Rheumatoid Arthritis Blood Tests: RF, Anti-CCP and More

Rheumatoid arthritis (RA) is an autoimmune condition in which the immune system attacks the lining of the joints. The main symptoms are joint pain, swelling and stiffness, and some people also feel tired, run a temperature or lose weight. Morning stiffness in RA often lasts longer than the 30 minutes or so that is typical of osteoarthritis.

Blood tests are an important part of diagnosing RA, but no single test can prove or rule it out. This guide explains the main blood tests (rheumatoid factor, anti-CCP antibodies, CRP, ESR and a full blood count), what each one adds, which test to book first, and why swollen joints need a doctor to examine them even when blood results are normal.

Test it in Chiswick: our Rheumatology Check blood test costs £79, with your result explained in person by a practitioner. No GP referral needed. Book this test or call 020 4515 0000.

Quick answer

The main blood tests for rheumatoid arthritis are rheumatoid factor and anti-CCP antibodies, plus CRP and ESR to measure inflammation and a full blood count to check for anaemia. Anti-CCP is the more specific antibody: the NHS says people who test positive are very likely to develop RA. About 1 in 20 people without RA test positive for rheumatoid factor, and some people with RA test negative for both antibodies (seronegative RA). NICE advises referring persistent joint swelling to a specialist, often urgently, even when these blood tests are normal.

Blood tests that can help

Rheumatoid factor

Rheumatoid factor is an antibody. The NHS says more than half of all people with rheumatoid arthritis have high levels when the condition starts, but about 1 in 20 people without RA also test positive. That is why a positive rheumatoid factor on its own does not diagnose RA, and a negative result does not rule it out. NICE recommends offering a rheumatoid factor test to adults with suspected RA. Our Rheumatoid Factor test (£49) measures it on its own.

Anti-CCP antibodies

Anti-CCP (anti-cyclic citrullinated peptide) antibodies are more specific for RA than rheumatoid factor. The NHS says people who test positive for anti-CCP are very likely to develop rheumatoid arthritis, although not everyone with RA has this antibody. NICE advises considering anti-CCP when rheumatoid factor is negative, and measuring it after diagnosis if it has not already been done. Book the Anti-CCP Antibodies test (£59) on its own or as part of the Rheumatology Check.

CRP and ESR

C-reactive protein (CRP) and the erythrocyte sedimentation rate (ESR) both rise with inflammation. The NHS lists them among the blood tests used to help assess inflammation when RA is suspected. Neither is specific to joints, as infections and injuries also raise them, and a normal result does not exclude RA. After diagnosis, NICE recommends measuring CRP alongside disease activity to guide treatment. Our CRP test costs £49 and our ESR test costs £39, or you can have both with a full blood count and ferritin in the Inflammation Check (£79). Our guides to CRP levels and ESR levels explain the numbers.

Full blood count

A full blood count helps rule out other causes of your symptoms. The NHS notes that anaemia is common in people with rheumatoid arthritis, but having anaemia does not prove you have RA. Our Full Blood Count costs £59, and our FAQ on what a full blood count shows explains each part.

Seronegative rheumatoid arthritis

"Seropositive" and "seronegative" describe whether rheumatoid factor and anti-CCP are found in your blood. Some people have RA without either antibody, and the diagnosis is then based on symptoms, examination findings and X-rays or scans. The National Rheumatoid Arthritis Society notes that some people who test negative turn out to have a different inflammatory arthritis, such as psoriatic arthritis, which is another reason a specialist assessment matters.

Tests that help rule out other causes

Gout and lupus can both cause painful, swollen joints. The Rheumatology Check includes uric acid as a first look for gout. An ANA test is useful only if joint pain comes with other features such as rashes, mouth ulcers or extreme tiredness; our guide to lupus blood tests explains when it helps.

Which test should I book?

