Low Anti-Scl-70 (anti-topoisomerase I) antibody: what it means
A Anti-Scl-70 (anti-topoisomerase I) antibody result below the normal range is considered low. Here is what a reduced Anti-Scl-70 (anti-topoisomerase I) antibody can point to, and when it is worth discussing with a doctor.
Reference range: Typically <7 U/mL negative (assay-dependent); a positive result is highly specific for systemic sclerosis (scleroderma), particularly the diffuse form with a higher risk of lung and kidney involvement
Understand your full resultWhat a low Anti-Scl-70 (anti-topoisomerase I) antibody can mean
- Negative — the expected result; makes anti-Scl-70-associated scleroderma unlikely, though other scleroderma antibodies (such as anticentromere) can still be positive.
When to discuss with a doctor
Anti-Scl-70 is tested when systemic sclerosis is suspected — for example with Raynaud's phenomenon, skin thickening or puffy fingers and a positive ANA. A positive result is highly specific and strongly supports scleroderma in the right clinical setting, and because it flags a higher risk of lung and kidney involvement, it prompts a rheumatologist to arrange closer monitoring (such as lung function tests and blood-pressure and kidney checks). The diagnosis and the monitoring plan are made by the specialist, using the whole picture rather than the antibody alone. Mediora.AI can surface a positive anti-Scl-70 alongside ANA so the scleroderma pattern is visible in your results, but confirming the diagnosis and managing the organ risks belongs with your doctor and rheumatologist.
Conditions this can relate to
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