Rheumatoid Arthritis (RA)

Causes & Risk Factors

The exact cause of RA is not fully understood, but it is believed to result from a combination of genetic susceptibility and environmental triggers that lead the immune system to attack joint tissue.

• Genetic predisposition — certain genetic markers (such as HLA-DRB1) are associated with a higher risk of developing RA, particularly when combined with other risk factors.

• Sex — RA is two to three times more common in women than in men, suggesting a hormonal influence on disease development.

• Age — RA can begin at any age but most commonly starts between 30 and 60 years.

• Smoking — one of the most significant modifiable risk factors; smoking increases both the risk of developing RA and disease severity.

• Family history — having a close relative with RA or another autoimmune disease increases individual risk.

• Obesity — associated with increased inflammatory burden and may influence disease onset and severity.

Symptoms & When to Test

RA symptoms often develop gradually over weeks to months, though some patients experience a more rapid onset.

• Persistent joint pain, swelling, and tenderness — typically affecting small joints of the hands and feet first

• Symmetric joint involvement — similar joints affected on both sides of the body

• Morning stiffness lasting longer than one hour

• Reduced joint mobility and grip strength

• Fatigue and generalized malaise

• Low-grade fever in some patients

• Firm lumps under the skin (rheumatoid nodules) in longstanding disease

When Should You Consider Testing?

Testing is generally appropriate when joint symptoms persist for six weeks or longer, involve multiple joints, follow a symmetric pattern, or are accompanied by prolonged morning stiffness — particularly when a doctor is evaluating possible inflammatory arthritis rather than mechanical joint pain.

Why Tests Are Combined

No single test can confirm rheumatoid arthritis on its own. Anti-CCP and Rheumatoid Factor (RF) are antibody tests that support diagnosis, while CRP and ESR measure the degree of active inflammation rather than confirming the disease itself.

Some patients with RA test negative for RF (referred to as "seronegative" RA), which is why Anti-CCP — a more specific marker — is often tested alongside RF rather than in isolation.

Combining antibody testing with inflammatory markers gives your doctor both a diagnostic signal and a measure of current disease activity, which is valuable for both confirming RA and tracking response to treatment over time.

Tests Available at NPL

Most autoimmune antibody tests and inflammatory markers do not require fasting. However, if your doctor has ordered other tests at the same time — such as glucose or lipid testing — fasting may be required for those investigations. Please follow the preparation instructions provided by your doctor or NPL.

When to See a Doctor

• Joint pain, swelling, or stiffness lasting more than six weeks

• Symmetric involvement of multiple small joints (hands, wrists, feet)

• Morning stiffness lasting longer than one hour

• Joint symptoms accompanied by unexplained fatigue or low-grade fever

• Difficulty performing daily tasks due to joint pain or reduced grip strength

• Known RA with new or worsening symptoms despite treatment