Bruising after drawing blood may occur for various reasons, including liver disease, certain medications, and vitamin deficiencies. Some people may bruise after a blood draw more easily than others.

Bruising is not an uncommon occurrence, but it can be uncomfortable.

In this article, we discuss why bruises may appear after a blood draw, when to see a doctor, and how to reduce the likelihood of a bruise occurring.

a person showing bruising on their arm after a blood drawShare on Pinterest
It is common for bruising to occur after a blood draw.

When a healthcare professional draws blood, they insert a small, hollow needle through the skin to access a vein. This procedure temporarily damages the blood vessel wall and the outermost layer of skin.

Bruising occurs when blood from the damaged vein leaks out and settles under the skin.

Some people may bruise more easily than others.

Some causes of easy bruising include:

According to the World Health Organization (WHO), bruising after a blood draw typically heals quickly. However, if the bruise is large, it may take 2–3 weeks to fade and disappear.

A person should call their doctor if they experience any of the following symptoms:

  • the hand becoming discolored
  • numbness or tingling in the arm or hand that does not go away within a few hours
  • worsening redness and inflammation at the puncture site
  • severe pain at the puncture site
  • swelling that worsens instead of improving

If a person is unsure whether their symptoms are typical, they should call a doctor or seek medical attention.

A person can take several steps to reduce the chance of a bruise occurring.

These include:

  • Asking for a small needle: The WHO recommend using butterfly or 22-gauge needles for blood draws in the elderly.
  • Applying pressure: Apply firm pressure to the puncture site after the removal of the needle, and keep the protective bandage on for at least 6 hours afterward.
  • Avoiding strenuous activity: A person should not lift heavy objects immediately after a blood draw.
  • Refraining from wearing tight clothing: Tight clothing may prevent the blood from circulating and place extra pressure on the veins, leading to a larger bruise.
  • Applying a cold compress: Doing this may reduce discomfort.

A bruise may appear to spread out in shape and size as it heals. Over time, it may change color from blue-black to green and then to yellow before fading.

To relieve any discomfort, a person can try:

  • Taking pain relievers: A person can take acetaminophen, but they should avoid ibuprofen and aspirin for 24 hours after the blood draw.
  • Applying a cold compress: A cold compress may help relieve pain.
  • Remaining hydrated: Drinking plenty of water and eating a small snack after a blood draw can help a person maintain their energy.

Bruising after a blood draw is common and not typically a cause for concern. However, if a person does experience severe discomfort, they should seek medical attention.

Taking some preventive steps, such as applying pressure to the puncture site and refraining from lifting heavy objects, can help reduce the chance of a bruise appearing.