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Test ID: ENA LA
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ENA LA
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Anti- La/ SS-B antibodies
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Useful For
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When the test for antinuclear antibodies (ANA) is positive, clinical diagnosis of patients with signs and symptoms of a connective tissue disease (CTD) is necessary. Additionally, evaluating the patient for Extractable Nuclear Antigens La (ENA la) can aid in the clinical diagnosis of Sjögren's syndrome and systemic lupus erythematosus (SLE).
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Method name and description
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Method: Fluorescence Enzyme Immunoassay (FEIA), Uses the EliA IgG method on Phadia system.
Using EliA technology solid phase, analyte molecules can be extracted from a sample. To achieve this, a well is coated with an antigen that specifically binds to target antibodies. Following the removal of non-bound antibodies, enzyme-labeled antibodies against human antibodies (EliA IgG Conjugate) are added to form an antibody conjugate complex. This complex is then incubated and non-bound conjugate is subsequently washed away. The bound complex is then incubated with a Development Solution, and after stopping the reaction, the fluorescence in the reaction mixture is measured. A higher response value indicates the presence of a more specific antibody in the specimen.
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Reporting name
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Anti- La/ SS-B antibodies
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Clinical information
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SS-B/La antibodies are the serological hallmark of Sjögren's syndrome but a small proportion of patients remains anti-SS-B/La negative. Reported in 6-15 % of sera from SLE patients, SS-B/La antibodies are associated with a lower prevalence of dsDNA antibodies and renal disease in these patients. Although a strong association of neonatal lupus erythematosus (NLE) with anti-SS-A/Ro was recognized first, the majority of mothers with babies with NLE are now known to have serum SS-B/La antibodies as well.
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Aliases
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Anti-SSB (Anti-Sjogren's Syndrome B)
ENA La
ENA SSB/La
Anti-La
Autoantibodies to SSB (La)
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Specimen type / Specimen volume / Specimen container
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Specimen type: Serum sample.
Specimen Volume: At minimum 2 mL whole blood or 0.5 mL serum.
Container Tube: Plan tube /Serum gel (Yellow top tubes).
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Storage and transport instructions
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For sample transportation, the sample should remain at room temperature (18-25°C ) for no longer than eight hours.
Separated serum samples can be stored at 2-8°C for one week.
Separated serum samples should be frozen at below -20°C for any long-term storage.
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Specimen Rejection Criteria
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Quantity not sufficient (QNS)
Hemolysis
Lipemic
Wrong collection container
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Biological reference intervals and clinical decision values
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Anti-ENA SSB-La antibodies:
| Interpretation of Test Results |
Reference Values (U/ml) |
| Negative |
< 7 |
| Equivocal |
7 - 10 |
| Positive |
> 10 |
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Turnaround time / Days and times test performed / Specimen retention time
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Turnaround Time: 5 working days.
Days and Times test performed: Twice per week starting from Sunday through Thursday from 7:00 to 15:00.
Specimen retention time: Approximately 7 days.
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