Test ID SSB SS-B/La Antibodies, IgG, Serum
Reporting Name
SS-B/La Ab, IgG, SUseful For
Evaluating patients with signs and symptoms of a connective tissue disease in whom the test for antinuclear antibodies is positive
Testing for SS-B/La antibodies is not useful in patients without demonstrable antinuclear antibodies.
Testing Algorithm
See Connective Tissue Disease Cascade (CTDC) in Special Instructions.
Specimen Type
SerumSpecimen Required
Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Specimen Volume: 0.5 mL
Specimen Minimum Volume
0.35 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum | Refrigerated (preferred) | 21 days | |
Frozen | 21 days |
Special Instructions
Reference Values
<1.0 U (negative)
≥1.0 U (positive)
Reference values apply to all ages.
Day(s) and Time(s) Performed
Monday through Saturday; 4 p.m.
Test Classification
This test has been cleared, approved or is exempt by the U.S. 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.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
SS-B/La is an extractable nuclear antigen (ENA) composed of a 48-kD protein combined with RNA species. SS-B/La antibodies are found primarily in patients with Sjogren syndrome or lupus erythematosus (LE), where they occur with frequencies of approximately 60% and 15%, respectively.(1,2) SS-B/La antibodies occur only infrequently in the absence of SS-A/Ro antibodies.
SS-B/La is 1 of 4 autoantigens commonly referred to as extractable nuclear antigens (ENA). The other ENA are SS-A/Ro, RNP, and Sm (Smith). Each ENA is composed of 1 or more proteins associated with cytoplasmic or small nuclear RNA species (snRNA) ranging in size from 80 to 350 nucleotides. Antibodies to ENA are common in patients with connective tissue diseases (systemic rheumatic diseases) including LE, mixed connective tissue disease, Sjogren syndrome, scleroderma (systemic sclerosis), and polymyositis/dermatomyositis.
See Connective Tissue Disease Cascade (CTDC) in Special Instructions.
Interpretation
A positive result for SS-B/La antibodies is consistent with connective tissue disease, including Sjogren syndrome and lupus erythematosus.
Clinical Reference
1. Homburger H, Larsen S: Detection of specific antibodies. In Clinical Immunology: Principles and Practice. First edition. Edited by R Rich, T Fleisher, B Schwartz, et al. St. Louis, Mosby-Year Book, 1996, pp 2096-2109
2. Kotzin B, West S: Systemic lupus erythematosus. In Clinical Immunology Principles and Practice. Second edition. Edited by R Rich, T Fleisher, W Shearer, et al. St. Louis, Mosby-Year Book, 2001, pp 60.1-60.24
Analytic Time
1 dayMethod Name
Multiplex Flow Immunoassay