Lab Guide
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Test ID: ENA Scl-70
ENA Scl-70
Anti- Scl-70/anti-topoisomerase antibodies
Useful For

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 Scl70 (ENA Scl70) can aid in the clinical diagnosis of scleroderma (diffuse form).

Method name and description

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.

Reporting name

Anti- Scl-70/anti-topoisomerase antibodies

Clinical information

Determining the presence of antinuclear antibodies (ANA) is crucial for clinically diagnosing connective tissue diseases. The presence of antibodies against Scl-70 is specific and characteristic for scleroderma, particularly the diffuse form, with a frequency of up to 70%. Scleroderma, or systemic sclerosis (SSc), is a chronic and progressive dermatosis that results in the hardening and immobility of affected skin, with potential involvement of vital organs such as the lungs, esophagus, kidneys, and heart. 

 

Aliases

ENA Scl-70

Scleroderma-70

Anti- Scl-70/anti-topoisomerase antibodies

Anti Scl-70

Specimen type / Specimen volume / Specimen container

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).

Storage and transport instructions

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.

Specimen Rejection Criteria

Quantity not sufficient (QNS)

Hemolysis

Lipemic

Wrong collection container

Biological reference intervals and clinical decision values

Anti-ENA Scl-70 antibodies:

Interpretation of Test Results Reference Values (U/ml)   
Negative < 7
Equivocal 7 - 10
Positive > 10
Turnaround time / Days and times test performed / Specimen retention time

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.