Hematology Notes

MAC Academy HEMATOLOGY ❖ Lecture 1 Introduction to Hematology Objectives By the end of this lecture, the student should be able to: ✓ Define Hematology. ✓ Identify the functions of blood. ✓ Describe the composition of blood. ✓ Explain hematopoiesis. ✓ Recognize the sites of blood cell production. ✓ Understand the role of hematopoietic growth factors. ❖ What is Hematology? • Hematology is the branch of laboratory medicine that studies: ✓ Blood ✓ Blood-forming organs ✓ Blood diseases ✓ Hemostasis and coagulation ✓ It includes the diagnosis, monitoring, and management of disorders affecting blood cells and coagulation ❖ What is Blood? • • Blood is a specialized connective tissue composed of cells suspended in a liquid matrix called plasma. It circulates throughout the body to maintain homeostasis ✓ Average blood volume: Male: 5–6 L Female: 4–5 L ✓ Blood represents approximately 7–8% of body weight. ❖ Functions of Blood 1. Transportation Blood transports: Oxygen (O₂) Carbon dioxide (CO₂) Nutrients Hormones Metabolic waste products Drugs 1 MAC Academy 2. Regulation Blood helps regulate: Body temperature pH Fluid balance Electrolytes 3. Protection Blood protects the body through: White blood cells Antibodies Blood clotting mechanism ❖ Composition of Blood ✓ Blood consists of two major components: • Plasma (55%) Liquid portion of blood. o Contains: Water (90–92%) Proteins Electrolytes Glucose Hormones Lipids Enzymes Waste products • Formed Elements These include: (45%) ✓ Red Blood Cells (RBCs) Function: Transport oxygen and carbon dioxide. ✓ White Blood Cells (WBCs) Function: Body defense against infection. ✓ Platelets Function: Blood clotting and prevention of bleeding ❖ Blood Cell Percentages Approximate percentages: Plasma → 55% RBCs → 44–45% Buffy coat (WBCs + Platelets) → 1 ‫أقل من‬% 2 MAC Academy 3 MAC Academy Hematopoiesis ❖ Definition: • • Hematopoiesis is the process of production, maturation, and differentiation of all blood cells from hematopoietic stem cells. Occurs continuously throughout life ❖ Hematopoietic Stem Cell (HSC) ✓ Characteristics: Multipotent Self-renewal Can differentiate into all blood cells All blood cells originate from one stem cell. Differentiation of Blood Cells 4 MAC Academy ❖ Sites of Hematopoiesis ✓ During fetal life Yolk sac Liver Spleen Bone marrow ✓ After birth Main site: Bone Marrow Especially in: Sternum Vertebrae Pelvis Ribs Skull Proximal femur Proximal humerus ❖ Hematopoietic Growth Factors These hormones regulate blood cell production. A. Erythropoietin (EPO) Source: Kidney (90%) Liver (10%) Function: Stimulates RBC production in response to hypoxia. B. Thrombopoietin (TPO) Source: Liver (main source) Kidney Function: Stimulates megakaryocyte maturation and platelet production. C. G-CSF Granulocyte Colony Stimulating Factor Function: Stimulates neutrophil production. 5 MAC Academy D. GM-CSF Granulocyte-Macrophage Colony Stimulating Factor Function: Stimulates granulocytes and monocytes. E. Interleukins Examples: IL-3 IL-5 IL-7 Function: Support growth and differentiation of blood cells. ❖ Blood Cell Life Span ✓ ✓ ✓ ✓ ✓ RBC:- 120 days Platelet:- 7–10 days Neutrophil:- 6–8 hours in blood Monocyte:- 1–3 days Lymphocyte :- Weeks to years ❖ Clinical Importance Abnormalities in hematopoiesis may lead to: Anemia Leukemia Polycythemia Leukopenia Thrombocytopenia Thrombocytosis 6 MAC Academy CBC REPORT 7 MAC Academy ❖ Lecture 2 Complete Blood Count (CBC) • Objectives ✓ By the end of this lecture, the student should be able to: Define CBC. Identify CBC parameters. Understand RBC indices. Interpret CBC systematically. Recognize abnormal CBC findings. ❖ What is CBC? • Complete Blood Count (CBC) is the most commonly requested hematology test. It provides quantitative information about: Red blood cells White blood cells Platelets It is used as a screening, diagnostic, and