I was diagnosed with PMR and possible GCA in July 2024. My sed rate and CRP were both high and I had headaches in the area where GCA headaches can occur. I was immediately put on 60 mg. of Prednisone for the possible GCA. I had an order to get a bi-lateral temporal biopsy and got it on day 8 after my diagnosis. My rheumatologist and primary told me that after 14 days, the test may not be reliable due to my taking the high dose of pred. The biopsy came back negative, but with the caveat that it didn't necessarily indicate that I didn't have GCA. They may not have sampled an affected artery.