Risks
There is very little chance of problems from
having blood drawn from a vein. You may get a small bruise at the site. You can
lower your chance of bruising by keeping pressure on the site for several
minutes.
In rare cases, the vein may become swollen after the
blood sample is taken. This problem is called phlebitis. You can use a warm
compress several times a day to treat this.
Ongoing bleeding can
be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin),
and other blood-thinning medicines can make bleeding more likely. If you have
bleeding or clotting problems, or if you take blood-thinning medicine, tell the
doctor before your blood is drawn.