The doctor should specify to the lab tech it is to be a venous draw.  Try a clinic with an experienced pediatric endo if there is no lab on the site you go to or you are having communication problems with the lab techs.  It is difficult to make med personnel listen to us moms as they know we’re not doctors(most of us) & will disregard anything we try to tell them.  Most of us become more educated about CAH with the birth of our children because we have to ...most pediatricians don’t even see this medical condition & we have to bring in booklets & referrals from endo’s to educate them.  I wish there was more knowledge in the medical community about this condition, until then & more research money, all our children have is us.   You can call Nemours children’s clinic in Jacksonville FL (a teaching clinic)  if you need help or have questions.  Our ped endo was Dr. Nelly Mauras...our daughter also had surgery there to avoid going into a crisis during surgery.  Much luck & love.  I wish there was more help out there for our children.