There is no straightforward test for diagnosing rheumatoid arthritis (RA). A doctor with make a diagnosis based on the symptoms you describe and by carrying out a physical examination. Bloods tests or x-rays can help confirm the diagnosis.

Explaining your symptoms

Making a diagnosis of RA is not as straightforward as you might think. The symptoms vary from person to person and can be similar to those of other conditions such as fibromyalgia, gout etc.

Symptoms can come and go, depending on the degree of inflammation of the tissue. When tissue inflammation subsides, the disease is inactive (in remission). When the disease becomes active again (relapse), symptoms return and individuals may experience ‘flare-ups’. During flares, joints frequently become red, swollen, painful, and tender.

Symptoms should be described, not only based on how you are feeling the day you visit the doctor, but also over a period of time. This helps in assessing the pattern of your disease and in making a diagnosis.

Rheumatoid arthritis differs from other forms of arthritis in that multiple joints are inflamed in a symmetrical pattern. It is common that in RA if the knuckles in your right hand are inflamed, the knuckles in the left hand will also be affected.

Other joints that might be affected include the elbows, jaw, neck, feet, ankles, knees and hips. Your doctor will take a note of which joints have been affected to help in the diagnosis.

Certain symptoms should prompt you to make an early appointment to visit your doctor.

• Morning stiffness in the joints that lasts longer than one hour.
• Pain and swelling in three or more joints at the same time.
• Pain in a joint all night long.
• Pain in the same joints on both sides of your body.
• At least one swollen joint in the wrist, hand or finger joints.

Beyond the joints

As rheumatoid arthritis is a systemic disease (affects the body as a whole) your GP may look for other clues to make a diagnosis. Around 20-25% of people with rheumatoid arthritis will have firm lumps under the skin at pressure points of the body such as the elbow, hands or feet. These lumps are called rheumatoid nodules.

Sometimes other organs can be affected. Inflammation of the tear glands can cause the eyes to become dry and irritable.

Your tiredness may be due to reduced levels of red blood cells in your body – known as anaemia – which is very common in people with rheumatoid arthritis.

Hospital tests

In addition, to taking a careful history and a physical examination, there are some tests that your doctor may carry out to confirm the diagnosis. These include laboratory tests (blood and joint tests) and imaging techniques such as x-rays.

A doctor may use a combination of tests to make the diagnosis.

Presence of anaemia

Anaemia affects about eight out of 10 people with rheumatoid arthritis. To detect anaemia, a full blood test is carried out that looks at the number, size and shape of red blood cells.

Tests may also be used to detect changes in the blood, which are produced by inflammation.

Erythrocyte sedimentation rate test (ESR)

An erythrocyte sedimentation rate test (ESR) is sometimes used to test the degree of inflammation in your body. If you are healthy, the sedimentation rate is normally low.

Plasma viscosity (PV) test

The plasma viscosity test is a recent type of diagnostic procedure.

C-reactive protein (CRP)

C-reactive protein test is similar to the ESR test. This will show a high value if inflammation is present.

Rheumatoid factor

The ‘rheumatoid factor’ is another blood protein, which may be present in those with RA. Over two-thirds of people with RA will have high rheumatoid factor. Unfortunately, its presence does not make the diagnosis certain – some people who do not have rheumatoid arthritis have high rheumatoid factor including some healthy people and people with autoimmune diseases.

X-rays

X-rays can show damage to the joints caused by inflammation in RA. Your feet may be x-rayed in hospital as changes caused by rheumatoid arthritis often appear in the feet before they appear in other joints.

Magnetic resonance imaging (MRI) and ultrasound scanning

Magnetic resonance imaging (MRI) and ultrasound scanning can help make an early diagnosis.

Ultrasound is a safe technique that involves exposing part of the body to high-frequency sound waves to produce real-time pictures of the inside of the body.

Magnetic resonance imaging (MRI) is a painless and safe diagnostic procedure that uses a powerful magnet and radio waves to produce detailed images of the body’s organs and structures, without the use of x-rays or other radiation.

Both MRI and ultrasound imaging will show bone and soft tissue damage in the early stages of rheumatoid arthritis.

Joint fluid analysis

The synovial fluid within a joint can be extracted from a joint using a needle and syringe, and analysed in the laboratory. Cloudy joint fluid may be abnormal and may be a result of inflammation or an infection.