The anti-centromere antibody test looks for autoantibodies against proteins in the centromere, the part of a chromosome that helps it separate during cell division. A positive result is strongly associated with limited cutaneous systemic sclerosis, the form of scleroderma in which skin thickening is mainly confined to the fingers, hands, forearms, feet, lower legs, and sometimes the face. It is also linked with the cluster of features historically called CREST syndrome: calcinosis, Raynaud phenomenon, esophageal dysfunction, sclerodactyly, and telangiectasia.
The result does not diagnose systemic sclerosis on its own. Some people test positive years before clear symptoms develop, while others have the antibody with another autoimmune condition or never develop systemic sclerosis. In a person who already has scleroderma, anti-centromere antibodies help describe the likely disease pattern and guide long-term screening, especially for pulmonary arterial hypertension. The antibody level itself usually does not measure disease severity, and repeating it frequently is rarely useful. Doctors interpret it with symptoms, examination findings, nailfold capillaries, lung tests, heart screening, and other autoantibodies.
- A positive anti-centromere antibody strongly supports limited cutaneous systemic sclerosis when typical symptoms and examination findings are present.
- The antibody is commonly linked with Raynaud phenomenon, sclerodactyly, telangiectasia, and later pulmonary arterial hypertension risk.
- Anti-centromere positivity usually carries a lower interstitial lung disease and renal crisis risk than some other scleroderma antibodies, but neither risk is zero.
- Laboratories may detect a centromere ANA pattern or antibodies to CENP-B, CENP-A, or related centromere proteins; cutoffs vary by method.
- No fasting is normally needed, and the test usually requires only a standard blood sample.
Table of Contents
- What the Anti-Centromere Test Detects
- How It Relates to Limited Scleroderma and CREST
- What Positive, Negative, and Borderline Results Mean
- Health Risks and Monitoring After a Positive Result
- Testing Methods, Preparation, and Reference Ranges
- Other Conditions and Antibodies to Consider
- Practical Next Steps
What the Anti-Centromere Test Detects
Anti-centromere antibodies, often shortened to ACA, are antinuclear antibodies directed against proteins found at chromosome centromeres. The best-known targets are centromere protein B, or CENP-B, and centromere protein A, or CENP-A. Some laboratory panels also evaluate CENP-C or related proteins.
The antibody may first appear as a distinctive pattern on an antinuclear antibody test performed by indirect immunofluorescence. Under the microscope, cells show many discrete nuclear dots in resting cells and bright staining aligned with chromosomes in dividing cells. The International Consensus on ANA Patterns calls this the centromere pattern, AC-3. A laboratory may then confirm the target with an enzyme immunoassay, chemiluminescent assay, line blot, or another solid-phase method.
These methods are related but not interchangeable. An ANA immunofluorescence result describes a visual pattern and titer, while a CENP-B or CENP-A immunoassay reports reactivity to a specific antigen. A person can occasionally have a classic centromere pattern with a negative CENP-B assay because the antibody recognizes a different centromere protein. The reverse can also occur, especially at low levels or with highly sensitive multiplex tests.
Anti-centromere antibodies are considered systemic-sclerosis–specific antibodies because they are uncommon in people without autoimmune disease and have a strong association with a recognizable systemic sclerosis phenotype. However, “specific” does not mean exclusive. ACA may occur in primary biliary cholangitis, Sjögren syndrome, systemic lupus erythematosus, rheumatoid arthritis, or an undifferentiated connective tissue disease.
A positive result becomes most meaningful when it matches clinical findings. For example, long-standing Raynaud phenomenon, puffy fingers, abnormal nailfold capillaries, fingertip pits, and a centromere antibody create a much stronger systemic sclerosis signal than the antibody alone. A broader connective tissue disease blood test panel may help when the symptoms do not yet fit one clear diagnosis.
How It Relates to Limited Scleroderma and CREST
Anti-centromere antibodies are most closely associated with limited cutaneous systemic sclerosis. “Limited” describes the distribution of skin thickening, not a harmless or purely skin-limited disease. Internal organs can still be affected, and complications may emerge after many years.
The older term CREST summarizes five common manifestations:
- Calcinosis: calcium deposits under the skin, often over fingers, elbows, or pressure points.
