There are also tests in which a quantity of blood is withdrawn in order to tag it or to mix it with medicine, whereupon it is put back into the patient.
किंवा मग, रक्‍तातला एखादा घटक वेगळा करून शरीराच्या दुसऱ्‍या एका ठिकाणी त्याचा वापर केला जातो.