Rheumatoid factor or RF is a genetic marker protein that is occasionally (<5%) present in normal persons as well as in patients with rheumatoid arthritis 9~80%) and their family members (~30-50%).
This protein is NOT directly related to disease activity. In simple terms, a patient may be in complete remission yet, its quantity in the blood may remain high. This is due to gene dose - some have high dose while some have low dose. Putting it in simple language, you should NOT worry about RF, it is NOT related to disease activity. Your clinical condition is the best parameter to say whether you have shown a good response or not. Add to that another simple test called ESR (lower than 28 mm in the first hour is considered normal, higher than that indicates active disease, higher the ESR more disease activity) and you get the best measures to determine whether you have responded satisfactorily.