I was on a tazorac study at ucla, but it was topical. Is your son taking an oral form of tazorac(tazarotene)? I never had to have my blood drawn when on this study, it only lasted 3 months though. I have been on accutane and always had to have cbc chem panel done when on retinoids. If your son is taking any kind of retinoid, tazorac included, he should be having his blood checked. I don't know how this could slip your derms mind. Any doctor should be able to look at his blood test results and tell you if his levels are ok.