My husband recently went to a rheumatologist upon recommendation of his orthopedic doctor. He is 34 and has had low low back pain for 2 years. His ortho performed an mri and couldnt find any issues. The radiologist suggested a slight bulge in his right SI/L5. After going to the rheumatologist, we have received a suggested diagnosis of Ankylosing Spondylitis, despite the fact that he is HLA-B27 negative with normal CRP and ESR. The rheumatologist stated that he did have narrowing of his SI joint (no issues with spine, hips, or knees xrays) and was basing his diagnosis on that. He wants to start my husband on TNF inhibitors. I am trying to get a second opinion, but it takes months to get into another rheumatologist as a new patient. If it truely is AS, I know that starting treatment early is the key... And I don t want to delay treatment that could prevent additional fusion. Could this just be arthritis in his SI joint, or does the narrowing definitely mean AS?