If you’re a nursing student or are studying to be a phlebotomist, you’ll need to be prepared to perform vital tasks, one of which is drawing blood. Phlebotomists are responsible for taking blood samples. But what if you’re a nurse and a sample needs to be taken right away, but the phlebotomist isn’t available? You need to know how to draw blood.
You may be surprised to learn that drawing blood, also called venipuncture, is not a standard procedure taught to nursing students. Why? Some hospitals deem it too risky to have nurses practice drawing blood. Because of this, they suggest that they go elsewhere to learn how to draw blood.
While it may not be part of your regular training, knowing how to safely draw blood can be crucial if a blood sample needs to be obtained quickly. A blood sample is required for most tests, which means it can be difficult to arrive at an accurate diagnosis without first drawing blood and testing it in the lab.
If you want to know how to draw blood, you can’t learn just by reading about it or watching demonstrations. It requires practical experience and training. Before you can practice drawing blood, it’s important to get a baseline understanding so that you’ll know what to expect. Follow safety procedures carefully, and you should have no trouble with this routine process.
Finding The Vein
Before you can learn how to draw blood, you’ll need to learn how to find the vein. When drawing blood from an adult, try to identify the median cubital vein. This is a large vein that should be easy to draw from. It’s located between the bicep and forearm, also known as the cubital fossa. The median cubital vein is usually chosen because it poses little risk of damage to nerves or arteries.
In some patients, the median cubital vein may be visible just under the skin. However, each individual is different, and sometimes locating a vein can be more difficult. Nicotine can constrict veins, so if your patient is a smoker or any type of nicotine user, this might make the task more difficult.
Caffeine can also constrict veins, which is a common challenge when drawing blood early in the morning. Intravenous drug use causes veins to collapse, making many veins like the median cubital nonviable for drawing blood. In addition, some people have naturally smaller veins or mobile veins which roll instead of remaining stationary.
How To Draw Blood Safely
If you want to know how to draw blood, you need to be prepared for everything which might present a challenge. Consult a map of the circulatory system if you need help. You might feel out of your depth if you’re inexperienced with drawing blood. If you don’t feel you can go on, then you should ask for a more experienced phlebotomist to step in.
Before you begin, check for any signs of scarring from previous needle punctures, hematomas, or blood clots. If for some reason you can’t draw a sample from the median cubital vein, you can opt instead for the basilic vein, but know that this means a higher risk of accidental injury to a nerve or artery. If you patient has just undergone a blood transfusion, a surgical procedure, or has an infected wound on one arm, draw blood from the opposite arm instead.
Gathering The Supplies
You might already have the supplies you need if you’ve got a medical kit handy. If not, you’ll gather the supplies you’ll need. This should be a simple matter if you have access to the medical supplies available in any hospital storeroom.
You’ll need disposable rubber gloves for your protection, biohazard bags which won’t leak, and a bag which won't puncture for you to dispose of sharp needles. These items are for your protection and safety. If, for any reason, you experience a leak or tear with any of the above items, stop the procedure immediately. Do not touch blood with your bare hands for any reason.
You’ll need blood collection tubes, specimen labels, and the proper laboratory forms. The labels ensure that once the samples are drawn, they can be processed correctly by the lab tech staff. Without properly labeling your specimens they are likely to get lost among the hundreds of other samples, and a mislabeled specimen will cause confusion and might result in a misdiagnosis.
A tourniquet, gauze, and alcohol swabs will all be needed, as will adhesive bandages. It’s a good idea to have enough of these supplies to exceed the need, just in case you need more than you expected. Just be sure to return any clean, unused materials to the storeroom when you’re finished.
Finally, you’ll need needles and a device to transfer the blood into your collection tubes. Handle your needles carefully.
Drawing The Blood
If you haven’t sterilized them already before you start it’s a good time to wash your hands to ensure that you don’t accidentally facilitate the spread of infection. This crucial step can save lives and prevent undue suffering to patients who might otherwise be exposed to bacteria present in hospitals and other medical facilities. When you’re done, apply your latex gloves.
