I had a karyotype of the blood done at Cedars Sinai - they did a good job. Any doctor could order this and insurance covers this. Karyotype will show things like XX, XY, XXY, XXYY, XXX etc. I had a regular DNA analysis done of blood and two skin types - the regular DNA of the blood showed the chromosomes, skin is more tricky. Any DNA lab can run blood, no doctor needs to be involved and it's not that expensive ($300-$1200). However, if your XXY or some other variant, that may not show up on a regular DNA test. DNA will do good on XX or XY only. I'm still looking for a good laboratory to redo the skin as there were issues and good lab equals REALLY expensive - like new car expensive. Insurance doesn't cover that.
In the end, I'm me. It's up to you on how important it is. I'm looking for health reasons, I'm transitioning to a woman because that's what I am.