Understanding the complete blood count with differential

J Perianesth Nurs. 2003 Apr;18(2):96-114; quiz 115-7. doi: 10.1053/jpan.2003.50013.


The complete blood count (CBC) with differential is one of the most common laboratory tests performed today. It gives information about the production of all blood cells and identifies the patient's oxygen-carrying capacity through the evaluation of red blood cell (RBC) indices, hemoglobin, and hematocrit. It also provides information about the immune system through the evaluation of the white blood cell (WBC) count with differential. These tests are helpful in diagnosing anemia, certain cancers, infection, acute hemorrhagic states, allergies, and immunodeficiencies as well as monitoring for side effects of certain drugs that cause blood dyscrasias. Nurses in the perianesthesia arena are frequently challenged to obtain and evaluate all or parts of the CBC as a part of the patient's preoperative, intraoperative, and postoperative assessments. An enhanced understanding of this laboratory test is essential to providing quality care.

Publication types

  • Review

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Blood Cell Count / methods*
  • Child
  • Erythrocyte Indices
  • Female
  • Hematocrit
  • Hemoglobins / analysis
  • Humans
  • Male
  • Mass Screening / methods
  • Middle Aged
  • Nursing Assessment / methods
  • Patient Selection
  • Postanesthesia Nursing / methods
  • Reference Values


  • Hemoglobins