With your materials collected and your patient ready, consult your forms to confirm that the test has been ordered by a doctor. When you’re ready to begin, speak with the patient you’ll be drawing blood from. Remember that this procedure might be frightening for them even if it’s routine for you.
Ask questions about the patient’s medical history. Are they aware of any allergies they might have to latex? Are they currently taking blood-thinning medications? Do they have a family history of hemophilia that they know about? Get as much information as possible to avoid a complication or issue arising from drawing blood.
Once you’ve asked questions to reduce risk factors, tell the patient what you’ll be doing step by step as you go along. Make sure they’re informed of what you’re doing. This will help put them at ease and move the process along.
Instruct the patient to hyperextend their arm, then take the tourniquet and wrap it 3-4 inches above the cubital fossa if you plan to draw from the median cubital vein. You should wait no more than two minutes before beginning the blood draw. Ask the patient if they’re experiencing pain, numbness or tingling. Watch to make sure that the vein doesn’t change color.
So long as everything appears normal, and the patient isn’t feeling any unusual discomfort, you can proceed. The patient should make and hold a fist. It isn’t necessary to do this repeatedly. Holding a fist is sufficient. Tap the vein with your finger to dilate it, then take your alcohol swab and sterilize the area around the planned injection site.
Starting The Blood Draw
With one hand, take your needle. Hold the patient’s arm below the injection site with your other hand. Hold the skin firmly to make sure that vein doesn’t move as you insert the needle through the skin and into the vein. This should be done at a 15- to a 30-degree angle.
If you’ve successfully punctured the vein, you’ll see blood appear in the catheter. Attach the collection tube and watch to make sure that blood begins flowing at a slow, even pace. When the collection tube has been filled, you can remove the tourniquet and withdraw the needle.
Quickly take your gauze and press down on the injection site. Wrap a bandage around the gauze to hold it in place. Take the used needle and place it carefully into your biohazard disposal receptacle. Remove your gloves and dispose of these as well. Be sure to label all your specimens carefully before depositing them in the lab.
Best Practices in Phlebotomy
This section of our article will cover all of the steps that are recommended for safe phlebotomy and it will go over the accepted principles for drawing blood and for blood collection. We will include some background information, practical guidance, and the relevant best practices in phlebotomy.
Background information on the Best Practices in Phlebotomy
Best practices for phlebotomy include the following factors:
- Planning ahead
- Quality control
- Using an appropriate location
- Standards for quality care for patients
- Standards for quality care for health workers
- Quality of laboratory sampling
- Availability of appropriate supplies
- Availability of post-exposure prophylaxis (PEP)
- Availability of protective equipment
- Appropriate training in phlebotomy
- Avoidance of contaminated phlebotomy equipment
- Cooperation on the part of the patients
This is the most important part of carrying out and procedures and this is usually completed at the very start of the phlebotomy session.
Using an Appropriate Location
The phlebotomist should work in a clean, well-lit, and quiet area. This applies whether the work is being completed with outpatients or inpatients.
An essential part of the best practice in infection prevention and control is quality assurance. In phlebotomy, this helps to minimize the chances of any mishaps. Below are examples of the important aspects of quality control:
Education and Training
It is absolutely necessary for all of the staff carrying out phlebotomy to have the appropriate education and training. This should include an understanding of anatomy, an awareness of the risks of blood exposure, and a knowledge of the consequences of poor infection prevention and control.
Standard Operating Procedures (SOPs)
Standard operating procedures are required for every single step or procedure involved in phlebotomy. These should be written out and should be readily available to all health workers.
Correct Identification of the Patient
Patient identification should be done through matching with the laboratory request form. For blood donations, the identity of the donor should be accurately matched to the results of the screening tests. When doing blood sampling, a system of identification and tracking is essential after the samples have been taken from the patient. This allows you to ensure that the sample is correctly matched with the result and with the patient or donor.
