Suetex. I had a muscle biopsy of my quadriceps in 2019 at Mayo Clinic in Scottsdale. After a decade of progressive muscle weakness, pain and atrophy, it was the only test that provided an answer. I had neuromuscular toxicity from Plaquenil that I had taken for 25 years! A muscle biopsy is a valuable test when the diagnosis is uncertain or you are not responding clinically as expected. It was not bad but was uncomfortable afterwards as any surgical site does. The answer was well worth any discomfort I experienced.