Anti-centromere antibody (ACA)
An autoantibody strongly associated with the limited form of scleroderma (systemic sclerosis), often called CREST. A positive result in someone with Raynaud's and skin changes supports the diagnosis and flags a particular risk of raised blood pressure in the lungs.
What it measures
The anti-centromere antibody is an autoantibody directed against proteins of the centromere, the central region of a chromosome. It typically produces a distinctive speckled pattern on ANA testing and is one of the antibodies checked when systemic sclerosis (scleroderma) is suspected. Its key association is with the limited cutaneous form of the disease — historically called CREST syndrome after its features: Calcinosis (calcium deposits under the skin), Raynaud's phenomenon, Esophageal problems (reflux and swallowing difficulty), Sclerodactyly (tight, thickened skin of the fingers), and Telangiectasia (small dilated blood vessels). In this limited form, the skin involvement is confined mainly to the hands, forearms and face, and the disease usually progresses more slowly than the diffuse form. The clinically most important prognostic link is a raised risk of pulmonary arterial hypertension (high blood pressure in the lungs' arteries), which develops over years and needs periodic screening. Anti-centromere and anti-Scl-70 tend to be mutually exclusive and mark different disease patterns — anti-Scl-70 the diffuse form with more lung scarring risk, anti-centromere the limited form with pulmonary hypertension risk. It is a diagnostic and prognostic marker, interpreted by a rheumatologist within the whole picture.
What a high value 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.
What a low value can mean
- Negative — the expected result; makes anti-centromere-associated limited scleroderma unlikely, though other scleroderma antibodies (such as anti-Scl-70) can still be positive.
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.