Understanding the CBC ( Complete Blood Count )

Understanding the CBC ( Complete Blood Count ) is organized by RnCeus Interactive.

Expiration Date: Feb 07, 2023

Description:
The complete blood count, or CBC, is one of the most frequently ordered laboratory tests. The CBC is a valuable screening test that provides important diagnostic information. Tests measured as part of the CBC determine the number, type, percentage, concentration, and quality of various blood cells. These tests are performed simultaneously, usually in less than a minute, using an automated hemotology analyzer. In some situations, such as very low or very high results, or when an abnormal cell population is identified, manual celll counts or manual microscopic examinations are done.

Tests usually included in a CBC include:
• White blood count (WBC)
• Red blood cell count (RBC)
• Hematocrit (Hct)
• Hemoglobin (Hb or Hgb)
• Red blood cell indices:(mean corpuscular volume [MCV], mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration [MCHC]
• A differential white blood cell count or "diff" and platelet count may need to be ordered specifically if they are not included in the CBC. Parameters for normal laboratory values differ among age groups, genders, and laboratories. The laboratory references provided in this course are meant as a guide and are not intended to replace those of your institution.

The average adult circulates approximately 5 liters of blood, divided into approximately 3 liters plasma and 2 liters formed elements or blood cells. Red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes) are produced in the bone marrow. Red blood cells are much more numerous than white blood cells and platelets.

Objectives:
Upon completion of this course, the health professional should be able to:
• List blood tests performed as part of a CBC.
• Recognize the influence of the patient's hydration status on accurate CBC results.
• State normal adult values for CBC test results.
• Describe two physiologic reasons and two pathological reasons for an increase in red blood cells.
• Describe four reasons for a decrease in red blood cells.
• Identify panic values for hematocrit, hemoglobin, white blood cells, and platelets.
• Recognize the purpose of hemoglobin in red blood cells.
• Describe the calculation relationship between hematocrit and hemoglobin.
• Describe the impact of pregnancy on CBC results.
• Identify the purpose of erythrocyte indices.
• Describe classifications of anemias based on the results of erythrocyte indices.
• List five types of white blood cells and state the function of each type of cell.
• State the implications of a "shift to the left" on a white blood cell differential.
• Identify common patterns of white blood cell increase or decrease in disease processes.
• Recognize the function of platelets in normal coagulation.
• Formulate nursing diagnoses and describe interventions for a patient with an elevated RBC count, a decreased hematocrit, a decreased neutrophil count, and a decreased platelet count.