I am “seronegative” according to my RF factor results/doctor. The Vectra test has been a most accurate measurement of the inflammation, it puts you into categories of disease activity like mild to moderate or moderate to severe for example. Sometimes I will know by the way my joints etc feel that I’m flaring or not responding to RA meds and regular inflammation blood tests don’t show how bad I really feel, but the Vectra always reflects it , in 4 years since being diagnosed I’ve not made it below the moderate to severe grouping. On the downside some insurance companies won’t pay anything for it.