LPN IV Series: Venipuncture and Maintenance

Often, a patient will need venipuncture for some reason. They may need routine labs drawn, they may be suffering from a chronic illness, or they may be acutely ill. Regardless of the reason behind venipuncture, specific content must be reviewed.

First off, the anatomy of the skin and veins must be discussed. Understanding veins, how they work, and where they lead is essential.

It is also essential to understand the types of blood tests that can be commonly performed and what each test will tell us, such as how organs are functioning.

The steps of inserting a needle and IV catheter are outlined, including the necessary equipment and techniques to ensure venipuncture and IV success. The course will also outline the assessment, maintenance, and documentation of the venipuncture and IV procedure.

Steps for adults versus pediatric IV and venipuncture are discussed as the process can differ depending on the patient's age.

First, let's discuss the skin and veins to gain a foundational understanding to increase the chances of venipuncture success.

IV therapy is an invasive procedure. Only veins are used for venipuncture. If blood pulses out of the catheter, you have hit an artery. Discontinue the catheter and hold pressure for 10 minutes.

Alert: Aseptic technique should be used on all venipunctures, tubing, and dressing changes.

Before you begin the venipuncture, consider the following:

• The purpose
• Duration of use
• Condition of veins
• Type of infusion
• Patients medical condition

When selecting a vein to perform venipuncture, consider the following factors:

• Catheter size - Select a catheter with the shortest length and diameter that accommodates the provided therapy. A 20-gauge (20G) catheter can be used for blood transfusions if the patient cannot tolerate an 18G. Smaller catheters lyse the red blood cells during infusion, defeating the purpose.
• Type of solution - Hypertonic solutions and various medications can irritate the vein. Consult with the pharmacy regarding the properties of the medications or solutions being delivered.
  • Alert: Do not administer continuous vesicant chemotherapy and parenteral nutrition exceeding 10% dextrose or 5% albumin in a peripheral line. A 20G or larger catheter is needed in the forearm or above for IV contrast.
• The vein condition - If the vein has recently been used or is bruised/red/swollen, do not use it.
• Duration of therapy - Long-term therapy will require frequent venipunctures. When possible, alternate arms and always start distally.
• Patient's age:
  • Infants have fewer accessible sites than older children and adults.
  • In toddlers, the feet and hands are the most accessible sites.
  • The hands and the antecubital region offer the best sites for children, adolescents, teens, and adults.
  • The elderly may have very fragile veins, fragile valves, and a lack of connective tissue to stabilize the veins (rolling veins).
• Patient preference - Use the non-dominant side whenever possible. Ask the patient if they have ever had an IV before and which site they prefer.
• Patient activity – Consider other placement beside the hand if the patient uses a walker, crutches, or wheelchair (Nettina, 2019).

Veins for Venipuncture

Central lines should be used (Nettina, 2019):

• When infusions are:
  • Hypertonic
  • Highly irritating (chemotherapy, parenteral nutrition)
  • Required rapid or high-volume
• When peripheral blood flow is diminished (shock, dehydration)
• When peripheral veins are not accessible (obese, frequent venipuncture)
• When hemodynamic monitoring is desired
• When long term IV therapy is expected

Central lines will be discussed in another course in this series.

Butterfly (winged) metal needles are for short-term drug administration and should not be left in place. The needles easily cut the vein and lead to infiltration with the slightest movement.

Use only catheters with a safety protection feature to guard against needlesticks (Nettina, 2019).

Use an aseptic technique when changing tubing and bags or bottles. The system can be set up in the medication room or at the patient's bedside. Most medication rooms have enough room to lay out the equipment and control the sterile ends of the bags, bottles, and tubes.

Use only bags or bottles that are sealed and within the expiration date. If the contents of the bag or bottle of IV fluid are cloudy or not the color it is supposed to be, do not use it. The addition of medication or parenteral nutrition may change the color. These additions should be noted on the bag by the pharmacy or by the nurse who added the substance.

Microdrip systems deliver 60 drops/mL. It is used when infusing small volumes. It is commonly used with infants and pediatrics. Microdrips reduce the risk of clotting in the line because of the slow infusion rate. It also provides fluid overload safety by restricting the maximum amount infused. Microdrip systems may have a drip chamber that contains up to 100 mL and is clamped off from the liter bag of fluids. The restriction is an additional safety measure to prevent fluid overload in at-risk patients (Nettina, 2019).