• A focused start: Rheumatology Check, £79. ESR, rheumatoid factor, anti-CCP antibodies and uric acid, the core blood tests when RA is suspected.
• A broader picture: Rheumatology Extended, £179. Everything in the Rheumatology Check plus ANA and smooth muscle antibodies, useful if another autoimmune condition is possible.
• The fullest view: Muscle and Joint Screen, £129. Rheumatoid factor, CRP, complement C3 and C4, immunoglobulins, uric acid, creatine kinase, vitamin D, iron studies and kidney, liver and bone markers. It does not include anti-CCP or ESR, so it works best alongside the Rheumatology Check.

The rheumatology panels do not include a full blood count or CRP, so you may wish to add the Inflammation Check.

What blood tests cannot tell you

The NHS is clear that no blood test can definitively prove or rule out rheumatoid arthritis. Diagnosis is made by a rheumatologist, using your symptoms, an examination of your joints, blood tests and usually X-rays of the hands and feet. A positive rheumatoid factor in someone without joint swelling is not RA, and normal results do not mean your joints are fine.

The most important finding is joint swelling (synovitis) seen on examination. NICE recommends that any adult with suspected persistent synovitis of undetermined cause is referred for a specialist opinion. Referral should be urgent, even with a normal CRP or ESR and negative rheumatoid factor and anti-CCP, if:

• the small joints of the hands or feet are affected
• more than one joint is affected
• there has been a delay of 3 months or longer between symptoms starting and seeking medical advice

Early treatment matters. Arthritis UK (formerly Versus Arthritis) says intensive treatment started within 12 weeks of symptoms beginning makes remission more likely. If your joints are swollen, see your GP even if your private blood tests are normal, and take your GP feedback report with you.

When to see a GP urgently

Ask for an urgent GP appointment or call NHS 111 if:

• you have severe pain in one joint that started suddenly, or you find it difficult to move a joint
• the skin around a joint is swollen, hot or has changed colour
• you have joint pain and feel generally unwell, with a high temperature or feeling hot, cold or shivery, as this can be septic arthritis (an infection in the joint)

See your GP soon, rather than waiting for results, if you have swollen joints in your hands or feet, swelling in more than one joint, or stiffness that has lasted for weeks.

Frequently asked questions

Can you have rheumatoid arthritis with negative blood tests?

Yes. Some people with RA have neither rheumatoid factor nor anti-CCP antibodies, which is called seronegative RA, and CRP and ESR can be normal. NICE advises specialist referral for suspected persistent joint swelling, and urgent referral if the small joints of the hands or feet or more than one joint are affected, even when blood tests are normal.

What does a positive rheumatoid factor mean?

It means the antibody was found in your blood. More than half of people with RA are positive when the condition starts, but so are about 1 in 20 people without it, so the result is read alongside your symptoms, an examination and usually an anti-CCP test.

Is anti-CCP better than rheumatoid factor?

Anti-CCP is more specific, so a positive result points more strongly towards RA. Neither test picks up everyone with RA, which is why they are often done together.

Is CRP always raised in rheumatoid arthritis?

No. CRP and ESR are often raised when RA is active, but they can be normal. They are more useful for tracking inflammation over time than for making the diagnosis.

Do I need a GP referral for these tests?

Not for a private blood test at Omnia. For a diagnosis and treatment you will need your GP and a rheumatologist, and our practitioner can provide a GP feedback report to support that conversation.

Rheumatoid arthritis blood tests in Chiswick

Omnia Lifestyle is at 8 to 9 Bedford Corner, The Avenue, Chiswick, London W4 1LZ, a short walk from Turnham Green station (District line; Piccadilly line trains stop there early morning and late evening only) and served by buses 94, E3 and 272. Limited parking is available on request when you book. Every clinic test price includes your sample taken at the clinic, analysis at the Randox accredited laboratory, a practitioner review of your result with you, and a GP feedback report on request. You do not need a GP referral, and most results are back within a few working days.

Useful links: book the Rheumatology Check, browse our autoimmune and inflammation blood tests, or compare every blood test and price. Our guide to blood tests for joint pain covers other causes of aching joints. If you would like support alongside your GP care, see our arthritis care at Omnia.

This article is general information, not medical advice. Discuss your results with your GP or practitioner.