Test ID SCL70 Scl 70 Antibodies, IgG, Serum
Useful For
Evaluating patients with signs and symptoms of scleroderma and other connective tissue diseases in whom the test for antinuclear antibodies is positive
Testing Algorithm
See Connective Tissue Disease Cascade (CTDC) in Special Instructions.
Special Instructions
Method Name
Multiplex Flow Immunoassay
Reporting Name
Scl 70 Ab, IgG, SSpecimen Type
SerumContainer/Tube:
Preferred: Serum gel
Acceptable: Red top
Specimen Volume: 0.5 mL
Specimen Minimum Volume
0.4 mL
Specimen Stability Information
Specimen Type | Temperature | Time |
---|---|---|
Serum | Refrigerated (preferred) | 21 days |
Frozen | 21 days |
Clinical Information
Scl 70 (topoisomerase 1) is a 100-kD nuclear and nucleolar enzyme. Scl 70 antibodies are considered to be specific for scleroderma (systemic sclerosis) and are found in up to 60% of patients with this connective tissue disease. Scl 70 antibodies are more common in patients with extensive cutaneous involvement and interstitial pulmonary fibrosis, and are considered a poor prognostic sign.(1,2)
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.
Reference Values
<1.0 U (negative)
≥1.0 U (positive)
Reference values apply to all ages.
Cautions
Testing for Scl 70 antibodies is not useful in patients without demonstrable antinuclear antibodies.
Day(s) Performed
Monday through Saturday; 4 p.m., Sunday; 11a.m.
Report Available
1 dayPerforming Laboratory

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