Final answer:
Step 3 in the treatment termination/returning blood process is Returning the blood sample to the patient, which involves infusing the treated or filtered blood back into the patient's circulation after collection and analysis.
Step-by-step explanation:
The question at hand pertains to a medical procedure, specifically the steps involved in blood treatment and the subsequent return of blood to a patient. When considering the process like hemodialysis or any treatment involving the external processing of the blood, step 3 in the treatment termination/returning blood process typically refers to Returning the blood sample to the patient. This step comes after the blood has been collected and analyzed, and having completed any requisite treatments or removal of waste products, the cleansed or treated blood is then safely infused back into the patient's circulation.
For example, as depicted in Figure 11.39.2 and Figure 19.5.4, during dialysis a patient's blood is filtered to remove waste products, and after such filtering, the clean blood is returned to the patient's body.