The translation is correct: phlebs = blood vessel/vein and tomae = cut. So phlebotomie means to cut open a vein, to draw a substantial amount of blood (which was in former times supposed to help against all sorts if illnesses, but is basically not done today any more).
Maybe you mean "phlebologie" (translation: Phlebologie, Gefäßheilkunde) which is the name for a medical specialization concerning vein diseases.