I am a doctor I was wondering if there is a need for making netilat yadaaim if I am in contact with blood, even is I have gloves? Does it change anything if it comes from a covered part of the body or not?

Nishmat Avraham (Orach Chayyim 4 19) writes that netilat yadayim is required only if blood was drawn for therapeutic purposes -eg. the patient needed his blood thinned. Taking blood for diagnostic purposes or donating blood to a blood bank does not require netilat yadayim.