Anti-CCP antibodies

The upper limit depends entirely on the method: 5, 7, 17 and 20 U/mL are all in use in UK laboratories, and some report only Negative or Positive. Use the range printed by the lab.

Anti-CCP antibodies are antibodies against proteins that have been chemically altered in a particular way (citrullinated) in inflamed joints. They are much more specific to rheumatoid arthritis than rheumatoid factor is, and can appear years before joint symptoms start. The test reports a level, with a cut-off set by the laboratory.

Doctors request it, alongside rheumatoid factor, when someone has joint pain and swelling and rheumatoid arthritis is one of the things being considered. It is not usually repeated once the answer is known.

• Rheumatoid arthritis, in about two thirds of people with it
• Smoking, which raises the chance of a positive in the general population
• Some other autoimmune conditions, less often
• Gum disease, in some studies

• Negative is the usual finding in healthy adults; there is no lower limit
• The level falls a little with treatment in some people, but it rarely turns negative
• A third of people with rheumatoid arthritis never have a detectable level

• About 1 to 2 in 100 healthy adults have a low positive level
• Methods and cut-offs differ widely between laboratories, so a number from one lab does not map onto another's range

No fasting needed. A single value is read alongside rheumatoid factor, CRP and ESR; it is not usually followed over time.

Written by a UK consultant physician. Typical UK adult reference ranges; your laboratory's own printed range takes precedence.