What Are the Side Effects of Having Blood Drawn?

The side effects of having blood drawn are typically small and not life threatening, but may be uncomfortable and include bruising, swelling at the injection site, dizziness and lightheadedness, reports ABC News. For people who are on blood-thinning medication, a pressure bandage may be necessary to avoid the worst potential side effects, according to ABC News.

The feelings of dizziness and lightheadedness should disappear within hours. Any bruising or swelling that does happen should disappear within days, according to One Medical.

Some people experience nervousness and anxiety before they get their blood drawn. For these people, it can be helpful to know what is happening during the procedure. It can also be helpful to chat with the phlebotomist during the blood draw states One Medical. If a person knows that they faint during blood draws or have a needle phobia, then the phlebotomist should be notified, says One Medical.

The blood draw procedure is simple and often takes no more than 15 minutes. The first step involves the phlebotomist finding the best place to draw the blood writes One Medical. The phlebotomist will do this by feeling the veins in the arm with their fingers. Then the phlebotomist will use an alcohol pad to clean the patch of skin where the needle will be entering the vein and tie a tourniquet around the arm, according to One Medical. The needle will then be inserted and the blood drawn.