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Test ID SSAB SS-A and SS-B Antibodies, IgG, Serum

Reporting Name

SSA/SSB

Useful For

Evaluating patients with signs and symptoms of a connective tissue disease in whom the test for antinuclear antibodies is positive, especially those with signs and symptoms consistent with Sjogren's syndrome or lupus erythematosus

Profile Information

Test ID Reporting Name Available Separately Always Performed
SSA SS-A/Ro Ab, IgG, S Yes Yes
SSB SS-B/La Ab, IgG, S Yes Yes

Testing Algorithm

See Connective Tissue Disease Cascade (CTDC) in Special Instructions.

Specimen Type

Serum


Specimen 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
Serum Refrigerated (preferred) 21 days
  Frozen  21 days

Reference Values

SS-A/Ro ANTIBODIES, IgG

<1.0 U (negative)

≥1.0 U (positive)

Reference values apply to all ages.

 

SS-B/La ANTIBODIES, IgG

<1.0 U (negative)

≥1.0 (positive) 

Reference values apply to all ages.

Day(s) and Time(s) Performed

Monday through Saturday; 4p.m.

Test Classification

This test has been cleared or approved 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 x 2

LOINC Code Information

Test ID Test Order Name Order LOINC Value
SSAB SSA/SSB 87555-9

 

Result ID Test Result Name Result LOINC Value
SSA SS-A/Ro Ab, IgG, S 33610-7
SSB SS-B/La Ab, IgG, S 33613-1

Clinical Information

SS-A/Ro, SS-B/La, RNP, and Sm are autoantigens commonly referred to as extractable nuclear antigens (ENAs). Antibodies to ENAs are common in patients with connective tissue diseases (systemic rheumatic diseases).

 

SS-A/Ro is composed of protein antigens of 52kD and 60 kD combined with cytoplasmic RNA species. SS-A/Ro antibodies occur in patients with several different connective tissue diseases including Sjogren's syndrome, an autoimmune disease that involves primarily the salivary and lachrymal glands (up to 90% of cases); lupus erythematosus (LE) (40%-60% of cases); and rheumatoid arthritis. SS-A/Ro antibodies are associated with childhood LE, neonatal LE, and with congenital heart block in infants born to mothers with LE.(1,2) SS-A/Ro antibodies have also been reported to be associated with features of extraglandular inflammation in patients with LE including vasculitis, purpura, cytopenias, and adenopathy.

 

SS-B/La is composed of a 48-kD protein combined with RNA species. SS-B/La antibodies are found primarily in patients with Sjogren's syndrome or 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.

 

See Connective Tissue Disease Cascade (CTDC) in Special Instructions and Optimized Laboratory Testing for Connective Tissue Diseases in Primary Care: The Mayo Connective Tissue Diseases Cascade in Publications.

Interpretation

A positive result for SS-A/Ro or SS-B/La antibodies is consistent with connective tissue disease, including Sjogren's syndrome, lupus erythematosus (LE), or rheumatoid arthritis.

 

A positive result for SS-A/Ro antibodies in a woman with LE prior to delivery indicates an increased risk of congenital heart block in the neonate.

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

Same day/1 day

Method Name

Multiplex Flow Immunoassay