Most of the time the pain from a needle stick is short-lived, but not always. What causes pain in the arm days after a blood test? Find out more about needle stick pain - and what it means if it doesn't go away.
The Causes of Pain in Arm Days after Blood Test
Getting blood drawn may be painful but only for a few minutes in most cases. Once the needle is removed from the vein – it’s sweet relief. On the other hand, in a small number of cases the pain of venipuncture can persist even after the needle is removed, and you’ve returned home. What causes pain in the arm days after a blood test?
It Could Be a Hematoma
One cause of pain is a hematoma. A hematoma is a collection of blood that forms outside the vein. During a blood draw when the needle pierces the vein, it can become temporarily damaged causing blood to leak out into the tissue. The leaked blood forms a pocket of blood, which can be painful. It’s not uncommon for the area around a hematoma to turn red or blue, and the surrounding tissue to become swollen.
Fortunately, the body gradually reabsorbs the displaced blood cells, and the hematoma slowly resolves – although it can look pretty ugly in the meantime. A hematoma is quite easy to see and is a very visible cause of pain in the arm days after a blood test. Doctors usually recommend that people treat hematomas by applying ice packs, elevating the arm, and taking anti-inflammatory medications for the pain. Hematomas usually resolve in five to seven days.
In rare cases, a hematoma can become infected, causing worsening arm pain and redness. This type of skin infection or cellulitis needs immediate antibiotic treatment.
Another Cause of Pain: Nerve Injury
During a blood test, the phlebotomist withdraws blood from a vein in the arm using a needle. Unfortunately, nerves are in close proximity to the major blood vessels in the arm. Sometimes during a blood draw, the needle hits a nerve. This can cause not only pain, but numbness and tingling in the arm or hand.
If the phlebotomist hits a large nerve, a person may feel a brief, shock-like pain as the needle nicks the nerve. Fortunately, most venipuncture nerve injuries heal, but it may take weeks or months for the arm discomfort and nerve symptoms to completely go away. In rare cases, the nerve damage can be permanent. Sometimes, swelling that comes from a hematoma causes pain, numbness, and tingling by putting pressure on a nerve. This usually subsides once the hematoma has resolved.
Not All Arm Pain after a Blood Test is Serious
It’s normal to experience a little discomfort and soreness for a day after a blood test, but arm pain that lasts longer is less common. When it occurs, the best course of action is to see a doctor and make sure there’s no sign of nerve damage, hematoma, or infection at the site of the needle stick. Most needle sticks hurt, but, fortunately, they don’t cause lasting damage.
Journal of Family Practice, May, 1992 by Harold J. Galena.
Merck Manual. Eighteenth edition. 2006.