monitoring test. • Sample Specimen: Whole Blood Anticoagulant: EDTA (Lavender Tube) • CBC Components CBC consists of three major parts: ✓ RBC Parameters RBC count Hemoglobin (Hb) Hematocrit (HCT) MCV MCH MCHC RDW ✓ WBC Parameters Total WBC Count Differential Count ✓ Platelet Parameters MPV PDW PCT 8 MAC Academy ❖ Hemoglobin (Hb) • Definition: ✓ ✓ ✓ The protein inside RBCs responsible for oxygen transport. Normal values: Male: 13–17 g/dL Female: 12–15 g/Dl Clinical significance: ↓ Hb → Anemia ↑ Hb → Polycythemia, dehydration ❖ RBC Count ✓ ✓ Measures the number of red blood cells. Clinical significance: ↓ RBC → Anemia ↑ RBC → Polycythemia ❖ Hematocrit Definition: • • • (HCT) Percentage of blood occupied by RBCs. Low: Anemia High: Dehydration Polycythemia ❖ RBC Indices • RBC indices help classify anemia. They include: MCV MCH MCHC RDW ▪ MCV " Mean Corpuscular Volume" ✓ Measures: Average size of RBC. Normal: 80–100 fL Interpretation: <80 → Microcytic 80–100 → Normocytic 100 → Macrocytic 9 MAC Academy ▪ MCH " Mean Corpuscular Hemoglobin" ✓ Measures: Amount of hemoglobin in one RBC. Normal: 27–33 pg Low: Hypochromic cells. ▪ MCHC " Mean Corpuscular Hemoglobin Concentration" ✓ Measures: Concentration of hemoglobin inside RBC. Normal: 32–36 g/dL Low: Iron deficiency High: Hereditary spherocytosis (rare) ▪ RDW " Red Cell Distribution Width" ✓ Measures: Variation in RBC size. Normal: 11.5–14.5% High RDW means anisocytosis. ❖ WBC Count ✓ Normal: 4–11 ×10⁹/L Increase: Infection Inflammation Leukemia Decrease: Viral infection Bone marrow suppression ❖ Platelets Normal: 150–450 ×10⁹/L Low: Bleeding tendency High: Risk of thrombosis 10 MAC Academy How to Interpret CBC ✓ Step 1 Look at Hb. Low? → Patient has anemia. ✓ Step 2 Look at MCV. Low → Microcytic Normal → Normocytic High → Macrocytic ✓ Step 3 Look at MCH & MCHC. Low? → Hypochromic anemia. ✓ Step 4 Look at RDW. High RDW → Different RBC sizes. Suggests Iron deficiency or mixed anemia. Normal RDW→ More likely Thalassemia trait or chronic disease. ✓ Step 5 Evaluate WBC. High? Infection? Leukemia? Low? Viral infection? Drug effect? ✓ Step 6 Evaluate Platelets. Low? Bleeding risk. High? Thrombosis risk. 11 MAC Academy Lecture 3 Anemia Learning Objectives ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ By the end of this lecture, the student should be able to: Define anemia. Understand the physiological importance of hemoglobin. Recognize the causes and symptoms of anemia. Classify anemia according to different methods. Classify anemia based on Mean Corpuscular Volume (MCV). Correlate laboratory findings with clinical diagnosis. Understand the first step in anemia interpretation using CBC ✓ Introduction o Anemia is one of the most common hematological disorders encountered in clinical practice. It affects millions of people worldwide and may occur at any age. o Anemia is not a disease by itself, but rather a laboratory finding or manifestation of an underlying disorder. Therefore, whenever anemia is detected, the clinician or laboratory specialist should always search for the underlying cause. o The primary function of red blood cells (RBCs) is to transport oxygen from the lungs to body tissues through hemoglobin. Therefore, any decrease in hemoglobin concentration reduces oxygen delivery to tissues, leading to the characteristic clinical manifestations of anemia. ✓ Definition of Anemia • • • • • Anemia is defined as a decrease in the oxygen-carrying capacity of blood due to a reduction in one or more of the following: Hemoglobin concentration (Hb) Hematocrit (HCT) Red Blood Cell count (RBCs) Among these parameters, Hemoglobin (Hb) is considered the most important laboratory parameter for diagnosing anemia. 