I've counselled people with perceived mental + sexual issue when it comes to performance in bed.

Would recommend that if you could, rule out any physical factors before moving on to mental / behavioral factors. Therefore your blood test would be definitely helpful for your service providers to diagnose your potential issues.

Remember to to include any additional factors such as medications (finasteride / minoxidil / dutasteride); supplements (magnesium / iron / herbals) when you disclose to healthcare service providers.

It's easier to rule out objective findings rather than subjective first, while you are searching for your ideal counselor / therapist / psychiatrist.

Yeah, usually the patients that has potential ED, chances are its temporary (mental / behavioral) or due to other correlated chronic illnesses or metabolic dysfunctions. Once its ruled out then its easier to not only come to diagnosis but also recommend for further consultation with specialists.