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Phlebotomy Interventions that Lower Rates of Hemolysis and EDTA Contamination

Having served 20 years in the laboratory industry, I have unofficially observed that most of the errors that occur with the testing of blood samples can be avoided. The majority of the testing errors occur because of a flaw in the pre-analytical phase, which involves the time of collection, handling and transport. Hemolysis and EDTA contamination being the two greatest issues. Studies show that as much as 70% of the errors found with collected blood samples fall into these two categories.


 
Let’s first define Hemolysis and Contamination:
►  Hemolysis – “The destruction or dissolution of red blood cells, with release of hemoglobin.” This causes the damaged red blood cells to leak into the serum or plasma needed for testing. Once this occurs, the sample is no longer viable to test.
►  Contamination – “The presence of extraneous, especially infectious, material that renders a substance or preparation impure or harmful.” In this case, we are speaking specifically about the contamination of EDTA (an anti-coagulant) into other tubes whose viability becomes compromised once the EDTA is introduced.
 
The simple solution is proper training of phlebotomy staff and adherence to the policies and procedures. See below:

►  Hemolysis can be avoided by using proper collection methods including:
  • Utilizing the appropriate gauge needle for collection. *Tip* Avoid using 25g needles whenever possible.
  • Avoid excessive shaking and manipulation of tubes after collection. *Tip* Gently invert tubes 8-10 times only. Do not shake vigorously. Some tubes require no inversion or additional stimulation. Please refer to collection manuals for appropriate handling methods.
  • Avoid applying the tourniquet too tight or for too long. *Tip* The tourniquet should be tight, but not too tight. It should not be in place on the patient’s arm for longer than 1 minute.
  • When doing a finger stick, avoid excessive milking and squeezing, especially near to the puncture site. *Tip* Allow the patient to hang their arm over the collection chair to utilize the help of gravity. Wait approximately 1 second in between squeezes to allow the fingertip to fill back up with blood prior to collecting each drop.
►  EDTA contamination can be avoided simply by following the correct order of draw, which is as follows:
  • Blood Cultures - SPS
  • Citrate Tube - sterile
  • Light blue
  • Serum Tube (glass or plastic)
  • Gel Separator Tube (SST)
  • Plasma Separator Tube (PST)
  • Gel Separator Tube With Heparin
  • Heparin Tube
  • EDTA Tube
  • PPT™
  • K2EDTA with Gel
  • Fluoride (glucose) Tube
 
See the chart below for help:

 tube-draw-order.jpg
 
Scientists have determined that this order of draw significantly reduces the amount of EDTA contaminated tubes received by laboratories for testing. Following this method will keep those tubes that are collected prior to the EDTA tube safe from contamination.
 
Following proper collection methods are necessary for patient safety, sample safety and the security of the healthcare provider’s professional’s position. It is our job, as healthcare providers, to ensure accuracy, safety and proper ethical standards. 


For a complete review of proper phlebotomy procedures view Effective Blood Collection – Phlebotomy  a 3 contact hour course for nurses and other health care professionals that have the responsibility of performing lab draws.

Upon completion of this course the user will be able to:
  1. Distinguish between the different methods of blood collection.
  2. State which method to choose.
  3. Properly identify the correct order of draw and understand the difference between the additives in the tubes.
  4. Know the meaning of an anti-coagulant.
  5. Identify and correct pre-analytical complications.
  6. Determine appropriate needle insertion angles and understand the most appropriate and effective methods to use when attempting to locate a vein, and when needing to adjust.

Pedagogy guest blog written by author Souraya Pinkston.

Souraya is a Registered and Certified Phlebotomy Technician who brings forth 18 years of experience, as well as, a Certified Instructor of CPR by the American Heart Association. Originally from Cleveland, Ohio, she now resides in Las Vegas, Nevada, where she has owned and operated The Right Touch Phlebotomy Training since 2009. She is a single mother of three, currently completing her Bachelor’s Degree in Business Management, and maintains a full-time position managing a home health care agency office. Her entire medical career has been spent helping to teach and train others in developing their skills and customer service values. Her passion is teaching and helping and in her own words she is, “honored to be a part of your learning experience." 


Posted: 5/19/2014 3:57:10 PM
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