A high SED rate might accompany many conditions like Parkinsons, cancer, or autoimmune disorders - it's a broad quantifiable test of how severe your inflammation is regardless of cause. When it causes concern, it's typically off the charts. "Normal" SED rate is about 0-15, while an out of control systemic condition can drive it far north of double or triple the high reference point (not just slightly over).
The SED rate doesn't identify its cause, so ANA and CRP can be ordered after a high SED rate (along with tests such as CBC, urinalysis, etc that would indicate other possible causes). CRP and ANA tests are pretty specific to autoimmune diseases.
ANA is most often associated with SLE (lupus). Not all AI diseases have positive ANA screen, and even in SLE once it's in a managed state both SED and ANA titer would ideally be back within spec.
I'd be curious (if you do regular blood work) do you have a SED rate within spec but an ANA titer out of spec? Or "just" a positive ANA screen test?
Time to see a rheumatologist