CAP Pro Course - Hematology - White Blood Cells (2026 & 2027)

Author: Margaret A. Reinhart, MS, MLS(ASCP)
Reviewer: Laurie Bjerklie, MA, MLS(ASCP)CM and Joshua J. Cannon, MS, MLS(ASCP)CMSHCM

Continuing Education Credits

Objectives

  • Identify preanalytic variables that may adversely affect the accuracy of automated white blood cell counts or manual differentials.
  • Identify non-white blood cell particles that may interfere with automated white blood cell counts and interpret general instrument flagging messages.
  • Differentiate mature, immature, and abnormal myeloid cells on peripheral smears and correlate findings with basic clinical conditions.
  • Differentiate mature, immature, and abnormal lymphoid cells on peripheral smears and correlate findings with basic clinical conditions.

Course Outline

  • Identify preanalytic variables that may adversely affect the accuracy of automated white blood cell counts or manual differentials.
      • Sample Collection Requirements for Automated White Blood Cell Analysis
      • Time and Temperature Impacts on WBC Stability
      • Alternative Anticoagulant Use in Specimen Collection
      • Degenerative WBC Changes Observed on Manual Differential Smear
      • A specimen collected in sodium citrate anticoagulant has an absolute lymphocyte count of 5.0 X 109/L on the automated CBC results. Which of the follow...
      • Upon reviewing a sample for manual differential, you've observed this stained structure in multiple fields. How should this cell be identified, and wh...
      • The structures indicated by the arrows were seen on a peripheral blood smear stained with Wright stain. What is the most appropriate action to take be...
  • Identify non-white blood cell particles that may interfere with automated white blood cell counts and interpret general instrument flagging messages.
      • Platelet-associated Interference: Platelet Clumps
      • Platelet-associated Interference: Megakaryocytes
      • Platelet-associated Interference: Giant Platelets
      • Particle Interference: Lyse-Resistant Red Blood Cells
      • Particle Interference: Nucleated Red Blood Cells (nRBCs)
      • Particle Interference: Cryoglobulins
      • Instrument Flagging: Manufacturer-defined Flags
      • Instrument Flagging: User-defined Flags/ User-adjustable Manufacturer-defined Flags
      • Automated CBC results for an adult male include a flag that indicates the presence of nRBCs, but your basic hematology analyzer does not report the nR...
      • Your hematology analyzer has generated a flag for “WBC interference.” Smear review reveals the presence of an unusual structure. The patie...
      • When reviewing a smear of a specimen that has generated multiple instrument flags, you observe the presence of nRBCs. What is the correct WBC count to...
      • The cell indicated by the blue arrow in the image on the right is observed throughout a peripheral smear on a patient with a myeloproliferative disord...
  • Differentiate mature, immature, and abnormal myeloid cells on peripheral smears and correlate findings with basic clinical conditions.
      • Introduction
      • Mature Myeloid Cells
      • Immature Myeloid Cells: Granulocytes
      • Immature Myeloid Cells: Monocytes
      • Abnormal Myeloid Cells in the Peripheral Blood: Immature Cells
      • Abnormal Myeloid Morphology: Benign Changes
      • A 45-year-old male patient was admitted to an academic medical center upon his doctor’s referral. A stat hematology workup and consultation were...
      • The following are results of an automated CBC from a 71-year-old male patient admitted to your hospital after a physician referral. The patient had co...
      • You are performing a manual differential on a patient specimen that generated an immature WBC flag. While reviewing the smear, you see an immature-loo...
      • A medical laboratory scientist was performing a differential on a patient from the walk-in clinic presenting with a fever, fatigue, malaise, and short...
  • Differentiate mature, immature, and abnormal lymphoid cells on peripheral smears and correlate findings with basic clinical conditions.
      • Mature Lymphoid Cells
      • Variations in Mature Lymphocyte Morphologies
      • Immature Lymphoid Cells
      • Abnormal (Malignant) Lymphocyte Morphologies
      • Abnormal (Malignant) Lymphocyte Morphologies, continued
      • A medical laboratory science student finds the cells indicated by the arrows in the image on the right. What is the appropriate classification the stu...
      • A blood sample is received in the laboratory for a CBC on a 65-year-old male patient with chief complaints of weakness and fatigue. The WBC count of 2...
      • You have just evaluated a peripheral blood smear from a 12-year-old male patient recently admitted to your hospital. Which CBC instrument results are ...
  • References
      • References

Additional Information

Level of Instruction: Intermediate
Intended Audience: Medical laboratory scientists, medical laboratory technicians, laboratory supervisors, and laboratory managers. This course is also appropriate for MLS and MLT students and pathology residents.
Author Information: Margaret Reinhart, MS, MLS(ASCP) is a Senior lecturer in Biological Sciences at the University of the Sciences in Philadelphia PA where she teaches hematology, clinical immunology, parasitology, and other related courses. She was the MLS Program Director there for 30 years. She is also adjunct instructor in Hematology at Pennsylvania Hospital, Philadelphia PA. She holds a Masters Degree in Biology and in Health Care Administration.
The author has no conflict of interest to disclose.
Reviewer Information:
Laurie Bjerklie, MA, MLS(ASCP)CM is currently an Education Developer for MediaLab by Vastian. She earned a B.S. in Medical Laboratory Science from the University of North Dakota and an M.A. in Curriculum and Instruction from Saint Xavier University. She has over 15 years of experience in higher education and has held program director and faculty positions in both MLT and MLS programs.
Joshua J. Cannon, MS, MLS(ASCP)CMSHCM received his Bachelor of Science and Master of Science in Medical Laboratory Science from Thomas Jefferson University in Philadelphia, PA. He holds Medical Laboratory Scientist and Specialist in Hematology certifications through the ASCP Board of Certification. He was a professor at Thomas Jefferson University for seven years before transitioning into his current role as Education Developer at MediaLab by Vastian. His areas of expertise and professional passions include clinical hematology and interprofessional education.

This course is part of the CAP Competency Assessment Hub.

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