Understanding the Causative Issues of Pre-Analytic Hemolysis in the Health Care Setting.
Pre-analytical hemolysis affects only the red blood cells, or erythrocytes, prematurely destroying them. The typical RBC lives approximately 120 days and then the cell wall ruptures, releasing hemoglobin and cell fragments which are poured out into the blood plasma, and is a normal occurrence within the body to be recycled back to the bone marrow maintaining homeostasis. During a blood draw, pre-analytic hemolysis can be created and is detrimental to laboratory results. Erythrocyte cell wall membranes rupture very easily, not only spilling hemoglobin but elevating serum potassium, bilirubin, acid phosphate, zinc, magnesium, albumin, creatine kinase CK, and also cause an elevation in D-dimer results. (3) On average, it has been proven that pre-analytic hemolysis can interfere with 39 different blood results. Phlebotomists have a great appreciation and even a greater understanding of this concept as opposed to healthcare personnel who routinely draw blood but are not certified phlebotomists. Certified laboratory phlebotomists utilize specific collection practices, protocols and procedures in order to help prevent pre-analytic hemolysis. (3,4) The breakage of red blood cells or "lysis" is easily detected in the lab, whereas the spilled hemoglobin turns blood plasma pinkish to red dependent on the concentration of RBCs lysed or hemolized in the sample. (4)
Because it is poorly understood, reducing the occurrence of pre-analytic hemolysis of specimens drawn in the healthcare environment is a consistent nemesis that is experienced by healthcare personnel who routinely draw blood, but are not professional laboratory phlebotomists. The misconception may stem from the fact that healthcare personnel may not be properly trained in the art and science of correct and consistent blood draw protocols and procedures as laboratory phlebotomists are. Healthcare personnel either do not understand, or simply underestimate the conditions and the complexities of proper procedure, proper protocol, and proper training to draw blood accurately and correctly. (5)
The concept of phlebotomy best practices as established by the World Health Organization (WHO) is now being introduced and becoming a growing focus for hospitals across the nation. The best practices concept is rapidly bringing to light an awareness of what can happen when collectors of blood severely underestimate and misunderstand blood specimen collecting practices and procedures. (6) There is a comprehensive training program given to phlebotomists to promote and provide a best practice standard of care. (6)
The use of a standard protocol for blood draws can reduce the rate of pre-analytic hemolysis by more than 7-fold. (2) The rate of hemolysis from collectors of blood other than phlebotomists was shown to be on average 12.4 percent as compared to 1.6 percent drawn by phlebotomists. (2)
The American Society for Clinical Pathology has established a benchmark of 2 percent or lower for hemolysis rates in laboratory blood samples, and is also the standard of care for laboratory phlebotomists. (3)
According to Ana K. Stankovic, MD, PhD, MSPH, WW, vice president of medical and scientific affairs and clinical operations at BD Diagnostics, most all non-lab phlebotomist personnel, (healthcare workers) while during their preceptorships, are not properly trained in the use of an optimal precise collection technique ideal to achieve proper specimen collection results. (5) This lack of proper training opens up a Pandora's box of wrongly handled procedures such as the use of inadequate devices or needles, incorrect order of draw, prolonged tourniquet times, collection of unsuitable samples either quantity or quality, or improper transportation and storage. Phlebotomy study results have shown that lab based phlebotomists commit fewer errors in identifying, labeling and drawing blood samples than healthcare personnel. Using phlebotomists on the floors and in the ER can reduce the rate of hemolysis by 20 fold. (5)
The emergency department no doubt has to deal with extreme difficulties with patients on a daily basis such as inappropriate or problematic patients, patients acutely injured, or chronically sick and dehydrated which make them less than ideal for a quality blood draw, coupled with the circumstances for a stat draw. All healthcare staff who avoid placing the IV catheter in the antecubital fossa believing that they are decreasing the probability of an obstruction of the infusion when the patient bends their arm and draw blood thru it run the increased risk of hemolysis. (2)
There may be times when the circumstances dictate that healthcare personnel draw blood from the distal aspect of the arm. Chi-Square Analysis concluded that hemolysis occurred less often if blood was drawn from the Antecubital fossa (2). Chi-Square analysis testing also concluded that drawing blood thru a plastic catheter drastically increased hemolysis rates as compared to using metal needles or butterflies. (2) If IV catheters must be used for blood draw, Chi-Square analysis concluded hemolysis rates in catheter size comparison were less common when using a larger 20 gauge plastic catheter and more common when using a 22 gauge or smaller plastic catheter. (2) Comparatively, the most detrimental practice is to draw blood thru a plastic catheter smaller than 20 gauge placed distal to the antecubital fossa, and then transport it to the lab via a pneumatic tube system. (2) Blood tube specimens should ideally be transported to the lab by hand in a vertical position. (2)