Macrodrip systems deliver 10, 15, or 20 drops/mL. 20 drops/mL is the most common type. Most facilities use a standard macrodrop size to prevent potential errors. Macrodrips are used in most adults for large quantities and rapid infusions. Most IV bags and glass bottles have a built-in air vent to prevent a vacuum. If a glass bottle has no vent built-in, vented tubing can be used. Most facilities standardize their bags or bottles to avoid problems, but most facilities use bags.

Filters are usually built-in lines used for blood or parenteral nutrition. Some filters can be added between the tubing and the IV bag. Most facilities standardize to avoid problems. If you need a special filter for blood infusion, the blood bank will provide that add-in filter or special tubing with a built-in filter.

Most infusion pumps require special tubing. The facility will standardize this tubing as well. Secondary administration tubing is used to piggyback IV medication bags to infusion tubing. The medication bag should always be hung higher than the IV-liter bag (Nettina, 2019).

There is specially coated tubing that prevents the leaching of polyvinyl chlorine from the tubing. The coated tubing should infuse nitroglycerin, paclitaxel, and cyclosporine.

Tubing add-in devices are available. They include:

• Single and multi-lumen extension sets
• Extension loops
• Needleless connectors
• Inline filters
• Manual flow-control devices
• Stopcocks

Minimize tubing manipulation and multiple components in the tubing to reduce the chances of contamination.

The frequency of changing the IV administration sets is specific to facilities. The following are evidence-based recommendations for changing schedules. Primary and secondary continuous tubing should be changed no more frequently than every 96 hours and at least every seven days. Tubing used for parenteral nutrition should be changed every 24 hours. The tubing used for blood must be changed every 4 hours. Tubing for fat emulsion infusion must be changed every 12 hours.

The tubing system must be labeled when it is hung with the date, the time it was opened, and the person's initials applying the tubing. The labeling allows everyone to identify when the tubing needs to be changed (Nettina, 2019).

The provider (doctor, physician assistant, or nurse practitioner) orders the flow rate. The nurse and the pharmacist's role is to evaluate the order's appropriateness based on the patient's condition. The nurse's role is also to regulate and maintain the flow rate and monitor the total input.

The nurse should notify the provider if the patient's rate does not seem correct. Considerations include age, patient condition, patient tolerance of the infusion, and the prescribed infusions.

The very young and elderly can easily experience fluid overload. The flow rate should be slower, or the patient must be carefully monitored.

The patient's condition will often determine the flow rate. Someone in hypovolemic shock requires a large amount of fluid. Someone with heart or renal failure requires restricted fluids.

Some medications cause vascular irritation (potassium chloride, Phenergan) or have the potential for an allergic response (antibiotics). These medications should be more diluted or infused slowly.

Some medications' efficacy is based on the administration time and infusion speed (antibiotics). Some medications must be titrated based on the patient's response (dopamine, nitroprusside, heparin).

An infusion pump controls the flow rate more efficiently and accurately; therefore, using a pump is considered the best practice. However, pumps are expensive; therefore, they may be a limited resource. Infusions not on a pump require more frequent monitoring of the flow rate. Flow control dials or clamps and occlusive clamps can slip or be dislodged. Another potential flow problem is the stretching and distorting of the tubing due to patient movement. Cold or viscous solutions can also cause flow fluctuations (Nettina, 2019).

Both short-term and long-term IVs require maintenance.

• Flush the catheter with NS and aspirate blood before each infusion to assess catheter patency.
• Flush the catheter with NS to clear the catheter lumen and prevent mixing with incompatible medications.
• Flushing with NS is as effective as flushing with heparin to maintain catheter patency.
• Flush 10 mL NS to remove fibrin deposits, drug precipitate, or other debris to ensure patency.
• Locked catheters must be flushed before and after medication or solution administration.
• Prefilled syringes are preferred for flushing rather than a nurse-filled syringe.
• Use a push-pause method to inject the medication. Check the catheter for patency if resistance is met. Do not force.

Heparin is no longer routinely used to flush and maintain catheters. However, you may still hear the term heparin lock or hep-lock. Hep-lock refers to a catheter with a short tube that is connected to the IV but not to a fluid bag or bottle. The hep-lock allows the patient freedom when the IV infusions are intermittent (Nettina, 2019).