The Condition of the Sample
The condition of the sample should be in such a way that the quality of the results is satisfactory.
Part of the best practices of phlebotomy includes making safe transportation of the blood or blood products. This will improve the quality of the results from laboratory testing.
Incident Reporting System
It is essential to have a system in place for reporting any adverse events that may occur. A register or log book of some kind should be established and this should include accurate details of the incident, possible causes of the incident, and management of adverse events.
Quality Care for Patients and Health Workers
There are several factors which can improve the safety standards and the quality of care for both health workers and patients, and laboratory tests. These factors include the following:
Availability of Appropriate Supplies and Protective Equipment
The procurement of the supplies needed is the direct responsibility of the administrative structures that are responsible for setting up phlebotomy services. The management should provide hand-hygiene materials including soap and water or alcohol rub, well-fitting non-sterile gloves, single-use disposable needles, and syringes or lancing devices in sufficient numbers. This will ensure that every patient has a sterile needle and syringe or equivalent for each of the blood sampling. The administration should also ensure that there is sufficient laboratory sample tubes to prevent any dangerous practices. An example could include decanting blood to recycle laboratory tubes.
There are many safety-engineered devices that are available on the market today. These devices effectively reduce exposure to blood and injuries. However, the use of these types of devices should be accompanied by some other infection prevention and control practices and should involve training in their use. Not all safety devices available are applicable to phlebotomy. It is important to investigate all potential devices to determine their appropriate use, efficiency in protecting staff and patients, and their compatibility with existing phlebotomy practices before selecting one.
Availability of Post-Exposure Prophylaxis
Any accidental exposures and specific information about incidents should always be recorded in a register. There should be support services available for those who undergo any accidental exposure. PEP can help to avert hepatitis B and HIV infections. Hepatitis B immunizations should be provided to all of the health workers. This includes waste handlers and cleaners either as part of the PEP or upon entry into health care services.
Avoidance of Contaminated Phlebotomy Equipment
Tourniquets are a potential source of methicillin-resistant staphylococcus aureus (MRSA). Up to 25% of tourniquets are contaminated through lack of hand hygiene on the part of the phlebotomists, or through reuse of contaminated tourniquets. Additionally, the reuse of finger-prick devices and any other related point of care testing devices that are contaminated with blood have been implicated in outbreaks of hepatitis B.
To avoid any contamination, all common-use items such as glucometers must be visibly clean before any use on a patient, and all single-use items should never be reused.
Training in Phlebotomy
All members of staff must be trained in phlebotomy as this prevents unnecessary risks of exposure to blood and can help to reduce any adverse events for patients. Any groups of health workers who are historically not formally trained phlebotomy should be encouraged to take up this necessary training. A lack of infection prevention and control practices will result in poor safety for staff and could pose a risk to patients. The depth and length of training needed will be dependant on local conditions. However, the training should cover at least the essentials. Supervision by experienced staff members and structured training is essential for all health workers. This includes physicians who undertake the blood sampling.
The involvement and the cooperation of the patient is one of the essential markers of quality care in phlebotomy. This is mutually beneficial to both the patient and the health care worker. There should be clear information available to each patient who undergoes any form of phlebotomy.
Quality of Laboratory Sampling
There are some factors which influence the outcome of laboratory results during the transportation and collection. These factors include:
- Use of the correct gauge or a hypodermic needle to prevent any abnormal results or hemolysis.
- The use of recommended laboratory collection tubes
- Knowledge of staff involved in blood collection
- The anatomical insertion site for venipuncture
- Patient sample matching (for example - labeling)
- The use of recommended laboratory collection tubes
- Transportation conditions
- Interpretation of results for clinical management
Practical Guidance on Best Practices in Phlebotomy
Provision of an Appropriate Location
In a clinic or outpatient department, there must be a dedicated phlebotomy cubicle which contains a clean surface with two chairs - one for the patient and one for the phlebotomist. It should also contain a hand wash basin with soap, paper towels, and running water. Plus it should also contain alcohol hand rub.
