In the Beginning There Was Blood: Importance of Peripheral Blood Smears


Complete blood count is one of the most common tests ordered by healthcare providers. Careful morphologic review of blood smears can reveal important diagnostic clues and help with the patient’s management. This lecture, presented as a series of vignettes, will focus on specific morphologic findings in peripheral blood samples with neutrophilia, monocytosis and lymphocytosis. In addition, the lecture will point out the important morphologic features associated with neoplastic, rather than reactive, conditions.

Originally presented on February 5, 2023, in Park City, Utah.

Lecture Presenter

Olga Pozdnyakova, MD, PhD

Olga Pozdnyakova, MD, PhD

Associate Pathologist
Brigham and Women's Hospital
Associate Medical Director of the Clinical Hematology Laboratory
Brigham and Women’s Hospital
Medical Director
Physicians Diagnostic Labs
Associate Professor, Pathology
Harvard Medical School

Dr. Olga Pozdnyakova is an associate professor of pathology at Harvard Medical School and a diagnostic hematopathologist at Brigham and Women’s Hospital/Dana Farber Cancer Institute. She serves as the medical director of the Hematology Laboratory at Brigham and Women’s Hospital and Physician Diagnostics Labs at the Brigham Health Harbor Medical Associates. Dr. Pozdnyakova is an author of over 90 peer-reviewed publications and reviews. She has authored chapters on the topic of myeloid neoplasm in several fundamental pathology textbooks, such as Diagnostic Histopathology of Tumors, Wintrobe’s Atlas of Clinical Hematology, Diagnosis of Blood and Bone Marrow Disorders, and Diagnostic Bone Marrow Hematopathology, and is a coauthor of the textbook Hematopathology: A Volume in the High Yield Pathology Series. She serves as a vice-chair of the College of American Pathologists Clinical Hematology and Microscopy Committee. Dr. Pozdnyakova has lectured on various topics at numerous national and international pathology meetings and educational courses.


After this presentation, participants will be able to:

  • Correctly identify white blood cells' morphologic abnormalities in peripheral blood smears
  • Formulate an appropriate and comprehensive differential diagnosis for abnormal morphologic findings that includes neoplastic and reactive processes
  • Describe the role of ancillary testing, especially flow cytometry, in a work-up of patients presenting with abnormal peripheral blood morphologic findings

Sponsored by:

University of Utah School of Medicine, Department of Pathology, and ARUP Laboratories