An aseptic technique is used to access a hep-lock or IV tubing. Clean the hub of the hep-lock or tubing with alcohol. Do not contaminate the cleaned hub. Remove the protective cover from the injection device or tubing and connect it to the hub. Most systems have needless connecting injection devices and tubing. If not, tubing connected by a metal needle should be taped to the tubing to prevent accidental removal.

The infusion pump has pressure limit defaults to prevent adverse effects. However, the upper limits may be manually increased based on the following:

• The patient's activity level
• The viscosity of the fluid/medication
• The diameter and length of the catheter
• The rate of fluid/medication being administered

Medications and solutions administered may be diluted, added to a burette, administered with an infusion pump, used in a syringe, or administered directly as a push or a bolus. The proper method of administration depends on the patient's circumstances and the type of catheter used.

The medication must be diluted into a smaller volume when using a burette. The fluid/medication should be hung, and the roller clamp should be slowly opened to allow some of the contents into the burette. An additive port can be used to inject the drug.

If a secondary infusion is necessary, it can occur through a bag or syringe, depending on the medication.

A syringe driver is often recommended for pediatric patients that weigh less than 10kg. The required volume of diluent should be drawn in a syringe. Pull back on the syringe to inject the medication into the syringe. Before accessing the additive port, it should be scrubbed and cleaned. A label with the drug, dose, volume, diluent, date, and time should be on the bag, as well as the nurse's signature.

For patients receiving intermittent transfusions, the disconnected IV lines should be discarded.

Before administration of fluids and medications, the cannula should be flushed. For patients who are not actively receiving fluid or medications through their IV line, it should be flushed at least once per shift. Sterile 0.9% sodium chloride should be used for flushing. A 10 mL syringe should be used for flushing as it prevents excess pressure and potential catheter rupture. If any resistance is felt when flushing, the patency should be reassessed.

Catheters should be flushed:

• Directly after the catheter is placed.
• Before and after the infusion of fluid or medications.
• Before and after blood is drawn for the lab.
• When the catheter dressing needs to be changed.

As dressings are pertinent for protecting against complications such as infection and dislodgement, they must be kept clean, dry, and secure. Any excess fluid or blood leakage indicates the need for a dressing change. If possible, a transparent film should be used unless the patient is allergic.

The old one should be removed carefully when changing the dressing, ensuring the cannula stays in place. The edges of the tape should be loosened slowly, staying close to the skin's surface. While changing the dressing, assess the insertion site. A 2% chlorhexidine and 70% alcohol swab should be used for cleansing the area as needed. The skin should completely air dry before applying the dressing.

A cotton ball or small piece of gauze can be placed under the catheter's hub to reduce pressure. An IV board or splint can help stabilize the extremity when activity and movement are expected. Ensure that the extremity is positioned and strapped in a neutral position to reduce the chance of injury. The splint should be assessed daily and if soaked with blood or drainage. Overall, everything should be secure, the site visible if possible, the tape should not be too restrictive, and the patient should be free from harm.

Document all care provided, especially when performing venipuncture and IV maintenance. Documentation should include information on the needle, the site, and each time it is assessed or care is provided, such as a dressing change.

As a note, extension sets should be changed when the insertion site is changed or if contamination and/or injury has occurred (Nettina, 2019).

Assess the IV catheter at least daily for signs of infiltration, infection, phlebitis, or other complications. Also, remove if there are any signs of complications.

The insertion site should be assessed for signs of infection, including pain, swelling, and redness. The position of the catheter and the patency of the catheter should be assessed. The site should also be checked for any signs of extravasation, which can cause tissue damage and necrosis. Because pediatric patients are vulnerable, their sites should be checked hourly.

When assessing the dressing, ensure it is secure, intact, dry, and free of soaking blood. The bandages or dressings should not be so tight that it cuts off circulation, but also should not be too loose that it falls off, increasing the chances of catheter damage. The insertion site should always remain visible for assessment; transparent dressings can increase visibility.

If the patient has fluids or medications running through an IV, the fluid or medication, the infusion rate, and the equipment to infuse it should be assessed.

The catheter should be removed as soon as the patient no longer requires it; this prevents any further or unnecessary consequences (Nettina, 2019).

