Scl-70 Ab ELISA Kit (Scleroderma 70)

Full Name: Scl-70 Ab ELISA Kit (Scleroderma 70)
Reactivity: Human
Sample Type: Serum, Plasma
Sensitivity: 1.0 U/ml


Scl-70 (Scleroderma 70)(also called Topoisomerase 1) is a nucleolar and nuclear enzyme which is regarded as being specific for systemic sclerosis (scleroderma) and it can be found in over 60% of patients possessing this connective tissue disease. Anti-Scl-70 and anti-centromere antibodies (ACA) are particularly useful in distinguishing patients having systemic sclerosis (SSc), these antibodies are associated with more severe scleroderma disease.


Scl-70 is an autoantibody that targets the topoisomerase I enzyme, which is involved in DNA replication and repair. The presence of Scl-70 in the blood is strongly associated with diffuse systemic sclerosis, a subtype of the disease characterized by widespread skin involvement and internal organ damage. Studies have shown that up to 60% of patients with diffuse systemic sclerosis have positive Scl-70 antibodies.

Patients with positive Scl-70 antibodies may benefit from more aggressive immunosuppressive therapies to prevent or mitigate organ damage. It is worth noting that Scl-70 testing should always be interpreted in conjunction with a patient’s clinical presentation and other diagnostic findings.


All reagents supplied need to be stored at 2 °C – 8 °C, unopened reagents will retain reactivity until expiration date. Do not use reagents beyond this date.

  • Divisible Microplate: Consisting of 12 modules of 8 wells, highly purified Scl-70 antibodies bound to microwells.
  • Calibrators (A-F): Concentration 0-200 U/ml, made up from anti-Scl-70 in a serum/buffer matrix.
  • Controls Positive and Control Negative: Containing anti-Scl-70 antibodies.
  • Sample Buffer (5x).
  • Enzyme Conjugate: Contains anti-human IgG antibodies, HRP labelled.
  • TMB Substrate.
  • Stop Solution: Contains acid.
  • Wash Buffer (50x Concentrated).
  • Instruction Manual.
  • Certificate of Analysis.


The minimum detection sensitivity level of human anti-Scl 70 antibody (Scleroderma 70, anti-Scl-70, Scl-70 Ab, topoisomerase 1, anti-topoisomerase 1, topo-1) IgG autoantibodies using current Scl-70 Ab ELISA kit was 1.0 U/ml. The dynamic range for this assay is 12.5 – 200.0 U/ml.


– Expected Values: Cut-off 25 U/ml.
– Limit Of Detection (LOD): 1 U/ml.
– Measuring Range: 0 – 200 U/ml
– Interference: None.
– Results Interpretation: Negative: < 15 U/ml, Borderline 15-25 U/ml, Positive: ≥ 25 U/ml.
– Intra Assay: 3.2 – 4.0%
– Inter Assay: 2.3 – 2.8%
– Linearity: 97 – 104%
– Clinical Diagnosis: Sensitivity (76.0%), Specificity (99.0%), Overall agreement (94.4%).


  1. An enzyme-linked immunosorbent assay for autoantibodies against the nuclear protein Scl-70. J Immunol Methods. (1985) 80 (2): 211-9. Geisler C. and Høier-Madsen M.
  2. Anti-Scl-70 (topo-I) antibodies in SLE: Myth or reality? Autoimmun Rev. (2010) 9 (11): 756-60. Review. Mahler M., et al.
  3. Development and comparative evaluation of immunoblot assays for detecting autoantibodies to Scl 70 and Jo 1 antigens in serum. Clin Chem. (1990) 36 (12): 2053-6. Fonong T., et al.
  4. High titers of autoantibodies to topoisomerase I (Scl-70) in sera from scleroderma patients. Science. (1986) 231 (4739): 737-40. Shero J.H., et al.
  5. Scl 70 autoantibodies from scleroderma patients recognize a 95 kDa protein identified as DNA topoisomerase I. Chromosoma. (1986) 94 (2): 132-8. Guldner H.H., et al.
  6. Anti-scl-70. Autoimmunity. (2005) 38 (1): 65-72. Review. Basu D. and Reveille JD.


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