Bruise after a blood draw: should you worry?

Every time you draw your blood, you run a 293-per-million chance of a serious injury. Like a blown vein, or nerve damage.

However, the chance of getting a mild, harmless bruise after a blood draw is way higher. So how do you know if a bruise is a cause for concern?

We're Loop Medical. We designed the bruise- and needle-free blood collection device, Onflow. In this article, we'll tell you what to do with a bruise after a blood draw. (More about Onflow at the end)

But first, let’s clear out some misconceptions.

What does a bruise after a blood draw mean?

A bruise after drawing blood means capillaries under the skin were damaged. In other words, you’re bleeding internally.

People often confuse two terms: hematoma and ecchymosis:

• A hematoma is an internal bruise causing blood swelling under the skin
• Ecchymosis is the discoloration resulting from hematoma

The bruise you see on the surface is a discoloration from the blood trapped under the skin. Over time, it changes color and fades until it disappears.

Bruising after a blood draw is a common side effect and is usually harmless.

Another misconception is that a bruise means a contamination from the needle. Although infections could happen, a bruise is not an immediate sign. (More on infections later).

Why do you get a bruise after a blood draw?

• Blown veins. The needle might break the wall of blood vessels. This is the most common cause of hematoma bleeding
• Insufficient pressure. on the needle site. If the person drawing the blood doesn’t press on the puncture site once the needle is removed, blood can leak into the surrounding tissues, causing a bruise
• Anticoagulant medications. Drugs like aspirin, warfarin, and clopidogrel reduce blood clotting. Taking them makes you more prone to bruising
• Genetics. Some people naturally have fragile blood vessels, making them more prone to bruising after a blood draw
• Less common causes include: Liver disease, certain medications, and vitamin deficiencies, may also increase the chance of bruising

How long does a needle bruise last?

It takes around two weeks for a needle bruise to go away. This can vary depending on the individual and the severity of the bruise. Here is a timeline of what to expect:

• First two days. This is when it hurts the most. The bruise is red or purplish. Fresh, oxygen-rich blood pools under the skin.
• First week. The bruise is most visible now. The blood loses oxygen and the bruise may turn bluish-purple or even black.
• Ten days in. The bruise becomes yellow or green. The body breaks hemoglobin and releases the colorful biliverdin and bilirubin.
• Two weeks later. The patch turns yellow-brown. The body reabsorbs the blood and the bruise fades away.

When to worry about a bruise after a blood draw?

Needles can sometimes cause irreversible damage. Blown veins and damaged nerves are serious injuries. But those chances are low. In most cases, bruises after a blood draw are not a cause for concern.

Seek medical attention if:

• You feel severe discomfort
• The pain increases over time
• The bruise is large and unexplainable
• You grow a lump on or near the area where blood was drawn
• You have a history of excess bleeding or blood clotting disorders

If none of the above applies, here are a few other things to look for:

• Size and color of the bruise. If the bruise is larger than a quarter or if it's accompanied by significant pain, swelling, or redness, it's a good idea to contact your healthcare provider, as these may be signs of a more serious issue
• Bruising in unusual places. If you notice bruising in areas other than the puncture site, such as your hands or feet, it could be a sign of a bleeding disorder, and you should seek medical attention
• Prolonged bleeding. If you experience prolonged bleeding after a blood draw, it could be a sign of a clotting disorder, and you should contact your healthcare provider
• Sudden bruising. If you suddenly begin bruising after starting a new medication or have acute pain or inflammation at the blood draw area, it's also a good idea to consult your doctor

Tips to prevent bruising after a blood draw

• Avoid blood-thinning medications and over-the-counter NSAIDs a day before and after your appointment
• Don't lift anything heavy using the punctured arm. You might displace the blood clot
• Don’t wear tight clothes. They prevent blood circulation, pressure the veins, and lead to a larger bruise
• Apply pressure. After the needle is removed, press to the puncture site for a few minutes to help prevent bruising
• Ice the area. Put an ice pack on the puncture site for 10-15 minutes. This reduces swelling and minimizes the chance of bruising
• Avoid intense activity. You risk bruising by using your punctured arm. Take it easy for a day or two

Frequently asked questions

Can you get an infection from a needle?

Yes, you can get an infection from a needle. The most common infections from a needle injury are the human immunodeficiency virus (HIV), hepatitis B (HBV), and hepatitis C (HCV).

What percentage of needle stick injuries are infected?

The chances of catching a disease from a single needle stick are usually very low. But they can vary depending on the disease and the conditions.

For example, about 1 out of 300 healthcare workers accidentally stuck with a needle from someone with HIV get infected. But the odds can be as high as nearly 1 in 3 for hepatitis B if the worker hasn’t been vaccinated for it.

In addition to HIV and hepatitis, needlestick injuries can also pass on other kinds of pathogens. This includes Rocky Mountain spotted fever, varicella-zoster virus (which causes chickenpox and shingles), and Epstein-Barr (a type of herpes virus).

What are the symptoms of a needle infection?

Pathogens induce different symptoms. Seek help if you feel any unusual redness, warmth, swelling, or discoloration.

Later infection symptoms also include:?

• Fever. An infection can cause a fever, which is a sign that the body is fighting off the infection
• Nausea and vague abdominal pain. In the case of a hepatitis B infection, some individuals may experience jaundice, fever, nausea, and vague abdominal pain. These symptoms usually subside in 4 to 8 weeks
• Swelling of the lymph nodes. The lymph nodes near the injection site may become swollen
• Sweating and violent illness. In some cases, individuals may experience sweating and a sudden onset of violent illness

Needle-free (and bruise-free) blood collection

At Loop Medical, we created the needle-free blood collection device: Onflow.

Onflow is:

• Safe

• Quick
• Painless
• Collects enough blood for routine lab tests
• Easy to use – even for children and seniors

In our 2022 clinical study, Onflow:

• Achieved a 97% success rate
• Was 99% compatible with standard lab analyzers
• Was labeled as having “little to no pain” by 91% of participants (here’s what the users actually said)

By 2024, we’ll help make wellness testing a lot easier (and less painful).

Interested in a pilot using the painless Onflow? Get in touch today!

Conclusion

In most cases, needle injuries are harmless. But look out for signs and take preventive measures to protect yourself.

Don’t let needle anxiety prevent you from getting routine testing. Stay up to date with your well-being and how the medications you’re taking can affect your body.

Expect the bruise to go away in two weeks.

Can needle anxiety link to shorter lifespans? Here’s what we know about the fear of needles.