The peripheral IV catheter is removed when treatment is complete or a complication requires removal. To remove a catheter:

• Stop all fluids or medications that are infusing.
• While stabilizing the access device, lift the tape and secure the device.
• Place a folded gauze over the insertion site.
• Apply pressure to the insertion site as you pull out the catheter.
• Hold pressure until the site stops bleeding.
• Apply a dressing per the facility policy.
• Educate the patient to watch for bleeding and refrain from using that arm to lift heavy items for 30 minutes.
• Dispose of tubing and catheter per facility policy (Nettina, 2019).

There are complications following venipuncture and IV insertion that should be discussed (Nettina, 2019).

Infiltration is caused by the dislodgement of the catheter from the vein with an unintentional infusion into the surrounding tissue.

Extravasation is the infiltration of vesicant solutions into the surrounding tissue. Vesicants include chemotherapy, hyperosmolar solutions, parenteral nutrition, and potassium chloride.

Phlebitis is caused by the following:

• Injury to the vein during venipuncture or prolonged catheter use
• Catheter too large for the vein
• Poor aseptic technique
• Irritation to the vein because of rapid infusion or irritating solutions (smaller veins are more susceptible)
• Clot formation at the end of the catheter due to slow infusion rates or inadequate hemodilution of infused medication or solutions
• Phlebitis is more commonly seen with synthetic polyurethane catheters than with silicone catheters

Catheter-associated bloodstream infection is caused by:

• Underlying thrombophlebitis
• Contaminated equipment or solutions
• Prolonged placement of the IV catheter, tubing, or solution container
• Lack of aseptic technique with insertion or dressing changes
• Cross-contamination from other infected areas of the body
• Critically ill or immunosuppressed patients

Fluid overload is caused by the following:

• The infusion of excessive IV fluids. The elderly, infants, and patients with cardiac or renal failure are at greater risk.

Air emboli are caused by:

• When air enters the catheter during tubing change or catheter removal of a central venous line (negative intrathoracic pressure sucks in the air during inspiration)
• Air in tubing delivered by IV push or infusion

Occlusion or slow flow is caused by:

• Malposition of the catheter against the side of a vein or valve
• Clot at the end of the catheter
• External mechanical causes (kinking of tubing, clogged filter, needless connector)

Hemorrhage is caused by:

• Loose connections of tubing or injection port
• Inadvertent removal of the catheter
• Anticoagulation therapy

Venous thrombosis is caused by:

• Infusion of irritating solutions
• Infection along the catheter
• Fibrin sheath formation around the catheter with eventual clot formation
• Patient factors such as:
  • Hypercoagulable state (cancer, diabetes, end-stage renal failure)
  • History of deep vein thrombosis
  • Surgical or trauma patients
  • Critical care patients
  • Extreme age

Venipuncture is a scary and stressful experience for a child. Even though it is a routine procedure, needles can be scary. Ensuring the approach is calm may help to ease the stress and anxiety of routine venipuncture.

There are ways to ease the stress for children. First off is a distraction; this may be a good method that can be performed by the nurse or by the parents/caregivers. Positioning may decrease anxiety. However, if a child cannot see what is happening, it may increase anxiety. The use of music has been researched and shows it helps to ease stress. Family involvement in the process is crucial as they provide great comfort. If the child is fearful of pain, topical analgesics can be used.

Research has also shown that oral sucrose can be used in patients younger than six months old.

Education is just as important for children as it is for adults. Assure the child that the blood loss will not be harmful to them. In fact, a Band-Aid with cool designs may reassure the child that they will not bleed too much. However, bandages must be used cautiously in children who may remove them and try to swallow them.

Skin preparation is often performed in different ways. Chlorhexidine, isopropyl alcohol, and povidone-iodine have all been used. Though they each have benefits, disadvantages do exist. Follow policy protocol for skin preparation (Elsevier, 2022).

There are some general tips to follow if venipuncture or blood samples are unsuccessful.

The patient or the needle may need to be repositioned.

The collection tube may not be up against the back of the needle/the hub.

The vacuum seal in the tube could be defective, and another tube should be tried.

The tourniquet may be too tight.

Probing can be damaging to the vein and harmful or painful to the patient. Depending on the patient and the circumstance, they should not be stuck more than twice by the same person (Nettina, 2019).

General documentation of IV therapy should include the following:

• Date and time of insertion
• Site and preparation of insertion
• Number of attempts to start IV
• Size and type of catheter inserted
• Medications and solutions hung
• Total intake of IV fluids
• Date and time of removal
• Management of complications

Patient education should include the following: 

• Plan of care and goal of treatment
• Purpose of IV
• Care of the IV devices and insertion site
• Potential complications (Nettina, 2019)

Jessie is a phlebotomist who works in the laboratory department, often assisting with blood draws for patients in the emergency department.

