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Rheumatology · UK

Rheumatoid factor - a number that needs a story.

RF, anti-CCP and the full inflammatory arthritis screen, drawn once and interpreted by a consultant rheumatologist - with joint ultrasound or MRI on the same visit if the pattern needs it.

See indicative pricing
A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Indicative pricing

What a private rheumatoid factor test costs in the UK.

Indicative ranges across our partner rheumatology clinics and labs.

In short

£95–£165, results in 24–72 hours.

TestIndicative range
Rheumatoid factor (RF) alone £45–£85
RF plus anti-CCP £95–£165
Inflammatory arthritis screen (RF, anti-CCP, CRP, ESR, FBC, urate) £180–£320
Extended autoimmune panel (add ANA, ENA, complement) £280–£480
Consultant rheumatology consultation £220–£380
Joint ultrasound (hands, feet or larger joint) £320–£560
MRI hand or wrist (contrast optional) £450–£850

Prices vary by laboratory and how much of the panel is needed. Consultant rheumatology consultation and joint imaging are separate line items.

The problem

A lone RF number is rarely a diagnosis.

RF is easy to run and easy to over-interpret.

  • Run anti-CCP alongside

    Anti-CCP is more specific for rheumatoid arthritis and often positive years before symptoms. RF alone leaves too many false positives on the table.

  • Read titres, not tick-boxes

    A high-titre RF and a borderline one behave very differently. Quantitative reporting matters.

  • Get imaging when the pattern fits

    Joint ultrasound and MRI catch early synovitis and erosions before X-ray. Same-day access shortens the road to DMARDs when they are needed.

When it helps

When RF testing is the right step.

The situations we see most, plus the one red flag that means A&E rather than a private blood test.

  • Suspected rheumatoid arthritis

    Symmetrical pain and swelling in the small joints of the hands and feet with morning stiffness lasting over 30 minutes - the classic pattern.

  • Family history of rheumatoid arthritis

    A first-degree relative with RA, plus early joint symptoms - RF and anti-CCP help stratify risk before erosions start.

  • Sjögren’s syndrome work-up

    Dry eyes and mouth with fatigue - RF is often positive in Sjögren’s and part of the initial screen alongside anti-Ro and anti-La.

  • Chronic hepatitis C or cryoglobulinaemia

    RF is commonly positive in hepatitis C - the finding is the trigger for viral serology and cryoglobulin testing, not RA treatment.

  • Recurrent joint pain of unclear cause

    Joint pain that does not fit osteoarthritis - younger patients, symmetrical distribution, or a poor response to simple analgesia.

  • Baseline before starting biologics

    RF and anti-CCP status help predict response to certain DMARDs and biologics - a useful baseline before therapy starts.

  • Overlap syndromes and connective tissue disease

    Where lupus, scleroderma or mixed connective tissue disease are suspected, RF sits within a broader autoantibody panel.

  • Red flag: hot swollen single joint

    A single hot, swollen, painful joint with fever is septic arthritis until proven otherwise - same-day A&E, not a private blood test.

Test options

The right panel depends on the pattern.

Each option, explained - from RF alone to full autoimmune serology and imaging.

  • Rheumatoid factor (RF)

    An autoantibody - usually IgM - directed against the Fc portion of IgG. Measured by nephelometry, latex agglutination or ELISA. Reported as IU/mL against a lab reference range.

  • Anti-CCP (ACPA)

    Anti-cyclic citrullinated peptide antibody. More specific for rheumatoid arthritis than RF, often positive years before symptoms. Now standard alongside RF in any inflammatory arthritis work-up.

  • CRP and ESR

    Non-specific inflammatory markers. Useful to gauge activity, monitor treatment response and separate inflammatory from mechanical joint pain.

  • Full blood count and urate

    FBC to look for anaemia of chronic disease or cytopenias; urate to rule out gout, which can mimic early RA and needs a very different treatment path.

  • ANA, ENA and complement

    Where lupus, Sjögren’s, scleroderma or mixed connective tissue disease are suspected - the broader autoimmune serology that puts RF in context.

  • Hand and foot X-ray

    Baseline imaging for suspected RA. Looks for early erosions, joint space narrowing and periarticular osteopenia.

  • Joint ultrasound

    Sensitive for synovitis and early erosive change - often positive before X-ray. Point-of-care in a rheumatology clinic and highly informative in seronegative disease.

  • MRI hand or wrist

    The most sensitive tool for early erosions and bone marrow oedema. Reserved for diagnostic uncertainty or where treatment escalation is being considered.

Safety and interpretation

What to expect afterwards - honestly.

The blood draw is straightforward. The care is in the interpretation and - if inflammatory arthritis is confirmed - the treatment plan.

  • The blood test itself is very low risk

    A small bruise, occasional light-headedness. Phlebotomists are trained to spot and manage the odd faint.

  • A positive RF does not mean you have RA

    About 5% of healthy people have a low-titre positive RF, rising with age. RF is also positive in Sjögren’s, hepatitis C, cryoglobulinaemia, chronic infection and some healthy older adults.

