Final answer:
In case of exposure to a patient's blood, you should remove and bag the affected clothing for later washing, adhering to biohazard safety protocols and standard precautions.
Step-by-step explanation:
If you accidently get a patient's blood on your uniform during the treatment of a multisystem trauma patient, the correct action to take is to remove the affected clothing, bag it, and label it for later washing. This is to ensure that any potential pathogens in the blood do not pose a risk to you or to others. After removing the contaminated clothing, make sure to follow all the necessary biohazard safety protocols for handling and laundering such items. Place the bagged clothing in a designated area for contaminated laundry, and ensure you wash yourself thoroughly too, following standard precautions to prevent the spread of infectious agents.