Jessie has received a call about Ethel, a 72-year-old female in the emergency department with complaints of nausea, vomiting, diarrhea, and intermittent stomach pain for three days.

The emergency department sees Ethel within thirty minutes of her arrival. A nurse examines the patient and decides that the patient will need blood work and scans. Because the patient's hydration has been affected by nausea and vomiting, she will likely need fluids replaced. Instead of sticking her twice, once for blood and once for an IV, the plan is to place an IV and draw labs simultaneously.

The nurse is having difficulty finding veins. She has tried a tourniquet, fist-pumping, and the use of gravity. The lack of hydration probably contributes to the difficulty in finding veins. The nurse tries to stick a 20G into the left antecubital area, but there is no flashback. The nurse tried a different syringe and also tried repositioning the arm. Still, there was no blood return. She tried to flush the catheter but was met with resistance.

The nurse decides to withdraw the needle and try again elsewhere. She spots a vein in the left hand that she thinks may work. She starts at a 40-45° angle with a 20G needle and pushes when she feels she is in the vein; she receives a small drop of blood return, but no more. The patient begins complaining of pain and burning, and the skin is visibly bruising. It is likely that she has gone through the vein wall on both sides, blowing the vein. The nurse withdraws the needle and decides to call Jesse.

Jesse makes his way to the emergency department and examines the veins on Ethel's arms. He has Ethel lay in bed and dangle her right arm off of the bed. While doing so, he also has her slowly pump her fist. He can palpate a vein in the right antecubital area. Jesse starts at a 20° angle as it is a deeper vein. He gets flashback and can withdraw blood and finish starting the IV, easily flushing NS through the vein.

What could the nurse have done differently? Was it just the luck of the draw? It is very possible that if the nurse's angles were changed, she would have gotten blood return and not blown the vein.

Venipuncture is a procedure that is commonly performed in many different settings. Because venipuncture can be complex, certain information must be reviewed. First, background information must be given about the skin and veins. Because our skin is the barrier against protection, any time it is broken, the risk of infection increases, including with venipuncture- this is why it is essential to try and obtain successful venipuncture in one attempt. Because the arterial system is also very complex, nurses should ensure adequate knowledge of arteries, veins, and capillaries.

It is also important to understand the types of tests that can be performed with blood. For example, blood chemistry panels can be run to determine electrolyte levels and minerals. Blood lipid profiles can be performed to monitor good and bad cholesterol. Liver function tests can be performed to determine the level of functioning of the kidney. These are just a few examples of the information that our blood can tell us.

How blood tests are taken and how the results are configured are also important. There are many different tubes with various colored tops. Each top represents additives and the types of tests that can be run. Blue top tubes are for hematology tests, yellow tops look at hormones, tumor markers, and blood toxicology levels, and tubes with dark green tops look at insulin and renin. These are just a few examples of color indicators with blood tubes.

Another important aspect of venipuncture is the collection of blood cultures, which are essential in identifying bacteria in the blood. The collection of blood cultures must be performed in an aseptic and proper manner. Collecting the right amount of blood is necessary to determine the type and growth of bacteria.

The insertion of an IV needle and catheter must require a proper technique to reduce the risk of complications. Several factors should be reviewed before insertion. The catheter size, the type of solution, the vein and its condition, the duration of therapy, the age and status of the patient, and the patient's preference and activity should all be considered before the insertion procedure. There are advantages and disadvantages to each insertion site. For example, the inner wrist is excellent for butterfly needles. However, it usually results in a painful insertion for the patient. The antecubital veins allow for rapid infusions because of the size of the vein. However, they restrict the patient's motion. The advantages and disadvantages and risks and benefits must be reviewed with the patient.

After an insertion site has been decided, it is time to prepare the equipment. Depending on the site and circumstances, additional equipment may be needed. However, basic equipment includes safety needles, syringes, tape, bandages, a tourniquet, and gauze. The site should also be prepped, thoroughly cleaned, and allowed to air dry.

Depending on the location of the site, different angles of insertion should be used. For example, the deeper the vein, the steeper the approach could be. A deep vein should be done with at least a 20-30° angle.

