What is anti-CCP?
In rheumatoid arthritis the immune system turns against your own joints. One of the first steps is that proteins in the body undergo a small chemical change, citrullination, after which the immune system sees them as foreign and makes antibodies against them. Anti-CCP measures those antibodies, against a laboratory-built version of such modified proteins. Those antibodies are remarkably faithful to one disease. Where the older rheumatoid factor also occurs with infections, other autoimmune diseases and healthy older people, anti-CCP belongs almost exclusively to rheumatoid arthritis. A positive result therefore makes that diagnosis likely, and the antibodies are often present years before a joint hurts. Conversely, about a third of people with rheumatoid arthritis have no anti-CCP, so negative does not rule the disease out. Your report shows anti-CCP as a number with a limit: below 7 the result is called negative, above 10 positive, and in between equivocal. The unit differs per lab and the numbers cannot be swapped between labs; the higher above the limit, the more certain the result.
Why is anti-CCP relevant?
Rheumatoid arthritis is a disease in which starting treatment early makes the difference between joints that stay intact and joints that deform. The first months after the first complaints are the window in which the disease can still be tamed. Anti-CCP is the number that helps recognise that window: in someone with painful, swollen joints, stiff in the morning and on both sides, a positive result makes the diagnosis likely and the step to a rheumatologist urgent. That is also the reason not to have it measured casually. Without joint complaints a positive result says there is an increased chance of rheumatoid arthritis in the coming years, not that it is there, and there is no treatment that prevents the disease at that point. Anyone who tests positive without complaints is mainly left with worry. That is why this is a test for complaints, and not part of a health check. What you do control comes beforehand. Smoking is the strongest lifestyle factor behind these antibodies: smoke sets in motion in the lungs exactly the citrullination the immune system reacts to, and smokers more often get the anti-CCP-positive, more stubborn form of the disease. Inflamed gums and excess weight contribute too. For anyone with a parent or sibling with rheumatoid arthritis, not smoking and healthy gums are the best prevention there is.
Anti-CCP decision limits
What counts beside the number:
- Your joints: which ones, for how long, on both sides, and how stiff in the morning
- Rheumatoid factor, which is more sensitive but less specific; both positive is the strongest pattern
- CRP and ESR, which show whether there is inflammation at that moment
- How far the value sits above the limit: higher is more certain
- Smoking, gum inflammation and excess weight, the factors you influence yourself
- Rheumatoid arthritis in the family
The rows above are limits, not normal values: below the number the result is called negative and above it positive. They stand without a unit, because each lab uses its own unit and the numbers cannot be swapped between labs; read your result against the limit on your own report. In general practice the test is no longer used as a first step when rheumatoid arthritis is suspected, because the diagnosis is made on the joints and not on blood alone; with complaints the rheumatologist is where blood and joints are looked at together.
What Dutch labs actually use
Anti-CCP has no normal value with an upper and a lower bound. The four labs publish a cut-off, and they put it in almost the same place: Unilabs and Clinical Diagnostics print below 7, Star-shl starts its negative step below 7 as well, and Certe runs its band from 0 to 10. Star-shl is the only one of the four that cuts the scale into three steps: negative below 7, equivocal from 7 to 10, positive above 10. The other three draw a single line. A result of 8 therefore falls inside Certe's band and in Star-shl's equivocal zone. What does differ per lab is the unit they write it in. Unilabs writes kU/l, Star-shl IU/ml, Certe arb'U/mL and Clinical Diagnostics E/ml. Four notations for the same two figures, so read your result beside the unit and the limit your own lab prints with it.
0 – 7kU/l
Between 7 and 10 it depends on the lab, because each sets its limit on its own method. Above 10 every lab calls it raised.
From 0 – 7 kU/l no lab calls it raised. Between 7 and 10 it depends on the lab.
Every age, per lab
| Laboratory | Group | Reference range |
|---|---|---|
| Unilabs(Saltro, Medlon, SHO, Atalmedial)2026 | All ages | < 7 kU/lDecision limit |
| Star-shl2026 | Negative | < 7 IU/mlDecision limit |
| Equivocal | 7–10 IU/mlDecision limit | |
| Positive | > 10 IU/mlDecision limit | |
| Certe2026 | All ages | 0–10 arb'U/mLDecision limit |
| Clinical Diagnostics2026 | All ages | < 7 E/mlDecision limit |
Each band as the lab publishes it, retrieved in 2026, unless marked otherwise.
Anti-CCP high or low: what it means
A positive anti-CCP is almost always rheumatoid arthritis or its early stage; the higher the value, the more certain. With joint complaints that is a reason to see a rheumatologist quickly, because early treatment protects the joints. Without complaints it means an increased chance in the coming years, and then stopping smoking, healthy gums, a healthy weight and staying alert to swollen joints are what you can do. Rarely a positive result occurs with another autoimmune disease, such as the arthritis of psoriasis or Sjögren's syndrome. A negative anti-CCP does not rule rheumatoid arthritis out: about a third of people with the disease do not have the antibody, and in them the diagnosis is made on the joints themselves, rheumatoid factor and the inflammation values. A negative result with complaints is therefore not an endpoint. An equivocal result, between 7 and 10, is repeated after a few months, because the antibody usually keeps rising as the disease develops. Set anti-CCP beside rheumatoid factor, which is more sensitive but less specific: both positive is the strongest pattern. CRP and ESR show whether there is inflammation at that moment. And the most important thing is not on the report: which joints, for how long, and how stiff in the morning.