In the blood sampling room for an outpatient department or clinic, there should be a comfortable reclining couch with an arm rest.
In wards and inpatient areas the curtain should be closed by the patient's bedside for privacy. It should also be ensured that blood sampling is done in a clean and private manner.
Provision of Clear Instructions
Ensure that the indications for blood sampling are clearly defined, either in documented instructions or in a written protocol.
Do’s and Don’ts for Drawing Blood
At all times you should follow the strategies for infection prevention and control. Below are the do’s and don’ts of infection prevention and control practices.
- Carry out hand hygiene (using alcohol rub or soap and water), and wash carefully. The washing should include wrists and the spaces between the fingers for a minimum of thirty seconds
- Do use a single-use device for all blood sampling and drawing
- Do use one pair of non-sterile gloves per patient or procedure
- Do disinfect the skin at the venepuncture site
- Whenever recapping of the needle is unavoidable, do use a one-hand scoop technique
- Do discard the used device (a syringe or needle is a single unit) immediately into a robust sharps container
- Do seal the sharps container with a lid which is tamper-proof
- Do immediately report any incident or accident which is linked to a needle or sharp injury. Always seek assistance in these instances and start PEP as soon as possible, following all protocols
- Do place laboratory sampling tubes in a sturdy rack before injecting it into the rubber stopper
- Do not forget to clean your hands
- Do not use a syringe, needle, or a lancet for more than one patient
- Do not use the same pair of gloves for more than one patient
- Do not wash gloves for reuse
- Do not leave any unprotected needles lying outside the sharps container
- Do not touch the puncture site after disinfecting it
- Do not recap a needle using both hands
- Do not overfill or decant a sharps container
- Do not delay PEP after exposure to potentially contaminated materials. Beyond 72 hours, PEP is no longer effective
- Do not inject into a laboratory tube while holding it with the other hand
How to Draw Blood Following the WHO Guidelines
Assemble The Equipment
Collect all of the equipment which is needed for the procedure and then place it within easy and safe reach on a trolley or tray. It is important to ensure that all the items are clearly visible. The equipment that is required includes:
Ensure that the rack which contains the sample tubes is close to you, the health worker, but is far away from the patient, to avoid it being accidentally tipped over.
- A supply of laboratory sample tubes, which should be stored upright in a rack and should be dry. Blood can be collected in any of the following: vacuum-extraction blood tubes, glass tubes with screw caps, sterile glass or plastic tubes with rubber caps (the choice of tube will be dependant on what is agreed with the laboratory)
- A sterile glass or bleeding pack if large quantities of blood are being collected
- An assortment of blood-sampling devices (syringes, needles, or safety engineered devices) of different sizes
- Well-fitting non-sterile gloves
- Alcohol hand rub
- 70% alcohol swabs for disinfecting skin
- A tourniquet
- Gauze or cotton wool balls for applying to the puncture site
- Writing equipment
- Laboratory specimen labels
- Laboratory forms
- A puncture-resistant sharps container
- Leak-proof transportation containers and bags
Identify and Prepare the Patient
When the patient is a conscious adult, follow the steps outlined below.
