The Phlebotomy Procedure
Blood banks and diagnostic centers are the two main centers for blood-services. In either one, the correct venipuncture requires the phlebotomist to have a sound knowledge of every detail of the of the procedure and blood room. This knowledge could be translated in a group of sequenced skills and techniques to obtain the best specimen. Unless all the venipuncture steps are followed, the quality of the specimen and the safety of the phlebotomy will be compromised.
In preparing for blood collection, each phlebotomist generally establishes a routine that is comfortable for him or her to follow. However, there are essential steps that are part of every successful collection procedure.
The steps could be divided into:
- Greet the patient
- Verify restrictions
- Explain procedures
- Identify patient
- Prepare order
- Assemble supplies (tubes)
- Position the patient
- Examine the patient for the blood draw
- Perform the venipuncture
- Manage tubes
- Clean area
- Dismiss patient
The phlebotomist will always use several skills when serving the patient. They can be grouped in three different modes:
Figure 9: Grouped skills diagram. Essentially, there is an apparent counter clock cycle as the activity happens, starting from social to clerical to technical skills, but overlaps may occur.
The Social mode
At the social mode, patients are often unsatisfied about their condition and take it out on the first person they see, usually the phlebotomist. The phlebotomist who maintains a high level of professionalism, should understand the patient's condition and maintain an upbeat personality. It is often said that it's the Phlebotomist who is the laboratory representative. The impression the phlebotomist makes upon the patient will reflect on the entire laboratory, and sometimes the whole hospital in general. This puts a very big strain on the phlebotomist.
The Clerical mode
At the clerical mode, writing skills are required constantly. For the Phlebotomist, the clerical skill is as simple as selecting the correct tube for the test, labeling it with the correct name, and putting down the patient's information. A misspelling could result in a law suit against the hospital and serious complications to the patient.
The Technical mode
And finally, the technical mode means obtaining blood successfully with minimal pain by taking advantage of technical skills. It consists of whatever method is used to complete the procedure: venipuncture, arterial sample, or micro-collection through skin puncture.
Currently, the Phlebotomy procedure is composed of a set of ordered activities. Variations may occur depending on the physician's personal preferences and type of test being performed. The diagram below shows in detail the sequence of activities.
Figure 10: Diagram of activities.
Once the patient enters the site, the phlebotomist has to decide what tools to use based on the test and patient characteristics. Just in terms of needles, for example, there are five types available.
Depending on the type of test, the site should be cleaned with the appropriate chemical. For example, if the phlebotomist is collecting a Blood Culture specimen, then the site and the technique must be kept as sterile as possible. The same rule applies when drawing blood for a DUI test (Driving Under the Influence of Alcohol). In this case, being sterile is not the focus here, but what chemical the phlebotomist will use to clean and prepare the site. The phlebotomist should not use an alcohol pad to clean the site because the alcohol can cause a false reading in the test.
Cleaning the site
The site should be cleaned using a circular motion, starting at the center of the site and moving outward in concentric circles. Enough pressure should be applied to remove the surface dirt, but not so much pressure as to cause a burn on the surface of the skin.
The site has to dry for about a minute. During this time, the physician should recheck the laboratory orders for the test (s) to be drawn and assemble the supplies needed to draw the sample, such as the correct color tubes, bandages and gloves (though gloves should be worn during the cleaning process).
Figure 11: Proper method for swabbing a venipuncture site, moving in an outward spiral.
The reason for waiting for the site to dry is that the residual alcohol can cause hemolysis of the blood specimen, as well as a burning pain (sensation) to the patient.
Finding the vein
Palpating the area usually helps the phlebotomist get an idea of the size, angle, and depth of the vein. The most common sites are located in the antecubital (inside elbow) area of the arm.
Figure 12: Major arm veins.
Applying the tourniquet
A tourniquet must be used to assist the phlebotomist in finding a good vein. The tourniquet is applied about 3 to 4 inches above the puncture site. It should be tight enough to stop the flow of blood in the veins but not so tight as to stop the flow of blood in the arteries.
The tourniquet should never be left on the arm for more than 1 minute due to the possibility of causing hemoconcentration (an increase of large molecules such as proteins, cells and coagulation factors). If the phlebotomist asks the patient to make a fist and unmake a fist, this should only be done a few times, as this can also cause hemoconcentration. The tourniquet should only be removed as soon as blood flow is established in the tube. The beginning phlebotomist must understand that this simple act could also cause the needle to be slightly moved causing the blood to stop, or even leak out from the puncture site.
It is recommended the tourniquet be removed just before the needle is removed from the patient. Not removing the tourniquet before the needle is removed causes blood to be forced out of the puncture site contaminating the area as well as bruising the patient's arm.
Usually, direct pressure on the puncture site will stop most external bleeding. By definition, bleeding is to lose blood from the blood vessels. The damage to a blood vessel causes bleeding, which can range from minor to life threatening. During the drawing of blood, the damage is so little that it will stop bleeding within minutes. However, puncture wounds, such a needle pick, which don't bleed very much, are dangerous because of the risk of infection.
It is important to seek medical care to prevent tetanus or other infection. The experience for the patient is not pleasant. When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Figure 13: Applying the tourniquet