12 MAC Academy  Important Note A patient may have a normal RBC count but still be anemic if the hemoglobin concentration is low. Therefore, anemia is diagnosed primarily according to Hb concentration, not the RBC count. ❖       Normal Function of Hemoglobin Hemoglobin is an iron-containing protein found inside red blood cells. Its main functions are: Transport oxygen from the lungs to body tissues. Transport part of carbon dioxide from tissues back to the lungs. Help maintain acid-base balance. When hemoglobin decreases, tissues receive less oxygen, resulting in tissue hypoxia. ▪ Why Do Patients Develop Symptoms?  The symptoms of anemia are mainly caused by:  Reduced oxygen delivery (Tissue Hypoxia).  When tissues receive insufficient oxygen, the body attempts to compensate by increasing cardiac output and respiratory rate.  Consequently, patients develop fatigue, weakness, palpitations, and shortness of breath. ❖ Clinical Manifestations of Anemia ✓ General Symptoms o o o o o o ✓ Fatigue Generalized weakness Easy fatigability Dizziness Headache Reduced exercise tolerance Cardiovascular Symptoms o o o o o o o o Palpitations Tachycardia Chest pain (in severe anemia) Heart failure in advanced cases Respiratory Symptoms Shortness of breath Dyspnea on exertion Tachypnea 13 MAC Academy ✓ Physical Signs o Pallor of the skin Pale conjunctiva Pale nail beds Cold extremities ✓ Severe Cases o Patients with severe anemia may present with: Syncope Hypotension Angina Congestive heart failure ❖ Causes of Anemia All causes of anemia can be explained by three basic mechanisms. • Blood Loss ✓ The body loses red blood cells faster than it can replace them. Acute Blood Loss Examples: Trauma Surgery Gastrointestinal bleeding Obstetric hemorrhage ✓ Chronic Blood Loss Examples: Heavy menstrual bleeding Peptic ulcer Colon cancer Hemorrhoids Hookworm infection • Decreased RBC Production ✓ The bone marrow fails to produce sufficient red blood cells. Common causes include: o o o o o o o Iron deficiency Vitamin B12 deficiency Folate deficiency Bone marrow failure Chronic kidney disease (decreased Erythropoietin) Chronic inflammatory diseases Malnutrition 14 MAC Academy Increased RBC Destruction (Hemolysis) • ✓ Red blood cells are destroyed before completing their normal lifespan (120 days). Examples include: o o o o o o ❖ Autoimmune hemolytic anemia G6PD deficiency Sickle cell disease Thalassemia Malaria Mechanical heart valves Classification of Anemia According to MCV ✓ Mean Corpuscular Volume (MCV) measures the average size of red blood cells. ✓ Based on MCV, anemia is classified into three major groups: A. Microcytic Anemia MCV <80 fL Red blood cells are smaller than normal. Common causes: Iron deficiency anemia Thalassemia Sideroblastic anemia Anemia of Chronic Disease B. Normocytic AnemiaMCV 80–100 f L Red blood cells have a normal size, but their number or hemoglobin is reduced. Common causes: Acute blood loss Hemolytic anemia Chronic kidney disease Aplastic anemia Anemia of chronic disease C. Macrocytic Anemia MCV >100 fL Red blood cells are larger than normal. Common causes: Vitamin B12 deficiency Folate deficiency Liver disease Alcoholism Hypothyroidism 15 MAC Academy DNA synthesis‫ يحدث بسبب‬Macrocytosis ‫ أما‬Hemoglobin synthesis ‫ يحدث بسبب‬Microcytosis Important Clinical Note The first laboratory step after confirming that Hb is low is to look at the MCV. MCV is considered the starting point for classifying anemia and determining the next investigations. ❖ Mean Corpuscular Hemoglobin (MCH) Definition o MCH measures the average amount of hemoglobin present in one red blood cell. Unit: pg (Picogram) Normal Range27–33 pg o Interpretation Low MCH Each RBC contains less hemoglobin. The cells appear pale. This is called: Hypochromia Seen in: Iron Deficiency Anemia & Thalassemia High MCH Usually occurs when RBCs are large (Macrocytic anemia). Examples: Vitamin B12 deficiency Folate deficiency Clinical Importance MCH reflects the amount of hemoglobin inside each RBC. ❖ Mean Corpuscular Hemoglobin Concentration (MCHC) Definition MCHC measures the average concentration of hemoglobin inside the red blood cell. Unit: g/dL Normal Range32–36 g/dL o Interpretation Low MCHC The RBC contains a lower concentration of hemoglobin. This condition is called: Hypochromic anemia Common causes: Iron deficiency anemia & Thalassemia High MCHC Less common. 