- Introduce yourself to the patient and ask for them to state their full name
- Check that the laboratory form matches with the patient’s identity
- Ask whether or not the patient has any allergies, phobias, or if they have ever fainted during any previous blood draws or injections
- If the patient is afraid or anxious, reassure them and ask what would make them more comfortable
- Make the patient more comfortable in a supine position if this is possible
- Place a clean paper towel underneath the patient's arm
- Discuss the test that is going to be performed and obtain verbal consent from the patient. The patient does have the right to refuse the test at any time before the blood sampling, so therefore it is important to ensure that the patient has understood the procedure that is about to happen
Select The Site
In General Patients
- Extend the patient’s arm and inspect the forearm or the antecubital fossa
- Locate a vein that is a good size and that is visible, clear, and straight. The median cubital vein lies between the muscles and is usually one of the easiest to puncture. Under the basilic vein there is an artery and a nerve, so puncturing in this area runs the risk of damaging the artery or nerve, and this area is usually more painful. Don’t insert a needle where veins are diverting, as this increases the risk of a haematoma
- The vein should be visible to the naked eye without having to apply the tourniquet. Locating the vein will help to determine the correct size of needle needed
- Apply the tourniquet around 4-5 finger widths above the venepuncture site and then re-examine the vein
In Hospitalized Patients
For hospitalized patients, do not take blood from an existing peripheral venous access site as this can give false results. Haemolysis, contamination and presence of any intravenous fluids or medication can alter the results. Physicians and nursing staff may access the central venous lines for specimens following protocols. However, specimens from central lines can carry a risk of erroneous laboratory test results or contamination.
It is not ideal, but is acceptable, to draw blood specimens when first introducing an in-dwelling venous device, before connecting the cannula to the intravenous fluids.
Perform Hand Hygiene and Put on Gloves
Wash hands thoroughly with soap and water and dry with single-use towels. If the hands are not visibly contaminated, clean with some alcohol rub - Use 3ml of alcohol rub on the palm of the hand, rub it into the fingertips, back of the hands and all over the hands until it is dry.
After performing the hand hygiene, put on the well-fitting, non-sterile gloves.
Disinfect the Entry Site
Unless you are drawing blood cultures or preparing for a blood collection, clean the site with a 70% alcohol swab for thirty seconds and allow it to dry completely. Alcohol is preferable to povidone-iodine. This is because the blood that is contaminated with povidone-iodine may falsely increase the levels of uric acid, phosphorus, or potassium in the laboratory test results. Apply firm but gentle pressure. Begin at the center of the venepuncture site and work downwards and outwards to cover an area that is 2cm or more. Allow the area to then dry. Failure to allow enough of the contact time increases the risk of contamination. Do not touch the cleaned site and definitely don’t place a finger over the vein to guide the shaft of the exposed needle. If the site is touched, you will need to repeat the disinfection.
Take The Blood
Use the following method when performing venepuncture:
- Anchor the patient’s vein by holding their arm and then placing a thumb below the venepuncture site
- Ask the patient to put their hand in a fist so that the vein is more prominent
- Enter the vein quickly at a thirty degree angle or less. Continue to introduce the needle along the vein at the easiest angle for entry
- As soon as an efficient amount of blood has been collected, release the tourniquet before removing the needle. Some guidelines will suggest removing the tourniquet as soon as blood flow is established, but it should always be removed before it has been in place for two minutes or longer
- Remove the needle very gently and then apply gentle pressure to the site with a dry cotton wool bud or with a clean gauze. Ask the patient to hold the cotton wool bud or gauze in place with their arm extended and raised. Be sure to tell the patient not to bend their arm as this can cause a hematoma
Fill the Laboratory Sample Tubes
When you are obtaining multiple tubes of blood, be sure to use evacuated tubes with a needle and a holder for the tubes. This system will allow for the tubes to be filled directly. If you do not have this system available, use a winged needle set or a syringe instead.
If a winged needle set or syringe is used, the best practice for this is to place the tube into a rack before going ahead and filling the tube. To prevent the needle from sticking, use one hand to fill the tube or use a needle shield between the needle and the hand which is holding the tube.
Using slow and steady pressure, pierce the stopper on the tube using the needle. Be sure not to press the syringe into the plunger as this additional pressure can increase the risk of haemolysis.
Whenever possible, try to keep the tubes in a rack and move the rack towards you. Inject into the appropriate colored stopper in a downwards motion. Do not remove the stopper at any time as this will release the vacuum.
If the tubes you are using do not have a rubber stopper, inject extremely slowly into the tube. Minimizing the velocity and pressure used to transfer the blood reduces the risk of haemolysis. Do not recap and remove the needle.
Before they are dispatched, invert the tubes which contain additives for the required number of times. This will have been specified by the local laboratory.