Phlebotomists are specifically trained in the practice of drawing blood utilizing a straight needle for all venipunctures in their blood draw techniques. (2, 3) Laboratory phlebotomists have a defined set of in house polices, and best care practices that directly correlate specific ways to impact hemolysis reduction rates. (3)
Hemolized blood samples account for approximately 40 to 70 percent of all unsuitable collected blood samples. (3) Pre-analytic hemolysis is 5 times more likely to be the direct culprit resulting in unsuitable blood specimens. (3) Pre -analytic hemolysis is the main reason for blood re-draws basically giving rise to unreliable lab results requiring a re-draw, and of course a delay in treatment, a delay in patient care. (2, 3, 4) Studies have shown that 46 to 56 percent of all laboratory blood sample inaccuracies occur as a direct result of the collection process and transport process. (6) It cannot be stressed enough that hemolized blood is the most common reason for specimen rejection rates in the laboratory setting. (6) Winchester Massachusetts Medical Center has made great strides towards achieving a momentous result of promoting a collaboration between the laboratory phlebotomists, nursing, and ancillary staff in order to properly obtain lab specimens yielding optimal lab results. (6)
The reasons for hemolysis can be explained through evidence-based data. Outwardly, hemolysis in and of itself can occur with certain disease processes such as autoimmune disease, hemolytic anemia, poisonous snake bites and severe burns, or hemolysis can occur as a result of a hemolytic transfusion reaction within 24 hours of a blood transfusion. (4) More often than not, hemolysis occurs as a direct result of improper specimen collecting and improper specimen handling and is properly termed pre-analytic hemolysis. (4)
A complete systemic approach on how to reduce pre-analytic hemolysis rates would be an absolute asset to any healthcare institution or setting. Breaking down the barriers to pre-analytic hemolysis can be thought of as a process of categorizing each step of a proper blood draw, starting with the tourniquet.
Venipuncture tourniquets constrict blood vessels which in turn increase hemolysis rates. (3) It has been recommended, that tourniquet times should be no longer than 1 minute in duration. If it takes longer than 1-minute to access a vein, release the tourniquet for two minutes before reapplying it. A prolonged tourniquet time, or tourniquet interference over 1-minute, begins causing interstitial fluid to leak into the surrounding tissue, promoting a pre-analytic hemolysis scenario. (3, 4)
As trivial as it may sound, when using isopropyl alcohol to prep the site, be aware that isopropyl alcohol can damage the red blood cell membrane causing lysis. It is therefore recommended that prior to the initial blood draw, the best practice is to allow alcohol to air dry completely. (4)
Collecting procedures should be modified for a best practice procedures. Using an IV catheter for blood draw is not a best practice. IV starts should never be the first choice for collecting blood. (3) IV catheters are not designated for blood withdrawal. The catheter sheath flaps inwardly when syringe suction is applied, syringe suction reduces inner pressures within the inner lumen of the catheter creating a partial collapse, thus causing an internal "flapping motion" which leads to hemolysis. Always make a conscious effort to avoid drawing from catheters and lines. Catheters and lines are primarily designed to function efficiently delivering to, and not to drawing from. (1, 4)
Syringes should be used with caution, pulling too fast, or pulling too hard on the plunger will always exert pressures much greater than that of the standard vacutainer tube. Drawing blood samples from a syringe causes shearing forces and turbulence that has the capability to destroy the red blood cell membrane making hemolysis more prevalent and unavoidable. (4) Syringes can also cause an uneven suction/pull through the needle, whereas vacutainers deliver a more constant even suction/pull with a fixed pressure. It is has been established that syringes cause a greater pressure differential than a vacutainer. (1, 3, 4)
The use of straight needle venipunctures instead of IV starts is more effective at reducing hemolysis rates and is recommended as evidence-based best practice. (3) If IV starts must be used for blood draw, hemolysis rates were shown to be reduced if the IV catheter was placed in the antecubital site. (3)
Vacutainer tubes are best for blood draw collection, using conventional venipuncture methods. A study was done comparing catheter and syringe draws to vacutainer tube and conventional blood draw methods and found 50 percent of all blood draws with syringe and catheter hemolized, whereas no specimens collected conventionally hemolized. (1)