16 MAC Academy Clinical Importance MCHC tells you how concentrated hemoglobin is inside the RBC. Easy Tip MCH = Amount MCHC = Concentration ❖ Red Cell Distribution Width (RDW) Definition RDW measures the variation in the size of red blood cells It answers one important question: Are all RBCs nearly the same size, or do they vary significantly? Normal Range 11.5–14.5% o Interpretation Normal RDW Most RBCs have nearly the same size. High RDW There is marked variation in RBC size This condition is called: Anisocytosis ✓ Causes of High RDW Iron Deficiency Anemia Vitamin B12 deficiency Folate deficiency Mixed anemia After blood transfusion • Why is RDW Important? MCV tells you the average size only RDW tells you whether all RBCs are the same size or not. Two patients may have the same MCV, but different RDW values. This helps differentiate diseases. Example Iron Deficiency Anemia MCV ↓ RDW ↑ Because newly produced RBCs are much smaller than older RBCs. -------------------------------------------------------------Thalassemia Trait MCV ↓ RDW Normal Because almost all RBCs are uniformly small -----------------------------------------------------17 MAC Academy Remember This Rule MCV → Size MCH → Amount of Hemoglobin MCHC → Concentration of Hemoglobin RDW → Variation in Cell Size Important Laboratory Notes MCV is used first to classify anemia. MCH and MCHC determine whether the anemia is hypochromic or normochromic. RDW helps differentiate between common causes of anemia, especially Iron Deficiency Anemia and Thalassemia Trait.  Practical Example A CBC report shows: Hb = 8.5 g/dL MCV = 68 fL MCH = 20 pg MCHC = 29 g/dL RDW = 18% ✓ Interpretation Hb ↓ → Anemia MCV ↓ → Microcytic MCH ↓ → Hypochromic MCHC ↓ → Hypochromic RDW ↑ → Marked variation in RBC size Most likely diagnosis: Iron Deficiency Anemia  Case 2 Hb = 10 g/dL MCV = 70 fL MCH = 22 pg RDW = 13% ✓ Interpretation Microcytic anemia with normal RDW. Most likely diagnosis: Thalassemia Trait  Case 3 18 MAC Academy Hb = 9 g/dL MCV = 112 fL RDW = 17% ✓ Interpretation Macrocytic anemia. Most likely diagnosis: Vitamin B12 or Folate Deficiency  Case 4 Hb = 9.5 g/dL MCV = 88 fL Reticulocyte Count = High ✓ Interpretation Normocytic anemia with increased reticulocyte count. Most likely diagnosis: Hemolytic Anemia or Acute Blood Loss  Case 5 Hb = 8.8 g/dL MCV = 90 fL Reticulocyte Count = Low ✓ Interpretation Normocytic anemia with decreased reticulocyte count. Most likely diagnosis: Bone marrow failure, Chronic Kidney Disease, or Anemia of Chronic Disease Key Points to Remember Hb confirms the presence of anemia. MCV classifies anemia into Microcytic, Normocytic, or Macrocytic. MCH and MCHC assess the hemoglobin content of RBCs. RDW evaluates variation in RBC size and helps in differential diagnosis. CBC is the first step, but additional laboratory tests are required to confirm the underlying cause. 19 MAC Academy ❖ Request Confirmatory Tests CBC suggests the diagnosis. Additional laboratory tests confirm the cause. 