Complete Blood Count (CBC) PDF

# Complete Blood Count (CBC) ## Objectives 1. To estimate the number of RBC in blood sample 2. To estimate the number of total WBC in blood sample 3. To perform a differential count for a blood sample ## Introduction * Complete blood count (CBC) is a test that gives information about the cells i...

# Complete Blood Count (CBC) ## Objectives 1. To estimate the number of RBC in blood sample 2. To estimate the number of total WBC in blood sample 3. To perform a differential count for a blood sample ## Introduction * Complete blood count (CBC) is a test that gives information about the cells in a patient's blood. * A CBC test usually includes: * WBC count. * Platelet count * WBC differential count. * Mean platelet volume (MPV) * RBC count. * HCT * Hb * Red blood cell indices: There are three red blood cell indices: mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC). ## CBC can applied by two way: 1. Automated blood count 2. Manual blood count ## Automated blood count: * CBC is performed by an automated analyzer that counts the numbers and types of different cells within the blood. * It aspirates a very small amount of the sample through the narrow tubing. Within this tubing, there are sensors that count the number of cells going through it, and can identify the type of cell; this is called **flow-cytometry**. ## Manual blood count * This measurement is made with a microscope and a specially ruled chamber (hemocytometer) using diluted blood. ## (A) Red blood count: * It is test done to determination the number of RBC in a sample of blood, also it evaluate the size and shape of RBC * It is range from 4.2 – 5.5 million RBC per cubic millimeter (mm³) * It is considered a very important indicator of a patent's health ### Low RBC count * Anemia * Acute or chronic blood loss * Malnutrition * Chronic inflammation ### High RBC count * Polycythemia * Congenital heart disease * Renal problem ### Normally high (RBC count) * People who live at high altitudes * Smokers Oxygen is low RBC synthesis increases ### Principle The process involves by counting cells in several squares of the grid and obtain an average number, this number is multiply by a factor that compensates the amount of dilution. The final results expresses the number of RBC /mm³ of original blood sample. ## (B) WBC count : * Total leukocytes count shows the number of WBC in a sample of blood. * A normal WBC count is between 4,500 and 11,000 cells per cubic millimeter. * The number of WBC is sometimes used to identify an infection or to monitor the body's response to treatment. ### Low WBC count ! Leukopenia * A Condition in which the number of leukocytes is abnormally low and which is most commonly due to sever infections (such as HIV) and radiation poisoning. ### High WBC count ! Leukocytosis * A condition characterized by an elevated the number of WBC occur as a result of an infection, or cancer (Leukemia). It can occur normally after eating fat-rich meals. ### Principle * It is necessary to obtain RBC free preparation of WBC from blood. * Suspension of the red blood cell in a very hypotonic solution will lead to the destruction of RBC. ## How to count blood cells * Counting 2 sides in L shape (Le. count the Cells settle on the Top and left sides (colored sides) and exclude the cells on the right and the bottom sides) * Counting is Zigzag in all squares * Blue cells is counted gray cells isnot counted ### Calculations ### RBC blood cell count (5 squares) * Find the sum of RBCs in 5 large squares, and divide it with 80 (5 X 16) small squares to find the average in one square, multiply it by 200 to allow for the dilution and then multiply by 4000 to obtain the number per cubic milliliter. * The sum of RBCs in 5 large squares = 84+71+63+93+83= 394 cells. * The average of RBCs in one square= 394/80 = 4.9 cells. * RBC count= 4.9 x 200 x 4000 = 4 million/mm³. Normal range= 4.2-5 million/mm³ ### WBC blood cell count (4 squares) * Find the sum of WBCs in 4 large squares, and divide it with 64 (4 X 16) small squares to find the average in one square, multiply it by 20 to allow for the dilution and then multiply by 160 to obtain the number per cubic milliliter. * The sum of WBCs in 4 large squares = 16+21+17+15= 69 cells. * The average of WBCs in one square= 69/64 = 1.07 cells. * WBC count= 1 x 20 x 160 = 3200 Cells/mm³. Normal range= 4500-11000 cells /mm³ ## (C) Differential Count * It determines the number of each type of WBC present in the blood | Class of White Cells | White Cell Type | % of total white cell population | |---|---|---| | Granulocytes | Polymorphonuclear Granulocytes | 40 - 75 | | Granulocytes | Bashophiles | Approx. 1 | | Granulocytes | PMN | 1 - 6 | | Granulocytes | Monocytes | 2 -10 | | Non-granular Leucocytes | Lymphocytes | 20 - 45 | | Non-granular Leucocytes | Plasma cells | Õ | Õ: Rarely seen in blood, but present in the tissues. ### Principle * Classification of polymorphonuclear granulocytes (PMN) is based on the size, shape, number and staining characteristics of their granules. ### Leishman's stain * It is based on a mixture of methylene blue and eosin. * It differentiates between WBC as indicated in the following table: | Type of Cell | Colour of the Stain | |---|---| | Neutrophils nuclei | Purple | | Eosinophil granules | Orange - Red | | Basophiles granules | Dark Blue | | Lymphocytes nuclei | Dark Purple | | Platelets granules | Violet | | RBC | Pink |