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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 syndrome or lupus erythematosus

 

This test is not useful in patients without demonstrable antinuclear antibodies.

Clinical Information

Sjogren syndrome (SS)A (Ro), SSB (La), ribonucleoprotein (RNP), and Smith (Sm) proteins are autoantigens commonly referred to as extractable nuclear antigens (ENA). Antibodies to ENA are common in patients with connective tissue diseases (systemic rheumatic diseases).

 

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

 

SSB or La is composed of a 48-kD protein combined with RNA species. SSB antibodies are found primarily in patients with Sjogren syndrome or SLE, where they occur with frequencies of approximately 60% and 15%, respectively.(1,2) SSB antibodies occur only infrequently in the absence of SSA antibodies.

 

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

Interpretation

A positive result for SSA (Ro) or SSB (La) antibodies is consistent with connective tissue disease, including Sjogren syndrome, lupus erythematosus (LE), or rheumatoid arthritis.

 

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

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.

Analytic Time

Same day/1 day

Day(s) and Time(s) Performed

Monday through Saturday; 4 p.m.

Clinical Reference

1. Homburger H, Larsen S: Detection of specific antibodies. In: Rich R, Fleisher T, Schwartz B, et al, eds. Clinical Immunology: Principles and Practice. Mosby-Year Book; 1996:2096-2109

2. Kotzin B, West S: Systemic lupus erythematosus. In: Rich R, Fleisher T, Shearer E, et al, eds. Clinical Immunology Principles and Practice. 2nd ed. Mosby-Year Book; 2001:60.1-60.24

3. Rifai N, Horvath AR, Wittwer CT, eds: Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018

Method Name

Multiplex Flow Immunoassay

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 Special Container
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.

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 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
Mayo Clinic Laboratories | Neurology Catalog Additional Information:

mml-Behavioral, mml-Epilepsy, mml-Headache, mml-Movement-Disorders, mml-Demyelinating-Diseases, mml-Neuroimmunology, mml-Neuromuscular, mml-Autonomic, mml-Pediatric, mml-Spinal-Cord, mml-Neuro-ophthalmology