Ports and the Possibility of Blood Draws

Why They're Used and Their Benefits

Having a special vascular access device (VAD) called a port-a-cath (port) allows chemotherapy to be administered safely. A port is a device implanted under the skin to give access to a large vein. It can be used to deliver chemotherapies that are too dangerous to give through small veins. The port can also be used for blood draws, other intravenous (IV) medications, and special imaging tests like CT (computed tomography) scans or PET (positron-emission tomography) scans.

This article explains what ports are, how they're used, and their potential benefits.

Senior Adult Man Cancer Outpatient During Chemotherapy IV Infusion
Willowpix / Getty Images

What Is a Port?

A port is a device that is surgically placed under the skin on either side of the chest, just below the collar bone. The port can also be placed in a different body area depending on the type of cancer and the person's medical condition. The procedure is done in the hospital, and most people go home the same day.

The port is made of two parts: the portal and the catheter. The portal is a small, heart-shaped drum. The top of the drum is made of self-sealing silicone so a Huber needle can puncture it. The remainder of the drum is plastic.

Some people may have a port with two portals or drums. Although completely under the skin, the portal will appear as a small bump on the chest.

The catheter is a thin plastic tube attached to the bottom of the portal. It's a few inches long and is surgically threaded into a large vein in the chest. Commonly used veins are the jugular, subclavian, or superior vena cava.

The port allows for the safe and easy delivery of medications, as well as the withdrawal of blood. There are no tubes or catheters outside the body when the port is not used. Once the surgical site is healed, swimming, bathing, and showering are allowed.

Who Gets Ports?

You and your oncologist (cancer doctor) will decide together whether you need a port. Factors to consider are:

  • Type of cancer
  • Type of chemotherapy
  • Frequency of chemotherapy
  • Length of cancer treatment
  • Condition of the veins in your arms

Not everyone who receives cancer treatment needs a port. Some cancer medications are safe to infuse into the veins of your arms. Your oncology nurse will assess the veins in your arms to determine if you need a port.

Benefits

The biggest benefit of a port is safety. Making sure chemotherapy is being administered in the safest way is reassuring for you and your oncology team.

Ports are also easy to use. There is no difficulty trying to find a vein. If chemotherapy is given daily or frequent blood draws are required, the Huber needle can be left in, decreasing the number of venous punctures you may need. A clear dressing is placed over the Huber needle to protect it while it's left in place.

In addition, the port device can remain in the body for many years, making follow-up imaging and blood work easy. Clinical guidelines need to be followed for managing and using infusion ports.

How Is the Port Used?

Before the port is accessed (punctured), a nurse will clean the skin above and around the port site. Cleaning the skin with an alcohol solution helps decrease infections.

The nurse will wear a mask during this procedure and use sterile supplies that are free from microorganisms. You shouldn't cough or breathe on your skin during this process. Turning your head to the opposite side is helpful.

Once your skin is dry:

  • The nurse will use a Huber needle to puncture your skin, gently pushing it through the silicone port device.
  • The Huber needle has tubing connected to it that remains outside the body during the infusion. A clear dressing is placed over the needle to keep it clean and anchored to the chest wall.
  • Next, a syringe is attached to the end of the tubing to aspirate (remove) blood from the port. This indicates the port is working. Lab tubes can be connected to the tubing for an easy blood draw.
  • The nurse will then flush the tubing with a syringe of normal saline, rinsing the blood from the tubing and the port device. You may experience a salty or metallic taste when the port is flushed.
  • When the medication is ready, the nurse will connect the chemotherapy tubing to the port tubing. Most chemotherapies are infused by a pump programmed to give the correct amount of medication over the correct amount of time.
  • Once the chemotherapy has been infused, the nurse will flush the port tubing with more normal saline. Some ports require a solution called heparin lock as well. This helps prevent blood clots from forming in the port device.
  • The nurse will then remove the Huber needle and place a bandage or small dressing over the puncture site. You may shower and bathe anytime after the port needle is removed.

Why Doesn't My Clinic Do My Blood Draw Through a Port?

Although it's convenient to use the port for labs, there are times you may need a venipuncture (blood drawn from the arm) instead. Here are some reasons your bloodwork may not be done through your port:

  • There isn't qualified staff to access the port.
  • Certain labs require a venipuncture.
  • It's more expensive to use a port.
  • There is suspected damage to the port.
  • The port does not have blood return due to a blood clot or abnormal position.

A nurse or phlebotomist (healthcare professional who draws blood) must be trained in the correct method of cleaning or flushing a port before it can be used to obtain a blood sample.

Summary

A port is a device implanted under the skin to give access to a large vein. They are used when a person needs frequent blood draws or IV medications. They are also used to administer chemotherapy drugs that are too dangerous to give through small veins. Their main benefit is safety, and they can be left in place long-term.

A Word From Verywell

Being diagnosed with cancer and needing chemotherapy can be scary and stressful. Although the thought of getting a port may also be unnerving, it is essential for your safety and well-being during cancer treatment. Once the port site heals, you can resume normal daily activities and may not even know it's there. In addition, having a port can alleviate the worry of being poked numerous times. Once your treatment is over, you and your oncologist can discuss the best time for the port to be removed.

Frequently Asked Questions

  • How long can you leave a port in?

    Depending on the type of cancer, you may need to keep your port in for up to a year after treatment. Many people, however, enjoy the ease of having a port and keep them in for years. As long as the port is properly functioning, there are no signs of infection, and it is flushed every 12 weeks, your port can stay in for the long term.

  • Who can draw blood from a port?

    All registered nurses, nurse practitioners, and doctors can draw blood from ports. Other clinical staff, like phlebotomists, may need a special certification to draw blood from a port. Each state and organization has its own rules about who can access ports.

  • Why can’t they get blood from my port?

    Sometimes a small blood clot called a “fibrin sheath” forms at the tip of the port's catheter. This clot prevents blood from being withdrawn from the port. The port device catheter can also become twisted or improperly positioned, preventing a blood return.

  • Does it hurt to draw blood from a port?

    Drawing blood from your port hurts about the same as having blood drawn from your arm. Placing ice over your port site 10 minutes before the puncture can alleviate some of the discomfort. Numbing cream is available by prescription if you find your port puncture too painful.

  • Does a port need to be cleaned?

    Before your port is accessed (punctured) with a Huber needle, the nurse will clean your skin with an alcohol solution to prevent infection. Once the port is accessed, it is flushed with normal saline to clean or rinse the inside of the device.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Li G, Zhang Y, Ma H, Zheng J. Arm port vs chest port: a systematic review and meta-analysisCMAR. 2019;11:6099-6112.

  2. Nurse.org. What is a port-a-cath?.

  3. American Cancer Society. Tubes, lines, ports, and catheters used in cancer treatment.

  4. American Society of Anesthesiologists. Practice guidelines for central venous access 2020: An updated report by the American Society of Anesthesiologists Task Force on Central Venous Access. Anesthesiology. 2020;132(1):8-43. doi:10.1097/ALN.0000000000002864

  5. Centers for Disease Control and Prevention. Guidelines for the prevention of intravascular catheter-related infections.

By Serenity Mirabito RN, OCN
Serenity Mirabito, MSN, RN, OCN, advocates for well-being, even in the midst of illness. She believes in arming her readers with the most current and trustworthy information leading to fully informed decision making.

Originally written by
Pam Stephan
Pam Stephan is a breast cancer survivor.
Learn about our editorial process