Hematology Quiz: Complete Blood Count

Hematology Overview

• Hematology is the study of blood and blood disorders.
• This week's focus is on blood tests, indices, and related conditions.
• Blood components include cells, platelets, and plasma.

Instructional Objectives

• Understand complete blood counts (CBC), including RBC indices (MCV, MCH, MCHC, RDW), hemoglobin, hematocrit, and platelets.
• Identify common causes of anemia and polycythemia.
• Analyze the reticulocyte count and its significance.
• Differentiate between ferritin, iron, total iron binding capacity (TIBC), and transferrin, and their diagnostic applications.
• Understand the relationship between vitamin B12, folate, and megaloblastic anemia.
• Understand the functions and abnormalities of different types of white blood cells (neutrophils, lymphocytes, monocytes, eosinophils, basophils, thrombocytes).
• Recognize white blood cell inclusions and their associated conditions.
• Distinguish between Hodgkin's and non-Hodgkin's lymphoma.
• Differentiate between various types of leukemia (CLL, ALL, CML, AML) based on lab findings.
• This content is centered around understanding the different components of a CBC, their roles in diagnosing pathologies, and their relationships to various health conditions.

Blood Components

• Plasma (liquid portion)
• Red blood cells (RBCs or erythrocytes)
• White blood cells (WBCs or leukocytes)
• Platelets (thrombocytes)

Complete Blood Count (CBC)

• A series of tests providing information about RBCs, platelets, and WBCs.
• Easy, quick, and inexpensive.
• Includes RBC count, hemoglobin, hematocrit, platelets, RBC indices (MCV, MCH, MCHC, RDW), and WBC count and differential.
• WBC differential identifies five white blood cell types (neutrophils, lymphocytes, monocytes, eosinophils, and basophils).

Erythrocyte Count (RBCs)

• Measures the number of RBCs in a blood sample.
• Reference range: male: 4.7-6.1; female: 4.2-5.4 (x10¹²/L).
• Lower values in females due to menstruation.
• Declining count with age.
• Decreased count indicates anemia (reduced RBC production or loss).
• Increased count indicates polycythemia (potentially physiological due to high altitudes or dehydration).

Anemias

• Macrocytic Anemia (larger RBCs): Often due to vitamin B12 or folate deficiency.
• Microcytic Anemia (smaller RBCs): Commonly caused by iron deficiency.
• Pancytopenia: Deficiency of all blood cell types (RBCs, WBCs, platelets).

Reticulocytes

• Immature RBCs released from bone marrow.
• Increased levels indicate the bone marrow is attempting to compensate for RBC loss.
• Low levels in the presence of anemia may indicate inadequate bone marrow response.

Hemoglobin (Hgb)

• Protein in RBCs transporting oxygen.
• Reference range: male: 14-18; female: 12-16 g/dL.
• Low levels indicate anemia.

Hematocrit (Hct)

• Percentage of blood volume occupied by RBCs.
• Reference range: male: 42-52%; female: 37-47%.
• Closely related to but not identical to hemoglobin levels.
• Elevated or decreased values correlate with similar pathologies to RBC (red blood cell) count.

Platelet Count (Plt)

• Number of thrombocytes essential for blood clotting.
• Reference range: 150,000-400,000/mm³.
• Low levels (thrombocytopenia) often due to reduced production, increased destruction, or sequestration.
• High levels (thrombocytosis) can be a result of various conditions or cancers.

Mean Platelet Volume (MPV)

• Reflects the average size of platelets.
• Increased MPV suggests presence of immature platelets (reticulated platelets), commonly seen in conditions like leukemia.
• Decreased MPV suggests underproduction of platelets.

Red Blood Cell Indices

• Provide information about RBC size, hemoglobin content, and concentration.
• Includes MCV, MCH, MCHC, and RDW.

White Blood Cell Count (WBC)

• Measures the number of leukocytes in a blood sample
• Reference range: 5,000-10,000/mm³.
• Increased count (leukocytosis) indicates infection.
• Decreased count (leukopenia) usually associated with bone marrow disease or overwhelming infections.

White Blood Cell Differential

• Identifies the percentage of each type of leukocyte (WBC).
• Includes neutrophil, lymphocyte, monocyte, eosinophil, and basophil proportions.
• Alterations in percentages indicate specific systemic conditions.

WBC Inclusions

• Specific cellular structures or inclusions present during certain conditions or pathologies. Examples include: -Hypersegmented neutrophils: Suggestive of vitamin deficiencies (B12 and folate). -Dohle bodies: Associated with stress or infectious conditions. -Auer rods: Indicative of acute myeloid leukemia.

Leukemia

• Cancer of the blood-forming cells.
• Divided into acute and chronic forms, with different presentations and underlying mechanisms.
• Diagnose and identify these conditions with a blood smear and bone marrow biopsy.

Lymphomas

• Cancers arising from lymphocytes.
• Two main types are Hodgkin's and non-Hodgkin's lymphomas.
• Diagnose with a biopsy and identifying reed-Sternberg cells for Hodgkin's diagnosis.

Iron Panel

• Measures serum iron, TIBC/transferrin, transferrin saturation, and ferritin to assess iron metabolism and storage.
• High TIBC usually indicates iron deficiency.
• Used to diagnose iron-related conditions or other issues.

Erythrocyte Sedimentation Rate (ESR)

• Measures how quickly RBCs settle.
• Elevated ESR often indicates inflammation/infection.
• Also used to monitor treatment for inflammatory disease.

C-reactive Protein (CRP)

• Acute-phase reactant protein produced in response to inflammation or infection.
• Used to detect/track inflammation, monitor disease/infection activity, and used for cardiac risk scoring. Increased amounts correlate with various factors.

Coagulation Panel

• Set of tests evaluating blood clotting.
• Includes bleeding time, protime/prothrombin time (PT), partial thromboplastin time (PTT), INR, and fibrinogen.
• Used to detect clotting disorders and abnormalities in the various clotting mechanisms.

D-dimer

• Protein fragment created by the breakdown of blood clots.
• Elevated levels suspected in thrombotic disorders (such as DVT/PE).
• Also important in screening patients for thrombotic conditions.