"No blood test can definitively prove or rule out a diagnosis of rheumatoid arthritis, but several tests can show indications of the condition.

Some of the main blood tests used include:

erythrocyte sedimentation rate (ESR) – which can help assess levels of inflammation in the body

C-reactive protein (CRP) – another test that can help measure inflammation levels

full blood count – this test can be used to help rule out other possible causes of your symptoms as well as provide an indicator your general health

The full blood count test can also be used to check if you have anaemia. Anaemia means the blood is unable to carry enough oxygen because of a lack of blood cells.

Anaemia is common in people with rheumatoid arthritis, although having anaemia does not prove you have rheumatoid arthritis.

Rheumatoid factor and anti-CCP antibodies

One blood test measures levels of rheumatoid factors in the blood. Rheumatoid factors are proteins that the immune system produces when it attacks health tissue.

About half of all people with rheumatoid arthritis have high levels of rheumatoid factors in their blood when the disease starts, but about 1 in 20 people without rheumatoid arthritis also test positive.

A related blood test known as anti-cyclic citrullinated peptide (anti-CCP) test is also available. Anti-CCPs are antibodies also produced by the immune system.

People who test positive for anti-CCP are very likely to develop rheumatoid arthritis, but not everybody with rheumatoid arthritis has this antibody.

Those who test positive for both rheumatoid factor and anti-CCP may be more likely to have severe rheumatoid arthritis requiring higher levels of treatment.

(...)" from https://www.nhs.uk/conditions/rheumatoid-arthri...

I have RA, and Psoriatic Arthritis, and Osteoporosis, and Sjodrens Disease that I swear feels like it has an effect on all three types.

Thank you for the information.

I have RA ......