- Raynaud phenomenon: fingers or toes change color with cold or stress because small blood vessels constrict.
- Esophageal dysfunction: reflux, swallowing difficulty, or impaired movement of food through the esophagus.
- Sclerodactyly: tight, thickened skin of the fingers that can limit movement.
- Telangiectasia: small, widened blood vessels visible on the face, lips, hands, or inside the mouth.
Not every ACA-positive person has all five features. Modern clinicians usually use “limited cutaneous systemic sclerosis” because it better reflects the full disease spectrum. Some people have only Raynaud phenomenon and abnormal capillaries at first. Others develop skin or organ findings gradually. A few have systemic sclerosis without obvious skin thickening, sometimes called systemic sclerosis sine scleroderma.
ACA-positive disease often progresses more slowly than anti-topoisomerase I–positive diffuse systemic sclerosis. Severe early interstitial lung disease, rapid widespread skin thickening, and scleroderma renal crisis are less common on average. That relative difference should not be mistaken for protection. ACA-positive patients can still develop lung fibrosis, digital ulcers, gastrointestinal disease, heart involvement, or kidney problems.
The clearest long-term association is pulmonary vascular disease. People with limited cutaneous systemic sclerosis and ACA have an increased risk of pulmonary arterial hypertension, a condition in which pressure rises in the arteries carrying blood from the heart to the lungs. PAH may not appear until many years after Raynaud phenomenon begins, so continuing surveillance matters even when skin disease seems stable.
The antibody helps classify a pattern, but it is not believed to act as a simple on-off cause of every CREST feature. Systemic sclerosis results from interacting vascular, immune, and fibrotic processes. ACA may contribute to disease biology, but its most established clinical role is as a diagnostic and prognostic biomarker.
What Positive, Negative, and Borderline Results Mean
A positive anti-centromere result means the laboratory detected antibody binding to one or more centromere proteins or identified a centromere ANA pattern. Its interpretation depends on the method, strength of the result, ANA titer, and reason for testing.
| Result | Likely interpretation | Important limitation |
|---|---|---|
| Strong positive with classic centromere ANA pattern | Strongly supports limited systemic sclerosis when compatible clinical features are present | Does not establish organ involvement or disease severity |
| Low positive on a solid-phase assay | May represent early autoimmunity, another autoimmune disease, or an assay-specific finding | Needs correlation with ANA pattern, symptoms, and examination |
| Positive without symptoms | May precede disease or remain an isolated finding | Cannot predict with certainty whether systemic sclerosis will develop |
| Negative | Makes the ACA-associated phenotype less likely | Does not rule out systemic sclerosis or another connective tissue disease |
A positive result is not the same as a diagnosis. Systemic sclerosis is diagnosed from a combination of skin changes, vascular findings, internal-organ features, nailfold capillaroscopy, and autoantibodies. Classification criteria assign weight to ACA, but those criteria were designed mainly to create consistent research groups and should support rather than replace clinical judgment.
A negative result also needs context. Many people with systemic sclerosis have another disease-specific antibody, such as anti-Scl-70, anti-RNA polymerase III, anti-fibrillarin, anti-Th/To, or anti-PM/Scl. Some have no currently identified disease-specific antibody. The related scleroderma antibody panel can show whether a different pattern better fits the clinical picture.
The numeric antibody level usually has limited value for tracking disease. ACA often remains positive for years, including during stable periods. Higher values do not reliably mean more severe skin disease, higher pulmonary pressure, or a need for stronger treatment. For that reason, routine serial antibody measurements are generally less useful than repeat lung, heart, kidney, and symptom assessments.
A borderline result may deserve confirmation, especially when it came from a broad multiplex screen in someone with low pretest probability. Checking ANA by immunofluorescence and reviewing the pattern can clarify whether the result represents a coherent centromere response. Clinicians should avoid diagnosing systemic sclerosis from a weak isolated signal in a person without Raynaud phenomenon, skin findings, capillary abnormalities, or organ features.
Health Risks and Monitoring After a Positive Result
Once systemic sclerosis is suspected or confirmed, the anti-centromere result helps determine which complications deserve sustained attention. It does not replace standard screening, because organ disease can be silent at first.