Choosing the proper site for blood withdraw also affects hemolysis rates. Always draw from the antecubital region of the arm with a 20 gauge needle for less chances of hemolysis. (2, 4) The antecubital site is the best choice because it provides access to larger veins, while using the optimal choice of a 20 gauge needle affording less opportunity for vessel collapse. (2, 3, 4) On the other hand, distal arm venous anatomy yields smaller veins with an increased probability of vessel collapse. (3) Ultimately, there will be times when other regions of the arm other than the antecubital are needed to draw blood from, and typically being more distal to the antecubital fossa; however, this will unfortunately increase the chances of hemolysis. (4) It should also be noted that blood specimen contamination can occur when drawing blood distal to the antecubital fossa which has an established running IV. (6)
While in the antecubital fossa of the arm, correct vein selection is also a consideration for proper blood draw technique affording an optimal result. Laboratory phlebotomists are trained in the facets of an actual order of intention for blood draw where the choices are as follows. (6) The median cubital vein is the first and best choice because it is largest and closest to the surface of the skin. The second choice is the cephalic vein, and third choice is the basilic vein. (6) A common nerve injury from a simple blood draw is injury to the antebrachial cutaneous nerve which primarily occurs when "fishing" for the basilic vein. (6)
The use of a warm compress to "warm the site" is recommended to aid in increase of blood flow to the venipuncture site, thus preventing the need to "milk-the-site." The act of milking the site is another common issue resulting in the increased chances of pre-analytic hemolysis. (4) Allow for correct needle placement, not only is the correct vein important, but the way the needle enters the vein is also important. (4) If the bevel of the needle becomes overcrowded by the inner wall of the vein, secondary to poor needle placement inside the vein, or improper angle of insertion of the needle, creates a dramatic fluidic shear force on the red blood cell walls as they traverse the needle which would be evident by a slower than normal blood withdraw. (4)
Needle size can also affect hemolysis; using too small a needle will equate to excessive vacuum force thereby yielding a greater fluidic shear experience, and too large a needle causes shear stresses from an increase in turbulence. (4) The 20 gage needle is the first choice, the 21 gauge is the second choice, and the 22 gauge should be the last choice. (3, 4)
The vacutainer tubes themselves ultimately should be of a partial- fill vacuum type tube as opposed to a full vacuum type tube. The reason is that partial fill vacuum tubes have less of chance of a turbulent blood fill, and therefore less of a chance of pre-analytic hemolysis. (3)
Vacutainer tubes volume also plays a role in hemolysis; the fuller the vacutainer tube with blood, the less chance of pre-analytic hemolysis. (2) Filling the vacutainer tube to the correct volume plays a role in preventing hemolysis. Under filling vacutainer tubes that contain an anti-coagulant results in a higher concentration of additive in the blood sample promoting hemolysis. It is recommend to make use of a smaller tube for more difficult blood draws. (4) Most health care givers fail to recognize or understand that vacutainer blood tubes after a draw should always be kept in a vertical position for storage and transport to the lab. (4)
Hemolysis can also occur from mechanical trauma as well, as in transporting blood via pneumatic tube systems, where variations of length of tube system, speed o tube system, and number of turns within the tube system all affect hemolysis. (2)
(1) Savory, J. PhD. Hemolysis of Specimens Drawn in the ER Laboratory Medicine Vol. 27 number 12, 1996 https://acedemic.oup.com/lamed/article-abstract Accessed Sept. 23, 2017.
(2) Burns, R. E. MD. Hemolysis in Serum Samples Drawn by Emergency Department Personnel verses Laboratory Phlebotomists Laboratory Medicine Vol. 33 number 5, 2012 https://acedemic.oup.com/labmed/article-abstract33/5/378 Accessed Sept. 23, 2017.
(3) Heyer, J.N. Effectiveness of Practices to Reduce Blood Sample Hemolysis in EDs: 2012 HHS Public Access http://www.ncbi.nlm.nih.gov.
(4) Accessed Sept. 23, 2017.
(5) Ally, A. Avoiding hemolysis in Blood Sample Collecting and Processing Dec. 8, 2015. http://blog.fisherbiodservices.com. Accessed Sep. 23, 2017.
(6) Appald, K. Solving Phlebotomy Problems Article 354. Aug. 2009. http://writenowservices.com
(7) Accessed Sep. 23, 2017.
(8) Lusky, K. Rooting Out Invisible Blood Collection Errors Dec. 2003. http://cap.org.apps/portales/contentviewer CAP Today PFD 166 Accessed Sep.23, 2017
Michael Shymko, AAS, RT[R] ARRT, Staff Radiologic Technologist, Hackensack Meridian Health System Ocean Medical Center; Instructor, Medical Assistant Program, Brookdale Community College, Freehold, NJ; Clinical Liaison Radiography Program, Middlesex County College, Edison, NJ
Tina Shymko, RN CCRP CPEN CCT Program Director & Instructor, Medical Assistant Program and Instructor, EKG & Monitor Technician Certificate Program, Brookdale Community College, Freehold Campus, Freehold, NJ; Cardio Diagnostics, Hackensack Meridian Health System Southern Ocean Medical Center
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|Title Annotation:||Article 445 1 Clock Hour|
|Author:||Shymko, Michael; Shymko, Tina|
|Publication:||Journal of Continuing Education Topics & Issues|
|Date:||Jan 1, 2018|
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