Module 3E: Phlebotomy Flashcards
Phlebotomy
The process of withdrawing blood from a vein for laboratory testing
When having blood work for a lipid panel, how can eating a meal prior to having blood drawn affect blood test results?
Patients should fast prior to having a lipid panel. If the patient ate a meal prior to having blood drawn, the test values would likely detect fats from the food and the results would indicate elevated lipid levels.
Fasting
The absence of eating food and sometimes drinking.
Laboratory directory
A catalog of information regarding laboratory tests with up-to-date test menus; testing information; specimen collection requirements; and storage, preservation, and transportation guidelines.
Patient positioning for blood draw
- Seat the patient in a comfortable, well-lit area.
- Position the patient with their arm extended out. If a phlebotomy chair with an extended arm rest is not available, have the patient make a fist with the opposite hand and place it behind the elbow of the arm being used for the procedure. This ensures the arm will stay straight and stable during the procedure.
For pediatric patients, a support person could assist in holding the patient’s arm still to avoid injury. Effective communication and accurate skills are necessary when dealing with children.
What is the first step to beginning any phlebotomy procedure?
Obtaining the provider’s order for laboratory testing. Review the provider’s order for blood work to determine what tests need to be completed. Venipuncture procedures should not be performed on patients without a provider’s order.
Laboratory requisition form includes….
- Ordering provider’s name and contact information
- Test and test code (unique to each lab, usually on the requisition or in the laboratory reference manual)
- Diagnosis code that correlates with the tests being ordered (ICD-10)
- Special specimen requirements, such as fasting
- Patient demographics
- Insurance or other billing information
Supplies and equipment needed for blood draws
Vary depending on what type of venipuncture procedure is being performed. In general, supplies needed include the following.
Alcohol wipes
Gauze
Adhesive bandages
Biohazard sharps container
PPE, including disposable gloves
Tourniquet
Collection tubes
Needle system
3 Types of Needle System
- Evacuated System
- Winged Infusion Set, or Butterfly System
- Needle Syringe System
Evacuated Needle System
This is the most commonly used system.
This system consists of a double-pointed needle, a plastic needle holder/adapter, and collection tubes.
The collection tube system creates a slight vacuum that helps transport the blood from the vein into the collection tube when penetrated.
Using this method helps to obtain multiple tubes of blood with one venipuncture stick.
Vacutainer needles are typically 20 to 22 gauge with a needle length of ¾ inch to 1 ½ inches. The length and gauge of the needle will depend on perceived depth of the vein and the size of the patient.
Butterfly Needle System (Winged Infusion Set)
The winged infusion set consists of flexible wings attached to a needle with 5 to 12 inches of flexible tubing that connects the needle to the collection device.
This method is best used for patients who have small or fragile veins. This technique tends to cause less trauma or bruising to the patient.
Butterfly needles are typically 21 to 23 gauge with a needle length of ½ to ¾ inch. The length of the needle will depend on the size of the patient.
Needle Syringe System
A needle and syringe can be used to draw blood from a vein.
This is not ideal because only a small amount of blood can be obtained with this method.
One advantage is the amount of suction can be controlled by the plunger of the syringe instead of the vacuum method.
Generally, a 16-gauge injection needle and syringe are used with this method.
Parts of the Needle
- Lumen: hollow space inside the needle. Also referred to as the gauge. The larger the gauge number, the smaller the diameter.
- Bevel: shaft at the end of the needle that creates a point.
Arranging Supplies For Blood Draw
All necessary phlebotomy supplies, including the sharps container for needle disposal, should be within reach.
During the procedure, hold the needle in the dominant hand and avoid switching hands once the skin has been penetrated.
This will require the remaining supplies be set up on the opposite side of the dominant hand. Arrange the supplies in the order needed to use them, including placing the tubes in the correct order of draw. Whenever possible, place the sharps container on the dominant side as well.
Components of blood
plasma, white cells, red cells, and platelets
Plasma
The liquid portion of the blood; mainly made of water; contains proteins, electrolytes, gases, some nutrients, and waste products; is required to recover from injury, distribute nutrients, and remove waste from the body.
The liquid portion of the blood obtained after centrifuging. The blood specimen must be collected in a tube containing anticoagulant. There will be three layers after the sample has been centrifuged: plasma (top layer), buffy coat (middle layer), and red blood cells (bottom layer).
White Blood Cells
Responsible for defending the body against bacteria and viruses
Red Blood Cells
Responsible for carrying oxygen to the tissues throughout the body and carbon dioxide from the body to the lungs.
Platelets
Responsible for limiting the loss of blood when a blood vessel is damaged or leaking.
Serum
The liquid portion of the blood obtained after a serum sample tube has clotted and centrifuged.
Clotted Blood
This is obtained when blood is drawn in a tube that does not contain an anticoagulant.
Whole Blood
Obtained when a tube is used with an anticoagulant, which inhibits blood clotting.
Order of Draw for Venipuncture
- Yellow top tube or blood culture bottles
- Light blue
- Red
- Red/gray marbled
- Green
- Green/gray marble
- Lavender
- Gray
Why is draw order of vacuum tubes important?
The order of blood tube draw is critically important to avoid errors. During the blood draw process, the additive from one tube can carry over to another and affect test results.
Yellow Top Tube
Additive: Sodium polyanethol sulfonate; prevents blood from clotting and stabilizes bacterial growth
Laboratory Use: Blood or body fluid cultures
Number of Inversions: N/A