After undergoing lymph node removal as a part of breast cancer treatment, some people worry that getting their blood drawn can be risky. While many doctors recommend avoiding blood draws on the same side you had nodes removed from, new research shows that this procedure may not be as likely to cause problems as health experts previously thought.

If you have had lymph nodes removed or have undergone radiation therapy to the armpit — or if you may undergo one of these procedures in the future — read on to discover what you should know about getting blood draws.

When Might You Need Blood Draws?

Health care providers order blood draws — also called venipunctures or phlebotomies — when they need a small sample of blood for testing. This usually entails inserting a thin needle into an arm vein.

Your doctor may need to collect a blood sample during the course of breast cancer treatment for multiple reasons, including:

• Performing a complete blood count (CBC) — a test that measures the numbers of each blood cell type — to determine if cancer treatments are causing additional problems like anemia (low levels of red blood cells)
• Measuring substances that show how well your liver or kidneys are working to make sure that you are healthy enough to receive treatments like chemotherapy
• Assessing levels of proteins called tumor markers that your cancer cells may produce, which can indicate whether treatments are working

Blood draws are also frequently conducted as part of your regular physical exam. Blood tests can help your health care team better understand multiple aspects of your health.

Risks of Blood Draws

Blood draws can lead to side effects for anyone, regardless of their cancer status. These side effects include mild bleeding, bruising, and pain.

It’s also possible — but extremely unlikely — to develop an infection from having your blood drawn. The risk may be slightly higher for people who are immunocompromised. However, to protect both themselves and the people they care for, health care professionals take abundant precautions to prevent the risk of infection, including:

• Washing their hands frequently
• Wearing gloves and other types of personal protective equipment
• Using needles only once
• Disinfecting surfaces
• Cleaning the site from which blood will be drawn with appropriate disinfectant

Are Blood Draws Safe Following Lymph Node Removal?

Lymph nodes normally help drain fluid out of your tissues. People who have had surgery to remove their underarm lymph nodes may have a higher risk of developing lymphedema — fluid buildup in the affected arm that may lead to pain or swelling. Depending on the severity of lymphedema, people may also experience numbness and tingling, changes in skin texture or appearance, and changes in the fit of clothes or jewelry on the affected arm.

Some doctors used to caution against getting blood drawn from an arm that’s undergone lymph node removal surgery. This warning was based on one small study from nearly 20 years ago, in which researchers reported that participants were more likely to develop lymphedema when blood was drawn from the same arm from which their lymph nodes had been removed.

However, a larger, more recent study reported that people who had undergone lymph node removal were not more likely to develop lymphedema after blood draws — even when the blood was drawn from the affected arm. Additionally, there isn’t much additional research that supports the assertion that blood draws may trigger lymphedema.

It’s important to note that cellulitis — a common bacterial skin infection — may raise your risk of developing lymphedema. As noted, infections from blood draws are very rare, but they may trigger lymphedema if they occur.

There are a number of ways to reduce the risks of lymphedema and manage its symptoms. Some people found that altering their activities, wearing different clothing, and engaging in massage or physical therapy to be helpful.

Blood Draw Recommendations

Some health experts recommend getting blood drawn from the opposite side that was treated for breast cancer, although others say it doesn’t matter. Additionally, if it’s not possible to draw blood from the opposite arm, most experts say it’s safe to use the affected arm.

Your risk of developing lymphedema is highest during the first three years after lymph node surgery. After that, your risk drops, but you may still develop lymphedema later in your life. Therefore, you may want to consider using the unaffected arm for blood draws indefinitely.

Where Do You Draw Blood When You Have a Double Mastectomy?

For people who’ve had lymph nodes removed on both sides of the body, health experts often recommend they have blood drawn from either arm or talk to their doctor about which options are best. In some cases, doctors may recommend drawing blood from other veins, such as those in the foot. However, not all providers like to do this, because blood draws from the foot tend to be less convenient, more painful, and more likely to lead to blood clots.

Members of MyBCTeam who’ve had lymph nodes removed on both sides or have undergone a double mastectomy have discussed trying to get blood drawn from other locations. “No one seems to know how to draw blood from a foot,” said one member, noting that their provider recommended calling ahead to make sure they received necessary accommodations. “I need someone with experience and not students on duty that day.”

Another member commented, “The phlebotomist pricks my finger just like for those who have diabetes.”

Tips for Managing Blood Draws

If you have to get blood drawn from your affected arm, consider asking the nurse or phlebotomist if they can do so without a tourniquet — having your arm constricted or your blood flow decreased may lead to lymphedema. You may also want to see if they can use a needle that’s thinner than usual. “I have good veins in my arms, so the nurse is able to use a small needle without a tourniquet,” reported one member.

You may have to go to certain locations for your blood draw to receive these types of special procedures. “I only have blood drawn at an oncologist’s office or lab,” one member wrote. “Medical assistants in a doctor’s office are just not comfortable or experienced doing it.”

If you want to avoid getting blood draws on your affected side, or if your doctor recommends doing so, you might consider getting a medical alert bracelet. This will tell providers not to draw blood from or start IV lines in that arm in case of emergency. You may also want to ask your doctor whether they can put this information in your chart.

One member, who had lymph nodes removed on both sides, wrote, “I’ll have a bracelet for the arm that had most of the nodes taken out, so they only touch one arm — the one that had the fewest nodes taken out — in case of an emergency.”

You can also protect against lymphedema by avoiding injections, IVs, or blood pressure readings in the affected arm. Additionally, watch for signs of infection after blood draws or other medical procedures. Tell your doctor right away if you notice discoloration, warmth, or swelling in an area of your skin.

Connecting With Others

On MyBCTeam — the social network for people with breast cancer and their loved ones — more than 64,000 members come together to ask questions, give advice, and share their stories with others who understand life with breast cancer.

Have you had lymph nodes removed from one or both sides? How do you handle blood draws? Share your experiences in the comments below, or start a conversation by posting on your Activities page.