Lab marker · High

High Anti-centromere antibody (ACA): what it means

A Anti-centromere antibody (ACA) result above the normal range is considered high. Here is what a raised Anti-centromere antibody (ACA) 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 strongly associated with limited cutaneous systemic sclerosis (the CREST pattern), and flags a risk of pulmonary hypertension

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What a high Anti-centromere antibody (ACA) can mean

  • Limited cutaneous systemic sclerosis (CREST) — the strong association; supports the diagnosis in someone with typical features.
  • Raynaud's phenomenon — very commonly present, often the first symptom.
  • Higher risk of pulmonary arterial hypertension — the key prognostic concern, needing periodic screening.
  • Usually mutually exclusive with anti-Scl-70 — the two mark different scleroderma patterns.

When to discuss with a doctor

Anti-centromere antibody is tested when systemic sclerosis is suspected — often prompted by Raynaud's phenomenon with skin tightening of the fingers, reflux or dilated skin vessels, and a positive ANA. A positive result supports the limited (CREST) form of the disease and, importantly, flags a raised long-term risk of pulmonary hypertension, so it prompts a rheumatologist to arrange periodic heart and lung screening (such as echocardiography). The diagnosis and the monitoring plan are made by the specialist using the whole clinical picture, not the antibody alone. Mediora.AI can surface a positive anti-centromere antibody alongside ANA so the limited-scleroderma pattern is visible in your results, but confirming the diagnosis and managing the pulmonary risk belongs with your doctor and rheumatologist.

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Mediora.AI is informational - interpretation, not a diagnosis. A single out-of-range value is common and often benign; always discuss decisions with your doctor.