be beside yourself. C2 If you are beside yourself with a particular feeling or emotion, it is so strong that it makes you almost out of control: He was beside himself with grief when she died. (Definition of âbe beside yourselfâ from the Cambridge Advanced Learnerâs Dictionary & Thesaurus Â© Cambridge University Press)
Rheumatoid Factor Test. The rheumatoid factor is an antibody present in the blood of many patients with rheumatoid arthritis. Doctors measure the level of rheumatoid factor by performing a blood test. A positive rheumatoid factor test means that the patientâs level of rheumatoid factor in their blood is considered high.
Rheumatoid Factor (RF). Guide. A rheumatoid factor (RF) blood test measures the amount of the RF antibody present in the blood. Normally, antibodies are produced by the immune system to help destroy and eliminate invading bacteria and viruses that can cause disease. But the RF antibody can attach to normal body tissue, resulting in damage. A high level of rheumatoid factor can be caused by several autoimmune diseases (including rheumatoid arthritis) and some infections. Occasionally an elevated level of RF is present in healthy people. The amount of rheumatoid factor in blood can be measured in two ways: 1  Agglutination tests. 2  One test method mixes blood with tiny rubber (latex) beads that are covered with human antibodies.