  • A negative RF does not exclude RA

    Around 20–30% of rheumatoid arthritis is seronegative - RF and anti-CCP both negative - especially early. Diagnosis is clinical, supported by imaging and inflammatory markers.

  • Anti-CCP is the more specific marker

    Anti-CCP is over 95% specific for RA and often positive years before symptoms. A high-titre RF plus positive anti-CCP is strongly suggestive.

  • Interpret titres, not just positive/negative

    A high-titre RF has more clinical weight than a borderline positive. Modern reports give a numerical value against a reference range - worth reading carefully.

  • Timing of DMARDs matters

    Early DMARD therapy - ideally within 12 weeks of symptom onset - dramatically reduces joint damage. RF and anti-CCP results speed the referral, they do not replace clinical review.

  • Screen for infections before biologics

    Before starting methotrexate, biologics or JAK inhibitors, we screen for latent TB, hepatitis B and C, and check vaccination status.

  • Pregnancy planning matters

    Some DMARDs are teratogenic and need to be stopped months before conception. RF status itself has no bearing on pregnancy - the treatment plan does.

  • Red flags after starting treatment

    Fever, spreading rash, breathlessness or new mouth ulcers on DMARDs need same-day contact with the rheumatology team, not a routine appointment.

Reading your report

Your RF report in four parts. Read the last one first.

Whichever laboratory ran it, the report the rheumatologist sends you keeps to the same shape.

A UK consultant rheumatologist reviewing a patient’s serology report

A quiet reminder

Immunology language is precise and can read alarmingly - we translate it for you.

If you would like us to talk you through the report and the plan before your GP appointment, just ask.

  1. 01 Header

    RF titre and reference range

    The single number most people look for - RF in IU/mL against the laboratory’s reference range, with positive or negative flagging.

  2. 02 Technique

    Assay method

    Nephelometry, ELISA or latex agglutination. Modern quantitative methods are more reproducible than older qualitative agglutination.

  3. 03 Findings

    Companion markers

    Anti-CCP, CRP, ESR, FBC and urate results with their own reference ranges - the context that turns a lone number into a diagnosis.

  4. 04 Impression

    Rheumatology plan

    Read this first: the likely differential, whether imaging is needed, whether a rheumatology consultation is urgent, and any DMARD discussion.

Recognised by major UK insurers

BupaAXA HealthVitalityAvivaWPACignaHealixBupaAXA HealthVitalityAvivaWPACignaHealixBupaAXA HealthVitalityAvivaWPACignaHealix

Rheumatoid factor and inflammatory arthritis screens are usually covered on outpatient policies when there are joint symptoms. Self-pay is straightforward.

Frequently asked

Everything we get asked about RF.

Quick answers on interpretation, anti-CCP, seronegative RA and cost.

  • What does a positive rheumatoid factor mean?

    It means an autoantibody called rheumatoid factor was detected in your blood. It is a supporting piece of evidence for rheumatoid arthritis, but not a diagnosis on its own. Around 70–80% of people with rheumatoid arthritis are RF positive, but so are 5% of healthy adults, most people with Sjögren’s syndrome, many with chronic hepatitis C, and a smaller proportion with chronic infection or cryoglobulinaemia.

  • Do I have rheumatoid arthritis if my RF is high?

    Not necessarily. A high-titre RF plus symmetrical joint swelling, morning stiffness and raised inflammatory markers is highly suggestive. A high-titre RF in the absence of joint symptoms often needs no treatment but does deserve rheumatology review to look for early clues and plan follow-up.

  • What is the difference between RF and anti-CCP?

    Both are autoantibodies used to diagnose rheumatoid arthritis. RF is more sensitive but less specific - it turns up in many other conditions. Anti-CCP is highly specific for RA (over 95%) and often positive years before symptoms start. Modern practice tests both together.

  • Can rheumatoid factor be negative in rheumatoid arthritis?

    Yes. Around 20–30% of rheumatoid arthritis is seronegative, meaning both RF and anti-CCP are negative. Diagnosis in these patients relies on clinical pattern, inflammatory markers, joint ultrasound or MRI, and response to treatment.

  • How much does a private RF test cost in the UK?

    Roughly £45–£85 for RF alone, £95–£165 with anti-CCP, and £180–£320 for a full inflammatory arthritis screen including CRP, ESR, FBC and urate. A consultant rheumatology consultation is £220–£380 and joint ultrasound £320–£560.

  • How is RF measured and what units are used?

    RF is usually measured by nephelometry or ELISA and reported in international units per millilitre (IU/mL), against a laboratory-specific reference range - commonly under 14 IU/mL. High-titre positives (typically three times the upper limit) carry more clinical weight than borderline results.

  • What happens if my RF is positive but I feel well?

    A rheumatology review is still worthwhile. Most people with an incidental positive RF do not have and never develop RA, but the review pins down whether the positive is meaningful, whether Sjögren’s or hepatitis C need excluding, and whether any follow-up is needed. Often the answer is straightforward reassurance.

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