a) come stai ? b) stai bene ? c) come va la tua salute ? (only when you know somebody is recovering from an illness; it is ok towards a very old person) /Sanita`/ is never is used in a personal context, as it means the establishment related to public health, like /Ministero della Sanita`/; asking somebody about his / sanita` / is completely misleading. /salute/ has also a non-personal meaning, like in : / la salute dei giovani e` a rischio per l'abuso di alcool / . / stare in [buona] salute / : to be in good health (/buona/ may be implicit)

Come va la sanità? Come va la salute ?