1. If Microcytic Anemia Order: Serum Iron Serum Ferritin TIBC Transferrin Saturation If iron studies are normal but thalassemia is suspected: Hb Electrophoresis 2. If Normocytic Anemia Order: Reticulocyte Count Kidney Function Tests LDH Indirect Bilirubin Haptoglobin Direct Coombs Test (when autoimmune hemolysis is suspected) 3. If Macrocytic Anemia Order: Vitamin B12 Serum Folate Liver Function Tests Thyroid Function Tests (if clinically indicated) 20 MAC Academy Lecture 4 ESR & Prothrombin Time (PT) Learning Objectives By the end of this lecture, students should be able to: • Define ESR and PT. • Understand the principle of each test. • Know the specimen requirements. • Describe the testing procedure. • Interpret normal and abnormal results. • Identify clinical applications. • Recognize factors affecting each test. • Understand the limitations of ESR and PT. Introduction Although both ESR and PT are common laboratory tests, they measure completely different processes. • ESR is an inflammatory marker. • PT evaluates the extrinsic and common pathways of blood coagulation. Understanding the difference between these tests is essential for proper laboratory interpretation. Part I: Erythrocyte Sedimentation Rate (ESR) Definition The Erythrocyte Sedimentation Rate (ESR) is the rate at which red blood cells settle at the bottom of a vertical tube containing anticoagulated blood over one hour. Unit: mm/hour Principle Normally, red blood cells carry a negative surface charge (zeta potential), causing them to repel each other. During inflammation, plasma proteins such as fibrinogen and immunoglobulins increase, reducing the zeta potential and allowing RBCs to form stacks called Rouleaux Formation. These aggregates are heavier and settle faster, resulting in an increased ESR. Specimen Whole blood. Anticoagulant • Sodium Citrate (Westergren method) • EDTA (can be used with modified methods) Methods Westergren Method (Gold Standard) • Most commonly used. • Measures ESR after 1 hour. Wintrobe Method • Uses a shorter tube. • Less sensitive than Westergren. 21 MAC Academy Normal Values Adult Male: 0–15 mm/hour Adult Female: 0–20 mm/hour Children: 0–10 mm/hour Normal values may vary slightly between laboratories. Causes of Increased ESR • Acute and chronic infections. • Autoimmune diseases (e.g., Rheumatoid Arthritis, Lupus). • Tuberculosis. • Malignancies. • Pregnancy. • Chronic kidney disease. • Anemia (especially normocytic and macrocytic). Causes of Decreased ESR • Polycythemia. • Sickle Cell Disease. • Severe leukocytosis. • Hereditary spherocytosis. • Congestive heart failure. Clinical Uses • Detect inflammation. • Monitor chronic inflammatory diseases. • Follow response to treatment. • Monitor temporal arteritis and polymyalgia rheumatica. Limitations ESR is non-specific. An elevated ESR does not identify the exact disease. Always interpret ESR with: • Clinical findings. • CBC. • CRP. • Other laboratory investigations. 22 MAC Academy Part II: Prothrombin Time (PT) Definition PT measures the time required for plasma to clot after adding tissue factor (thromboplastin) and calcium. Unit: Seconds Principle The test evaluates the Extrinsic Pathway and Common Pathway of coagulation. After adding thromboplastin and calcium to citrated plasma, the clotting time is measured. Specimen Platelet Poor Plasma (PPP). Collection Tube Light Blue Tube Contains: 3.2% Sodium Citrate Important: Blood-to-anticoagulant ratio must be 9:1. Coagulation Factors Evaluated Extrinsic Pathway Factor VII Common Pathway • Factor X • Factor V • Factor II (Prothrombin) • Factor I (Fibrinogen) Normal PT Approximately: 11–13.5 seconds (May vary depending on reagent and laboratory.) International Normalized Ratio (INR) PT results may differ between laboratories because of reagent sensitivity. Therefore, INR is used to standardize PT results. Formula INR = (Patient PT / Mean Normal PT)^ISI Normal INR 0.8–1.2 Therapeutic INR Warfarin therapy: 2.0–3.0 Mechanical heart valve: 2.5–3.5 23 MAC Academy Causes of Prolonged PT • Liver disease. • Vitamin K deficiency. • Warfarin therapy. • Disseminated Intravascular Coagulation (DIC). • Factor VII deficiency. • Severe fibrinogen deficiency. Clinical Uses • Monitoring Warfarin therapy. • Assessing liver synthetic function. • Detecting vitamin K deficiency. • Pre-operative coagulation screening. • Investigating bleeding disorders. 24