What blood tests check for inflammatory arthritis in the knee?

The main tests and what they mean

• CRP and ESR: general markers of inflammation; raised in active inflammatory arthritis but also in infections and other illnesses
• Rheumatoid factor: positive in many people with rheumatoid arthritis, but also in some healthy people, especially older adults
• Anti-CCP antibodies: more specific for rheumatoid arthritis and can be positive early
• HLA-B27: a genetic marker linked with ankylosing spondylitis, reactive arthritis and some psoriatic arthritis
• Uric acid: often high in gout, although it can be normal during a flare
• Full blood count, kidney and liver function: help assess general health and guide safe treatment

Why normal results do not settle it

Many people with psoriatic or reactive arthritis have completely normal antibody tests, and some with early rheumatoid arthritis test negative at first. Inflammation markers can also be normal when only one knee is involved.

For this reason the examination, the pattern of joints and imaging carry as much weight as the blood results. A positive test without symptoms usually does not need treatment.

Joint fluid and imaging

When a knee is swollen, drawing fluid from it often gives more direct information than blood. The fluid's cell count shows whether the swelling is inflammatory, and it is checked for crystals and infection. Ultrasound or MRI can show thickened joint lining, and X-rays show any erosions or wear.

Getting the tests interpreted in Doha

Bring copies of any previous blood results to your appointment. At Aman Hospital Dr. Gelber puts the results together with the examination of the knee, arranges fluid analysis or imaging where helpful, and refers you to a rheumatologist when the picture points to an inflammatory condition that needs medical treatment.