Ordering Recommendation

Aids in the diagnosis of systemic scleroderma/sclerosis (SSc). Negative results do not rule out SSc. Preferred test is Comprehensive Systemic Sclerosis Panel (3000480).


Semi-Quantitative Multiplex Bead Assay




1-3 days

New York DOH Approval Status

This test is New York DOH approved.

Specimen Required

Patient Preparation

Serum separator tube.

Specimen Preparation

Separate serum from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.2 mL)

Storage/Transport Temperature


Unacceptable Conditions

Plasma or other body fluids. Contaminated, hemolyzed, or severely lipemic specimens.


After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)

Reference Interval

29 AU/mL or less Negative
30-40 AU/mL Equivocal
41 AU/mL or greater Positive

Interpretive Data

The presence of Scl-70 antibodies (also referred to as topoisomerase I, topo-I or ATA) is considered diagnostic for systemic sclerosis (SSc). Scl-70 antibodies alone are detected in about 20 percent of SSc patients and are associated with the diffuse form of the disease, which may include specific organ involvement and poor prognosis. Scl-70 antibodies have also been reported in a varying percentage of patients with systemic lupus erythematosus (SLE). Scl-70 (topo-1) is a DNA binding protein and anti-DNA/DNA complexes in the sera of SLE patients may bind to topo-I, leading to a false-positive result. The presence of Scl-70 antibody in sera may also be due to contamination of recombinant Scl-70 with DNA derived from cellular material used in immunoassays. Strong clinical correlation is recommended if both Scl-70 and dsDNA antibodies are detected.

Negative results do not necessarily rule out the presence of SSc. If clinical suspicion remains, consider further testing for centromere, RNA polymerase III and U3-RNP, PM/Scl, or Th/To antibodies.

Compliance Category



Hotline History


CPT Codes



Component Test Code* Component Chart Name LOINC
0050599 Scleroderma (Scl-70) (ENA) Antibody, IgG 47322-3
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • Anti-Scleroderma (Scl-70) (ENA) Antibody
  • Autoantibodies to Scl 70 Antigen
  • Scl70
  • Scleroderma Antibodies
  • Topo 1
  • Topoisomerase 1 Antibody
  • Topoisomerase I Antibody
Scleroderma (Scl-70) (ENA) Antibody, IgG