Pulmonary arterial hypertension
PAH is a major concern in ACA-positive limited systemic sclerosis. Early symptoms can be subtle: reduced exercise tolerance, shortness of breath on stairs, unusual fatigue, chest pressure, lightheadedness, or ankle swelling. By the time symptoms become obvious, disease may already be advanced.
Many specialist programs screen at least yearly with a combination of symptom review, pulmonary function tests including diffusing capacity, echocardiography, and biomarkers such as NT-proBNP. Some patients meet criteria for the DETECT algorithm, which combines noninvasive variables to decide who should undergo echocardiography and right-heart catheterization. Right-heart catheterization is required to confirm PAH; an echocardiogram estimates probability but does not make the final diagnosis.
Interstitial lung disease
ACA is associated with a lower average risk of severe interstitial lung disease than anti-Scl-70, yet ACA-positive patients can still develop fibrosis or other lung problems. Baseline pulmonary function testing is common, and many clinicians obtain high-resolution chest CT when systemic sclerosis is diagnosed or when symptoms, examination, or lung tests raise concern. A falling forced vital capacity or diffusing capacity needs evaluation rather than attribution to the antibody pattern alone.
Digital and gastrointestinal disease
Raynaud attacks, fingertip ulcers, calcinosis, and telangiectasias can substantially affect quality of life. Repeated ischemia can cause painful ulcers or tissue loss. New persistent fingertip pain, a dark or pale area that does not recover, drainage, redness, or fever requires prompt attention.
Reflux and impaired esophageal movement are common. Untreated reflux can disturb sleep, injure the esophagus, and possibly worsen aspiration-related lung problems. Difficulty swallowing, food sticking, weight loss, vomiting blood, or black stool warrants medical assessment.
Liver autoimmunity
ACA can occur in primary biliary cholangitis, an autoimmune disease affecting small bile ducts. This association is most relevant when alkaline phosphatase is elevated, itching is unexplained, or antimitochondrial antibodies are present. A positive ACA by itself does not diagnose liver disease, but abnormal liver tests should not be ignored.
The key point is that the antibody guides vigilance rather than predicting an exact outcome. A person may remain stable for decades, while another develops a complication despite modest skin involvement. Individual follow-up should reflect symptoms, disease duration, prior results, and other risk factors.
Testing Methods, Preparation, and Reference Ranges
The test uses blood drawn from a vein. Fasting is usually unnecessary, and normal daily medicines can generally be continued. The ordering clinician may combine it with ANA testing, an extractable nuclear antigen panel, inflammatory markers, blood counts, kidney and liver tests, or other systemic sclerosis antibodies.
Laboratories may report anti-centromere testing in several ways:
- ANA by indirect immunofluorescence: gives a titer, such as 1:160 or 1:640, and a centromere pattern.
- CENP-B or CENP-A immunoassay: gives negative, equivocal, or positive categories, sometimes with an index or units.
- Line immunoblot or multiplex panel: reports several systemic sclerosis antibodies together.
There is no universal numeric normal range. Each manufacturer establishes its own cutoff, and values from two methods may not be comparable. The report’s reference interval and method should always accompany interpretation.
ANA titers reflect how far the serum remains reactive after dilution. A higher titer generally makes an autoimmune association more credible, but the exact number does not grade organ damage. The ANA by IFA titer and pattern can be useful when a specific-antigen result is weak or unexpected.
Recent infection, age, or another autoimmune condition can influence ANA findings, but there is no special preparation that removes those effects. Immunosuppressive therapy may alter some antibodies, yet ACA often persists. A person should not stop treatment for testing.
The physical risks are limited to those of an ordinary blood draw, such as brief pain, bruising, or lightheadedness. Results may return within a few days; specialized panels can take longer.
Other Conditions and Antibodies to Consider
Anti-centromere antibodies define only one systemic sclerosis subset. Distinguishing antibody patterns can help clinicians anticipate different complications without assuming that any result is destiny.
- Anti-Scl-70, or anti-topoisomerase I: more strongly associated with interstitial lung disease and diffuse skin involvement. The anti-Scl-70 antibody test is often included in first-line scleroderma testing.
