm
For more information see Connective Tissue Disease Cascade.
Method Name
Multiplex Flow Immunoassay
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
0.35 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 |
| Heat-treated | Reject |
Special Instructions
Reference Values
<1.0 U (negative)
≥1.0 U (positive)
Reference values apply to all ages.
Day(s) Performed
Monday through Saturday
CPT Code Information
86235
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| SSB | SS-B/La Ab, IgG, S | 33613-1 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| SSB | SS-B/La Ab, IgG, S | 33613-1 |
Clinical Information
Sjogren syndrome (SjS) is a heterogeneous systemic autoimmune rheumatic disorder characterized by diverse immunologic responses to SS-A/Ro and SS-B/La antigens.(1) These immune reactivities have been implicated in the destruction of the epithelium of the exocrine glands with the demonstration of typical peri-epithelial lymphocytic infiltration that can vary from sicca syndrome to systemic disease and lymphoma.(2) The SS-A/Ro and SS-B/La system is considered as a heterogeneous antigenic complex which is made up of three different proteins (Ro52, Ro60 and La) and four small RNAs particles.(1,2) The SS-B/La antigen is a 48 kDa phosphorylated protein which can be found in the nucleus and the cytoplasm and binds to several RNA molecules.(3) SS-B/La appears to be susceptible to proteolysis and degrades into smaller but immunoreactive polypeptides.(4)
Unlike antibodies to SS-A/Ro that are present in SjS and other connective tissue diseases (CTD) [systemic lupus erythematosus, systemic sclerosis, inflammatory myopathies, overlap CTD] and primary biliary cholangitis, anti-SS-B/La antibodies are found primarily in patients with SjS.(2,5,6) In addition, SS-A/Ro antibodies may be found alone in many patients with SjS, however, anti-SS-B/La autoantibodies without SS-A/Ro has limited significant association for SjS diagnosis or phenotypic categorization.(2,6,7) Lastly, whereas testing for anti-SS-A/Ro antibodies is included in the 2016 American College of Rheumatology/European League Against Rheumatism classification criteria for primary SjS, evaluation of anti-SS-B/La antibodies is not required.(8)
In a recent multicenter study of more than 10,500 patients with primary SjS, anti-SSB/La antibodies were detected in 58% of anti-SSA/Ro antibody-positive cases.(9) Anti-SS-B/La antibodies are detected using a variety of solid-phase (eg, plate, bead, or membrane) immunoassays such as enzyme-linked immunosorbent assay, fluorometric enzyme-linked immunoassays, chemiluminescence immunoassays, addressable laser bead immunoassay particle-based multianalyte technology and dot or line immunoassays.(10)
For more information see Connective Tissue Disease Cascade.
Interpretation
A positive result for anti-SS-B/La antibodies may be suggestive of a diagnosis of primary or secondary connective tissue disease including Sjogren syndrome if compatible autoantibody profile and clinical symptoms are present. The positive predictive value for primary Sjogren syndrome is increased with positivity for antibodies to Ro52, Ro60, and SS-B/La. Combination of anti-SSB-B/A and anti-Ro52 and/or anti-Ro60 antibodies may also be useful in the phenotypic stratification of patients with primary Sjogren syndrome.
Cautions
Low levels and/or single positivity for anti-SS-B/La antibodies are likely to have limited clinical significance for the diagnosis and phenotypic stratification of patients with primary Sjogren syndrome.
Method Description
Affinity-purified SS-B antigen is coupled covalently to polystyrene microspheres, which are impregnated with fluorescent dyes to create a unique fluorescent signature. SS-B/La antibodies, if present in diluted serum, bind to the SS-B 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-SS-B/La 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, and a secondary laser reveals the level of PE fluorescence associated with each microsphere. Results are calculated by comparing the median fluorescence response for SS-B/La microspheres to a 4-point calibration curve.(Package insert: Bioplex 2200 ANA Screen. Bio-Rad Laboratories; 02/2019)