Chapter 41 Hematology

Hematologic Tests Second most common type of tests performed in POL Cellular components of blood affected by changes in organs or tissues of body Watch the animation

Types of Blood Tests Hemoglobin Hematocrit White blood cell (WBC) count Red blood cell (RBC) count Platelet count Differential WBC count Erythrocyte sedimentation rate (ESR) Prothrombin time

Hematologic Tests Results of tests provide valuable information for diagnosis, evaluating patient’s progress, or regulating further treatment

Complete Blood Count Hemoglobin determination Hematocrit determination WBC count

Complete Blood Count RBC count Differential WBC count Erythrocyte indices

Hemoglobin and Hematocrit Major component of erythrocyte and carrier of oxygen in body; 85 percent of dry weight of RBC Synthesis of heme requires iron Adult male requires 0.5 mg/day of iron Menstruating female requires 2 mg/day of iron

Hemoglobin and Hematocrit Carries 95 percent of oxygen to cells Transports 27 percent of carbon dioxide back to lungs for removal Acts as buffer system

Hemoglobin and Hematocrit Separation of blood into liquid portion and solid portion by process of centrifugation Erythropoietin Hormone that triggers production of new red cells Hemoglobinopathies Group of diseases; abnormal forms of hemoglobin

Hemoglobin and Hematocrit Iron deficiency anemia Near-normal hematocrit with low hemoglobin value; hypochromic RBC lack hemoglobin Determining hemoglobin values Cyanmethemoglobin

Hemoglobin and Hematocrit Normal hemoglobin values or reference ranges by age or sex Normal hematocrit values or reference ranges by age or sex

Hemoglobin and Hematocrit Microhematocrit Centrifuge Packed cell column showing separation of cellular components >>

WBC and RBC Counts WBC and RBC counts WBC differential Automated method WBC differential Normal leukocyte counts

Leukocyte Identification Guide

Leukocyte Differentiation Groups Myelocytic or granulocytic series Lymphocytic Monocytic

Leukocyte Differentiation Granulocytic group Neutrophil Eosinophil Basophil Differential leukocyte count Normal values for a differential leukocyte count in adults

Erythrocyte Indices Include: Mean corpuscular volume (MCV) Mean corpuscular hemoglobin (MCH) Mean corpuscular hemoglobin concentration (MCHC)

Erythrocyte Indices Provide information about size of RBC and hemoglobin content Normal values

Erythrocyte Indices Using erythrocyte indices to diagnose MCH and MCV increased in megaloblastic anemias MCH and MCV decreased in hypochromic and microcytic anemias MCHC increased in hereditary spherocytosis MCHC normal in macrocytosis MCHC decreased in iron deficiency anemia

Erythrocyte Sedimentation Rate Measures rate at which RBC fall toward bottom when placed in vertical tube >>

Erythrocyte Sedimentation Rate Also called “sed rate” Used in diagnosis and treatment of many diseases Inexpensive Accurate Easy to perform

Erythrocyte Sedimentation Rate Wintrobe method EDTA venous blood sample mixed Blood transferred with Pasteur pipette to Wintrobe tube No air bubbles Place tube vertically in rack to stand for 60 minutes Read number of millimeters red cells settled Normal values for Wintrobe method of ESR

Erythrocyte Sedimentation Rate Westergren method Mix blood sample with 3.8 percent sodium citrate solution before filling tube Normal values for Westergren method of ESR Sediplast ESR system

Erythrocyte Sedimentation Rate Guidelines for Wintrobe and Westergren ESR procedures to measure accurate results Rouleaux >>

Erythrocyte Sedimentation Rate Using the ESR to diagnose ESR increased in infections and inflammatory diseases, tissue destruction, and other conditions leading to increased plasma fibrinogen ESR increased with anemia, menstruation, pregnancy, malignant neoplasms, and multiple myeloma ESR normal in osteoarthritis, some cases of cirrhosis, and malaria ESR decreased in polycythemia, spherocytosis, and sickle cell anemia

Coagulation Studies Prothrombin Time (PT) “Protime” Measures time it takes a patient’s blood to clot Normal blood clots in 11-13 seconds International Normalized Ratio (INR) Can be universally applied

Automated Hematology Instrumentation and Quality Control Hematology instruments that require sample dilutions Hematology instruments that do not require sample dilutions

Automated Hematology Instrumentation and Quality Control CLIA ’88 regulation for quality control in automated hematology

Automated Hematology Instrumentation and Quality Control Required procedures Calibration Control samples Proficiency testing Check manufacturer’s recommendations for particular piece of equipment