Haemolysis: The No. 1 Reason for Specimen Rejection
Download presentation given by our EPSC members at Euromedlab 2009:
- In Vitro Hemolysis: Causes, Prevalence, Effects, Measurements & Solutions. Euromedlab 2009 Innsbruck, ISW # 20.
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In vitro haemolysis has always been a major concern for clinical laboratories around the world.
Defined as red blood cell break down and the release of hemoglobin and intracellular contents into the plasma, haemolysis can seriously impact patient care and a laboratory's reputation through its affect on test results. It is important to be aware of those tests most highly affected by haemolysis1,2,3,4.
Multiple medical states can cause haemolysis in vivo5. Factors affecting haemolysis in vitro can occur beginning at the patient’s bedside and continue through analysis and storage. Factors vary depending upon the patient’s condition (fragile veins), the skill of the person collecting the sample (training), and the local environment (temperature, length of transport).
The major causes of haemolysis are improper specimen collection and handling6,7. (These procedures are normally not under the control of the laboratory; even so, rejected samples and inaccurate test results are often attributed to laboratory errors). A great deal of knowledge, skill, and experience is required to collect a quality specimen that yields desired results.
Gathering data in your healthcare organisation will help identify the areas where haemolysis occurs most frequently (emergency room, intensive care unit, maternity), which can, in turn, guide further analysis about why it is occurring. Once these elements are known, practices and procedures can be implemented to dramatically reduce haemolysis and avoid erroneous laboratory results affecting patient care and increasing laboratory costs.
Practices & Procedures to Reduce In Vitro Haemolysis:
- Carefully review practices and procedures when collecting blood samples from patients with fragile veins, such as geriatric & oncology patients.
- Carefully review practices and procedures when collecting blood samples from cathetherised patients8 such as those in emergency, intensive care, and maternity departments.
- Key aspects to focus on during collection include9: Avoid collection from a hematoma site, prolonged tourniquet time, and equipment and connections that may lead to turbulent blood path; use appropriate techniques for syringe collection; ensure correct tube volume is collected; do not subject a sample to vigorous mixing.
- Define practices and procedures for sample transportation to preserve appropriate temperature, and to avoid prolonged transportation time and excessive sample agitation.
- Centrifuge within an appropriate time of collection10, aliquot supernatant (serum or plasma) from red cells unless using a gel based separator tube.
- Ensure appropriate centrifugation conditions and pay particular attention to g force, spin time and temperature.
- Review patient history for factors that may affect in vivo haemolysis: metabolic disorders (liver disease, sickle cell anemia), drugs (analgesics, antimalarial drugs), mechanical heart valve, and haemolytic anemia third degree burns and infections5
- When possible use analytical method uneffected by haemolysis.
- Consider using the instrument features such as the haemolysis index to determine the level of haemolysis in samples. This can be used to monitor sample quality over time and provide information about problem areas to focus on for improvement.
Learn more about this topic:
- Effects of Preanalytical Variables on Clinical Laboratory Tests, 2nd Edition. Young D.S. 1997, AACC press.
- Graphical Comparisons of Interferences in Clinical Chemistry Instrumentation. Melvin R. Glick, Kenneth W. Ryder, and Sheila A. Jackson. Clinical Chemistry 1986; 32(3): 470-475.
- Influence of hemolysis on routine clinical chemistry testing. Lippi G, Salvagno GL, Montagnana M, Brocco G and Guidi GC. Clin Chem Lab Med 2006; 44(3): 311-316.
- Clinical Diagnosis and Management by Laboratory Methods. Henry JB, ed. Todd-Sanford-Davidsohn Vol 1. 16th ed. Philadelphia, PA: WB Saunders Co; 1979:1005-1007.
- “Oh, No! It’s Hemolyzed!” What, Why, Who, How? Lemery LD. Advance for Med Lab Prof. 1998;24-25.
- Elevated serum potassium values: the role of preanalytic variables. Stankovic AK, Smith S. Am J Clin Pathol. 2004;121(suppl 1):S105-S112.
- Hemolysis in serum samples drawn by emergency department personnel versus laboratory phlebotomists. Burns ER, Yoshikawa N. Lab Med. 2002;33:378-380.
- Procedures for the Collection of Diagnostic Blood Specimens by Venipuncture; Approved Standard 6th ed. National Committee for Clinical Laboratory Standards. Wayne, PA: National Committee for Clinical Laboratory Standards; 2007. NCCLS Document H3-A6.
Procedures for the Handling and Processing of Blood Specimens; Approved Guideline 3rd ed. National Committee for Clinical Laboratory Standards. Wayne, PA: National Committee for Clinical Laboratory Standards; 2010. NCCLS Document H18-A4.
Last modification on 5 July 2012