Minimizing Pre-Analytical Variability During Venipuncture, Urine Sample Collection, and Sample Processing

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Jack A. Maggiore, PhD, MT(ASCP)
Reviewer: Lisa Dewey, MT(ASCP)

Clinicians make patient care decisions based on the results of laboratory testing. Pre-analytical errors can have a significant negative impact that prevents the delivery of quality patient care. These negative outcomes can range from unnecessary redraws and delayed results, to improper treatment, misdiagnosis, and even death. This course is intended to emphasize the pre-analytical variables that must be controlled during venipuncture and urine collection procedures in order to ensure the quality reporting of laboratory test results.

Continuing Education Credits


  • Categorize the phases of clinical laboratory testing as pre-analytical, analytical, and post-analytical.
  • Identify several of the pre-analytical variables associated with patient preparation.
  • Explain the phlebotomist’s role in minimizing pre-analytical variability associated with venipuncture and urine sample collection.
  • Specify the most frequently encountered sources of hemolysis.
  • Recognize potential sources of pre-analytical variability associated with sample handling and transportation.
  • Determine the common pre-analytical causes of unanticipated laboratory results.

Course Outline

  • Phases of Clinical Laboratory Testing
      • The Testing Process
      • The Pre-analytical Phase and Importance of Minimizing Variability
      • Why is it Important to Minimize Pre-Analytical Variability?
  • Patient Identification
      • Proper Patient Identification is Crucial
  • Variables Related to Patient Preparation
      • Fasting
      • Medications and Supplements
      • Hydration and Dehydration
      • Sleep
      • Stress
      • Stress affects the production of many hormones and neurotransmitters and may impact some laboratory test values. Which of the following methods will h...
  • Variables Related to Blood Sample Collection
      • The Blood Collection Process
      • Patient Position
      • Venipuncture Technique
      • Site Cleansing/Disinfecting
      • Needle Gauge
      • Tourniquet
      • Tube Mixing
      • Tube Type and Collection Volume
      • Order of Draw
      • Traumatic Draw
      • Intravenous Solutions
      • Which of these variables related to the collection of blood may falsely increase the plasma potassium level, if the potassium sample is collected usin...
  • Variables Related to Urine Sample Collection
      • Preservatives Used for Urine Collection
      • Timed Urine Samples
      • Incomplete Urine Collection
      • Dilutional Effect on Urinary Markers
      • Contamination of Urine Samples
      • A 24-hour urine collection should include the first morning void on day one of the collection and the first morning void on day two of the collection.
  • Variables Related to Sample Transport
      • Transport Time
      • Transport Temperature
      • Mechanical Transport
      • When the transport time may be prolonged for circumstances beyond the control of the laboratory, the integrity of the sample may be preserved by keepi...
  • Variables Related to Sample Handling
      • Time Between Collection and Centrifugation
      • Incomplete Gel Barriers
  • Variables Related to Sample Preparation
      • Centrifugation Speed
      • Centrifugation Temperature
  • Variables Related to Sample Storage
      • Storage Time
      • Storage Temperature
      • Light-Sensitivity
      • Freeze-Thaw Cycling
      • Which analyte may be falsely decreased due to a delay in transport time to the laboratory?
  • The Matrix Interferents
      • The Matrix Interferents
      • Hemolysis
      • Lipemia
      • Icterus
      • Viscosity
      • Among the most common matrix interferents in blood, which is considered to be the most preventable with precautions taken during sample collection and...
  • Investigating Unanticipated Analytical Findings
      • Investigating Unanticipated Analytical Findings
      • Case Study: Highly-Elevated Serum Potassium
      • Investigation: Highly-Elevated Serum Potassium
      • Case Study: Severely Decreased Serum Calcium
      • Investigation: Severely Decreased Serum Calcium
      • Case Study: Critically Low Serum Glucose
      • Investigation: Critically Low Serum Glucose
  • References
      • References

Additional Information

Level of instruction: Basic

Intended Audience: This course is intended for phlebotomists, phlebotomy supervisors, patient care coordinators, medical laboratory technicians, medical laboratory scientists, laboratory supervisors, managers and directors. This course is also appropriate for medical laboratory science students and pathology residents.

Author Information: Jack A. Maggiore, PhD, MT(ASCP) serves as the Assistant Laboratory Director of Chemistry and is Head of Research and Development at Doctor's Data, Inc. in Saint Charles, Illinois. Dr. Maggiore is a medical technologist, certified by the ASCP, with a Master of Science in Clinical Chemistry and Doctorate in Pathology from the University of Illinois. His expertise includes clinical instrumentation, method development and validation, quality assurance, medical device clinical trials, and scientific regulatory affairs. His clinical research interests include development of novel biomarkers for chronic diseases using blood spots and other non-conventional samples. Dr. Maggiore holds several medical device patents, has authored more than fifty peer-reviewed and invited publications and textbook chapters, and has presented his research findings at international scientific society meetings. Dr. Maggiore's mission is to work with health care professionals to empower consumers to take a more active role in their health maintenance.

Reviewer information: Lisa Dewey, MT(ASCP) is the Quality Manager at Doctor's Data, Inc. and has been a medical technologist since 1990. She obtained a BS in Clinical Laboratory Science from the University of Illinois at Chicago. Lisa has experience working in various specialties in hospital and clinic laboratories, research & development, laboratory management, and a commercial laboratory specializing in dried blood spot testing.

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