Hey all. I was diagnosed with Ankylosing Spondylitis (AS) in July 2021 after experiencing hallmark symptoms (including bilateral sacroiliitis) since November 2020. I have always found it curious that I am HLA-B27 negative with blood work that shows highly elevated rheumatoid factor (RF) and normal results for the C-reactive protein. I have read that those with AS are more likely to be HLA-B27 positive with normal RF results and high C-reactive protein results; the exact opposite. Is this the case for anyone else as well? I don’t doubt that I have AS, but I do wonder if I am an unusual case or if studies could be more complete.