It is possible that vein finding can be tricky, but there are methods to find or distend a vein, such as ultrasound, gravity, or hydration.

If no flashback is received, tips and tricks, such as positioning, may allow a flashback. However, if the tips do not work and continual resistance is met, the needle is not in the right place, and the catheter is not patent.

After placing a catheter, the site can be used for venipuncture, infusion, or as needed. When infusions are ordered, the tubing should be correctly used. Tubing should be primed, and bags may need to be spiked. Follow facility protocol with these procedures.

Flow rates and infusion rates must be calculated correctly to prevent patient harm. Infusion rates are usually ordered as volume (mL) per hour. An infusion pump measures the flow rate in mL/hours. To find the rate in mL/hour for an infusion pump, divide the total number of mL by the total number of hours. If the rate seems incorrect, have someone else double-check and confer with the provider.

For patients who will have insertions long-term, regular maintenance should occur. Maintenance includes ensuring the catheter stays patent with flushing. Assessment of the catheter includes looking for infection and infiltration. Complications include infiltration and extravasation, phlebitis, circulatory overload, and air embolism.

Venipuncture in children requires a different approach. Steps should be taken to ensure that the pediatric patient is educated about the procedure and that their anxiety/stress is calmed. The family should be involved in the procedure as much as possible; this can decrease anxiety for the child. Precautions should be taken when performing venipuncture or an insertion in infants, as they can easily and accidentally pull out the catheter.

A lot of information on venipuncture and maintenance has been provided. It is important to review facility protocols and policies to follow their guidelines and regulations. Protocols should outline hand hygiene and an aseptic technique for certain procedures, which is always a critical component of care. No matter the procedure, ensure patient understanding and patient comfort. Always explain the steps of any procedure to maximize the patient's understanding while minimizing their anxiety.

• Beecham, G.B., & Tackling, G. (2022). Peripheral Line Placement. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. Visit Source.
• Bond, M., Crathorne, L., Peters, J., Coelho, H., Haasova, M., Cooper, C., Milner, Q., Shawyer, V., Hyde, C., & Powell, R. (2016). First do no harm: pain relief for the peripheral venous cannulation of adults, a systematic review and network meta-analysis. BMC anesthesiology, 16(1), 81. Visit Source.
• Doyle, G. R., & McCutcheon, J. A. (2015). 8.4 priming IV tubing and changing IV fluids and tubing. Clinical Procedures for Safer Patient Care. Visit Source.
• Elsevier. (2022). Clinical skills │ blood specimen collection: Venipuncture (pediatric). Elsevier. Visit Source.
• Lamy, B., Dargère, S., Arendrup, M. C., Parienti, J. J., & Tattevin, P. (2016). How to Optimize the Use of Blood Cultures for the Diagnosis of Bloodstream Infections? A State-of-the Art. Frontiers in microbiology, 7, 697. Visit Source.
• Lee, S. M. C., Martin, D. S., Miller, C. A., Scott, J. M., Laurie, S. S., Macias, B. R., Mercaldo, N. D., Ploutz-Snyder, L., & Stenger, M. B. (2020). Venous and Arterial Responses to Partial Gravity. Frontiers in physiology, 11, 863. Visit Source.
• Nettina, S. M. (2019). Lippincott manual of nursing practice (11th ed.). Wolters Kluwer.
• National Heart, Lung, and Blood Institute. (2022). Blood Tests. National Heart, Lung, and Blood Institute. Visit Source.
• Ombelet, S., Barbé, B., Affolabi, D., Ronat, J. B., Lompo, P., Lunguya, O., Jacobs, J., & Hardy, L. (2019). Best Practices of Blood Cultures in Low- and Middle-Income Countries. Frontiers in medicine, 6, 131. Visit Source.
• Rosso, J. D., Zeichner, J., Alexis, A., Cohen, D., & Berson, D. (2016). Understanding the Epidermal Barrier in Healthy and Compromised Skin: Clinically Relevant Information for the Dermatology Practitioner: Proceedings of an Expert Panel Roundtable Meeting. The Journal of clinical and aesthetic dermatology, 9(4 Suppl 1), S2–S8.
• Tucker, W.D., Arora, Y., & Mahajan, K. (2022) Anatomy, Blood Vessels. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. Visit Source.
• University of North Carolina (UNC) Medical Center. (2021). EVACUATED BLOOD COLLECTION TUBE GUIDE. UNC Medical Center. Visit Source.