I'm negative and remain undiagnosed, despite a "chronic sacroiliitis" diagnosis at 27 and 20+ years of chronic inflammatory back pain that meets the ASAS diagnostic criteria for Ax-SpA and certainly for Nr-AxSpa. The first rheumatologist told me maybe I had dystonia (nope - symptoms aren't even close to matching), the second said it couldn't be AS because I was seronegative and not a man (eye roll to medical misogyny), and the third diagnosed degenerative disc disease without reviewing any of my recent MRIs which show no disc degeneration whatsoever. In fact, another physician who reviewed my imaging said my discs look like someone in their 20s, not their 50s. Depending on how well your rheumatologist understands the spectrum of spondyloarthropothies, being seronegative can sometimes be a real road block. It certainly has been for me!