- Anti-RNA polymerase III: associated with rapidly progressive diffuse skin disease and a higher scleroderma renal crisis risk. It may also influence cancer screening around disease onset in selected patients.
- Anti-Th/To: often linked with limited cutaneous disease but may carry meaningful lung and pulmonary hypertension risk.
- Anti-fibrillarin, or U3 RNP: associated with diffuse disease and internal-organ involvement in some populations.
- Anti-PM/Scl and anti-Ku: can suggest overlap with inflammatory myopathy.
Most systemic sclerosis–specific antibodies are mutually exclusive, but exceptions occur, especially with modern multiplex assays. An unexpected double-positive result should be interpreted carefully and may need confirmation by another method.
Other diagnoses can imitate parts of limited systemic sclerosis. Primary Raynaud phenomenon can cause color changes without autoimmune vascular damage. Eosinophilic fasciitis, scleredema, diabetic cheiroarthropathy, nephrogenic systemic fibrosis, and certain exposures can cause skin tightening. Reflux, isolated telangiectasias, or calcinosis also have many non-scleroderma causes.
Primary biliary cholangitis is an important autoimmune association. Sjögren syndrome can coexist with systemic sclerosis or produce ACA positivity without classic scleroderma. Dry eyes and mouth, parotid swelling, dental decay, or abnormal liver tests may justify targeted evaluation rather than assuming every symptom belongs to one disease.
Practical Next Steps
A positive result should lead to a focused clinical review, not immediate fear or treatment. The first question is whether there are features of systemic sclerosis or another autoimmune disease.
A practical evaluation may include:
- A detailed history of Raynaud attacks, finger swelling, skin tightening, fingertip sores, reflux, swallowing difficulty, breathlessness, chest symptoms, and exercise tolerance.
- Examination of skin distribution, telangiectasias, calcinosis, digital pits, blood pressure, and heart and lung findings.
- Nailfold capillaroscopy when available to look for the characteristic microvascular changes of systemic sclerosis.
- Baseline pulmonary function tests and consideration of high-resolution chest CT.
- Echocardiography and other PAH screening tests, repeated at an interval set by the specialist.
- Kidney function, urinalysis, blood pressure monitoring, and liver tests when clinically appropriate.
A rheumatology referral is appropriate when ACA is positive and the person has Raynaud phenomenon, puffy fingers, abnormal nailfold capillaries, skin thickening, unexplained lung or heart symptoms, or another systemic autoimmune feature. A person with an isolated low-positive result and no symptoms may need confirmation and periodic clinical observation rather than a full disease label.
Seek urgent care for severe new shortness of breath, chest pain, fainting, coughing blood, a persistently blue or black fingertip, rapidly worsening swelling, or a marked blood-pressure rise with headache or neurologic symptoms. These problems cannot be interpreted safely through an antibody result alone.
For established systemic sclerosis, the most valuable follow-up is consistent organ screening. Keep copies of the assay method and ANA pattern, but focus on changes in breathing, circulation, swallowing, skin, blood pressure, and objective heart and lung tests. Anti-centromere antibodies are a durable clue to the disease pattern; day-to-day care depends on what the body is actually doing.
References
- The clinical utility of autoantibodies in systemic sclerosis: a review with a focus on cohort differences and standardization 2025 (Review)
- The prognostic power of anti-topoisomerase I and anti-centromere antibodies in systemic sclerosis – A systematic review of the literature 2025 (Systematic Review)
- Pathogenic role of anti-nuclear autoantibodies in systemic sclerosis: Insights from other rheumatic diseases 2024 (Review)
- Systemic Sclerosis-Specific Antibodies: Novel and Classical Biomarkers 2022 (Review)
- Systemic Sclerosis-Associated Pulmonary Arterial Hypertension 2024 (Review)
- EULAR recommendations for the treatment of systemic sclerosis: 2023 update 2025 (Guideline)
Disclaimer
This article is general educational information and does not diagnose systemic sclerosis, CREST syndrome, pulmonary hypertension, or another autoimmune disease. Anti-centromere results and screening needs must be interpreted by a qualified clinician using the test method, symptoms, examination, and organ assessments; urgent heart, lung, or circulation symptoms require prompt care.
