Anti-CCP Antibodies

Also written as: CCP, cyclic citrullinated peptide, ACPA

A specific antibody test used mainly when rheumatoid arthritis is being considered.

What it measures

Antibodies against cyclic citrullinated peptides, which are small proteins that have been chemically altered by the body. In some people the immune system reacts to these altered proteins, and the test measures the strength of that antibody response.

Why a doctor orders it

Ordered when rheumatoid arthritis is being considered, usually alongside rheumatoid factor. It is more specific for rheumatoid arthritis than rheumatoid factor and can turn positive early in the course of the condition.

What is generally associated with a higher result

Broadly associated with rheumatoid arthritis, for which it is among the most specific blood markers available. It can occasionally appear in other autoimmune conditions and, rarely, in some chronic infections.

What is generally associated with a lower result

A negative result is generally the expected finding. A portion of people with rheumatoid arthritis remain negative on this test, so a negative result does not by itself rule the condition out.

Everyday things that move this number

Not every shift in a value reflects disease. These are ordinary factors known to affect this particular measurement:

Smoking, which is linked to higher rates of positivity
The laboratory method used, since assays differ between labs
A family history of autoimmune conditions
Rare cross-reactions during long-standing infections

Questions to take to your appointment

How does this result fit together with my rheumatoid factor result and my joint symptoms?
Was the result clearly positive or borderline for this lab's method?
Would a referral to a rheumatologist be worthwhile based on this?

Build a printable questionnaire with your own results →

Where to read more

MedlinePlus, from the US National Library of Medicine, publishes patient-facing pages on individual lab tests and is a reliable next stop: medlineplus.gov/lab-tests .

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