Scleroderma (Scl-70) (ENA) Antibody, IgG
Also known as: SCLER
Use
The presence of Scl-70 antibodies, also known as topoisomerase I or topo-I, is diagnostic for systemic sclerosis (SSc). These antibodies are detected in approximately 20% of SSc patients and are associated with the diffuse form of the disease, which may involve specific organ damage and indicate a poor prognosis. Furthermore, Scl-70 antibodies have been observed in varying percentages of patients with systemic lupus erythematosus (SLE). It is noteworthy that Scl-70, being a DNA binding protein, may result in false positives due to the presence of anti-DNA/DNA complexes in SLE patients' sera. The Scl-70 antibody presence might also be due to potential contamination of recombinant Scl-70 with DNA from cellular material used in immunoassays.
Special Instructions
Strong clinical correlation is recommended if both Scl-70 and dsDNA antibodies are detected. Negative results do not solely exclude the presence of SSc; if suspicion persists, further testing for centromere, RNA polymerase III and U3-RNP, PM/Scl, or Th/To antibodies is advisable.
Limitations
The test may yield false positives due to antibody complexes in SLE patients' sera binding to topo-I. Additionally, contamination of assays can cause false readings, especially where both Scl-70 and dsDNA antibodies are involved. Negative results do not completely rule out systemic sclerosis; further diagnostic testing should be considered if SSc is still suspected.
New York Approved
Methodology
Immunoassay (Multiplex Protein Panel)
Biomarkers
LOINC Codes
- 47322-3
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.5 mL
Container
ARUP standard transport tube
Collection Instructions
Separate serum from cells ASAP or within 2 hours of collection.
Storage Instructions
Refrigerated.
Causes for Rejection
Plasma or other body fluids. Contaminated, hemolyzed, or severely lipemic specimens.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 48 hours |
| Refrigerated | 2 weeks |
| Frozen | 1 year (avoid repeated freeze/thaw cycles) |