What lowers it
Negative is the ordinary outcome, and does not rule rheumatoid arthritis out.
| Cause | How often |
|---|---|
| Rheumatoid arthritis without anti-CCPAbout a third of people with the disease do not have the antibody; the diagnosis is then made on the joints, rheumatoid factor and the inflammation values | Sometimes |
What raises it
Almost always rheumatoid arthritis or its early stage; smoking makes the antibody more likely.
| Cause | How often |
|---|---|
| Rheumatoid arthritisThe antibody belongs almost exclusively to this disease and is often present years before the first complaints; the higher the value, the more certain | Often |
| SmokingSmoke sets in motion in the lungs the citrullination the immune system reacts to; smokers more often get the anti-CCP-positive form of rheumatoid arthritis | Sometimes |
| Psoriatic arthritis, Sjögren's or lupusRarely positive in the arthritis that goes with psoriasis, Sjögren's syndrome or lupus | Rare |
How does an anti-CCP blood test work?
- Referral
- Not needed to have the test done, but this is a test for joint complaints and not screening: without complaints a positive result mainly brings worry.
- Fasting
- Not needed.
- The draw
- One tube of blood from a vein in your arm, usually together with rheumatoid factor, CRP and ESR.
- The result
- A single number with a limit: below 7 negative, above 10 positive, in between equivocal. The unit differs per lab and the numbers cannot be swapped between labs.
- Repeating
- An equivocal result after a few months. A negative result with persistent complaints too, because the antibody can appear later. A positive result does not need repeating.
- Where to draw
- You can draw at 250+ locations near you, no referral needed. See the locations
Frequently asked questions
What is anti-CCP?
An antibody the immune system makes against proteins of your own that have undergone a small chemical change, citrullination. In rheumatoid arthritis that is one of the first steps of the disease, and anti-CCP is therefore the most specific clue to that disease to be found in blood. The antibody is often present years before a joint hurts.
What is a normal anti-CCP level?
There is no normal value, only a limit: below 7 the result is negative, above 10 positive, and in between equivocal. Negative is the ordinary outcome in most people without complaints. The unit differs per lab, so compare your result with the limit on your own report and not with a number from another lab.
What does a positive anti-CCP mean?
That the chance of rheumatoid arthritis is high, now or in the coming years; the higher the value, the more certain. With painful, swollen joints that are stiff in the morning, that is a reason to see a rheumatologist quickly, because early treatment protects the joints. Without complaints it means an increased chance, not a disease; then not smoking, healthy gums and staying alert to swollen joints are what you can do.
What does a negative anti-CCP mean?
In most people: nothing special. With joint complaints a negative result does not rule rheumatoid arthritis out, because about a third of people with the disease do not have the antibody. The diagnosis is then made on the joints themselves, rheumatoid factor and the inflammation values, and with persistent complaints the test is repeated after a while.
Can I have anti-CCP measured to rule out rheumatoid arthritis?
Better not. The test is meant for joint complaints, not for screening. A negative result does not rule the disease out, and a positive result without complaints gives an increased chance in the coming years without there being a treatment that prevents the disease at that point. Anyone who tests without complaints is mainly left with worry. With a parent or sibling with rheumatoid arthritis, not smoking and healthy gums are the meaningful prevention.
What does smoking have to do with anti-CCP?
A lot. Smoke sets in motion in the lungs exactly the chemical change of proteins, citrullination, the immune system reacts to in rheumatoid arthritis. Smokers make anti-CCP more often, more often get the anti-CCP-positive and more stubborn form of the disease, and respond less well to treatment. Stopping smoking is the most important lifestyle step with this antibody, before and after the diagnosis.
What is the difference with rheumatoid factor?
Rheumatoid factor is the older test and is more sensitive but less specific: it also occurs with infections, other autoimmune diseases and healthy older people. Anti-CCP belongs almost exclusively to rheumatoid arthritis. That is why they are determined together: both positive is the strongest pattern, and only rheumatoid factor positive calls for more context.
Do I need to fast?
No. Have rheumatoid factor, CRP and ESR taken in the same draw, because anti-CCP is never read alone.
Which tests include anti-CCP?
Anti-CCP is measured in the Autoimmunity & coeliac module, on top of another draw. It is not orderable yet.
Related biomarkers
Sources
- 1.LESA Laboratory diagnostics (Dutch primary-care laboratory agreement). 2026. richtlijnen.nhg.org
- 2.Unilabs, test catalogue (Dutch): anti-CCP. 2026. bepalingenklapper.nl
- 3.Star-shl, test catalogue (Dutch): anti-CCP. 2026. star-shl.nl
- 4.Certe, test catalogue (Dutch): anti-CCP. 2026. bepalingenwijzer.certe.nl
- 5.Clinical Diagnostics, lab guide (Dutch): anti-CCP. 2026. clinicaldiagnostics.nl
Educational information only, not medical advice. Consult a healthcare professional for clinical decisions.
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Anti-CCP is measured in the Autoimmunity & coeliac module, on top of another draw. It is not orderable yet.
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