Draw Samples in the Correct Order
To avoid any cross-contamination of additives between the tubes, draw blood collection tubes in the correct order. Verify the recommendations with the local laboratory as color coding and tube additives may vary from laboratory to laboratory.
Clean All Contaminated Surfaces and Complete Patient Procedure
Begin by discarding the used needle and syringe or blood sampling device into a puncture-resistant sharps container.
Check all of the forms and labels for accuracy. The label should be written out clearly with all of the information required by the laboratory. This typically includes the patient’s first and last names, their date of birth, their file number, and the date and time that the blood was taken.
Discard all used items into the appropriate category of waste. Items used for phlebotomy that would not release a drop of blood if squeezed (for example, gloves) may be discarded in the general waste, unless the local regulations state otherwise.
After these steps have been taken, perform the hand hygiene again as previously described.
Recheck all of the labels on the tubes and forms before the dispatch.
Once all of this is complete, inform the patient that the procedure is over. Ask them how they are feeling. Check the insertion site to ensure that it is not bleeding and then thank the patient and say something encouraging and reassuring before they leave.
Prepare the Samples for Transportation
Pack the laboratory samples safely in a leak-proof plastic bag that has an outside compartment for the laboratory request form. Placing this requisition on the outside helps to avoid any chances of contamination. If there are multiple tubes then you should place them in a rack or a padded holder to avoid any breakages during the transportation.
Clean Up Any Spills of Blood or Body Fluids
If any spilling of blood has occurred (for example, if a laboratory sample has broken within the phlebotomy area or during transportation, or if excessive bleeding occurs during the procedure), be sure to clean it up. An example of a safe cleaning up procedure can be found below:
If a person has been exposed to blood through non intact skin, a puncture wound, or mucous membranes, complete an incident report. For transportation of the blood samples outside of a hospital, be sure that the transportation vehicle is equipped with a blood spillage kit.
- Put gloves on and a gown or apron if bleaching or contamination of the uniform is likely in a larger spill
- Mop up the liquid from large spills with paper towels and then place them into the infectious waste
- Remove as much of the blood as possible with wet cloths before disinfecting
- Review the surface and see if it will be damaged by a water and bleach solution
- For metal, cement and other surfaces that can tolerate a stronger bleach solution, flood the area with around 5000 parts per million (ppm) solution of sodium hypochlorite (1:10 dilution of a 5.25% chlorine bleach to water). This is the preferred concentration for larger spillages. Leave this area wet for around ten minutes
- For any surfaces which may become corroded or discolored by a strong bleach, clean it carefully to remove any visible staining. Make a weaker solution and leave it in contact for a longer period of time. An example of this would be an approximately 525 ppm solution (1:100 dilution of a 5.25% bleach). This will be effective
- Prepare the bleach solution fresh on a daily basis and keep it in a closed container as it will degrade over time and when in contact with the sun
How to Draw Blood: Conclusion
Knowing how to draw blood is something that all sorts of medical professionals will be called upon to do at one point or another. If you’ve never done it before, the process can be intimidating. The important thing is to pay attention, follow all safety procedures to the letter, take it step by step and get as much practice as possible before attempting to draw blood from a patient on your own.
If possible, look for opportunities for hands-on training from in your area. Courses in venipuncture are available in nursing colleges and medical universities. Seek them out if venipuncture isn’t part of your regular coursework.
Prospective employers, especially those in intensive care wards, want to be assured that you know how to draw blood. So do your patients. The more practice you have, the better chance you’ll have of anticipating problems before they arise. Even if you’re diligently paying attention to every detail, the unexpected can still derail you.
Any phlebotomist will admit that drawing blood requires intuition as well as preparation. With experience, you’ll gain the confidence to proceed with a venipuncture procedure even if you have difficulty finding a vein in the patient’s arm. But until you’re prepared, it’s a good idea to practice with easier blood draws. Now you know how to draw blood practice, practice, practice.