Does diagnosis of erectile dysfunction involve embarrassing and invasive testing?

No. Most ED can be diagnosed with a professional asking appropriate questions, a detailed physical exam and routine blood work. Occasionally, i order an ultrasound of the penis which is a little uncomfortable.
No but depends on u. The diagnosis of erectile dysfunction is made by history. How embarrassed are you to tell your doctor that you're having an issue with attaining & sustaining an erection firm enough for intercourse? As part of a visit, we check vital signs which can be embarrassing but not too invasive. Physical exam is a bit more invasive. Blood tests are definitely invasive. But that's about all we need to do.