Many patients have bruising at the site of blood sampling due to the following reasons: 1. After blood sampling, the patient’s local pressure is not good enough to cause blood to seep out and cause local bruising. 2. The needle used by the patient to collect blood is thick, and when the needle is pulled out of the patient’s blood vessels, there will be a needle eye left in the blood vessels. If the pressure time is not enough, the blood will seep under the skin along the slit of the needle eye and become bruised. When bruising occurs after a patient has had blood drawn, local ice packs can be used to reduce blood leakage by using ice packs to constrict the blood vessels, and hot packs can be considered after 48 hours to promote dissipation of the bruising. If the local bruising is increasing in extent, it is recommended to go to the hospital for treatment in a timely manner.