FBC

• Full Blood Count (FBC) includes:

  • Red cell parameters: haemoglobin (Hb), red cell distribution width (RDW), red cell count (RCC), mean cell volume (MCV), mean cell haemoglobin (MCH), mean cell haemoglobin concentration (MCHC), and haematocrit (Hct)
  • Red cell indices are calculated from measured parameters like MCH, MCHC, HCT, and MCV
• White cell count and differential count (Diff) in FBC:

  • White cell count (WCC) is the number of white cells per volume of blood
  • Differential count reflects the different types of white cells that make up the white cell count
• Differential count is expressed as a percentage and as an absolute count:

  • Percentage gives the relative proportion of different white cell types
  • Absolute count indicates how many cells of each white cell type there are
• Leucocytes (white blood cells) include:

  • Phagocytes: Monocytes, Granulocytes (Neutrophils, Eosinophils, Basophils)
  • Immunocytes: B lymphocytes, T lymphocytes (CD4, CD8), Natural killer cells, Plasma cells
• Functions of leucocytes:

  • Neutrophils and monocytes phagocytose and kill organisms
  • Eosinophils play a role in allergic responses and kill parasites
  • Basophils play a role in immediate hypersensitivity reactions and anti-parasitic functions
  • Lymphocytes are involved in antibody production, cell-mediated immunity, and regulation of the immune response
• Cell counts can indicate quantitative changes in disease states:

  • Cytopenia: decrease in cell numbers (e.g., leukopenia, thrombocytopenia, neutropenia, lymphopenia)
  • Philia: increase in cell numbers (e.g., neutrophilia, basophilia)
  • Cytosis: general increase in cell numbers (e.g., leucocytosis, lymphocytosis, thrombocytosis)
• Possible causes of cell count changes:

  • Basophilia: myeloproliferative disorders, inflammation/infection, hypothyroidism
  • Basopenia: steroid therapy, stress, hyperthyroidism
• The diagnosis of haematological disorders is based on clinical history, patient examination, and laboratory tests like FBC, differential count, peripheral blood smear examination, bone marrow aspiration, trephine biopsy, and specialized tests such as immunophenotyping and cytogenetic analysis
• Peripheral blood investigations use different tubes like purple top/EDTA for FBCs, blue top/Trisodium citrate for plasma tests, and pink top for special blood grouping tubes
• Automated laboratory analysers measure haemoglobin, count and size cells, and perform a differential count in FBC
• The process of phagocytosis involves a cell engulfing a foreign particle, starting with attachment to the cell membrane, formation of a phagocytic cup, closure to form a phagosome, fusion with a lysosome, and expulsion of debris by exocytosis
• A dipstick test is used to determine the presence of certain substances in a urine sample by reacting with chemicals on the dipstick, causing a color change
• A blood smear with red blood cells and a platelet is used to examine blood morphology
• A yeast cell image is relevant for microbiology studies
• A blood smear with a neutrophil image is used to study white blood cells and their role in fighting infection
• An image of the different types of leukocytes (white blood cells) helps in understanding the immune system and infection response
• An illustration of the composition of blood is essential for understanding blood components
• The University of Cape Town logo is not directly related to the medical laboratory science content
• The scientist in a laboratory setting using a microscope is relevant for laboratory work and analysis
• An image of a rack of test tubes labeled with barcodes is used in laboratory settings for sample organization
• An image of a Sysmex XN-3100 Automated Hematology System is used for automated blood analysis
• A complete blood count (CBC) test result image is used to interpret blood test results
• The image of a dipstick test is relevant for understanding urine sample analysis
• The diagram showing the process of phagocytosis is important for understanding cellular processes in the immune system
• The image of a blood smear with red blood cells and a platelet is used for studying blood morphology
• The image of a yeast cell is relevant for microbiology studies
• The image of a blood smear with a neutrophil is used to study white blood cells and their role in fighting infection
• A complete blood count (CBC) test measures the number of red blood cells, white blood cells, platelets, hemoglobin, and hematocrit in the blood

  
• A dipstick test is used to determine the presence of certain substances in a urine sample by reacting with chemicals on the strip

  
• There are five main types of leukocytes: neutrophils, monocytes, eosinophils, basophils, and lymphocytes, each with a specific role in the immune response

  
• Phagocytosis is a process where a cell engulfs a foreign particle, starting with attachment, formation of a phagocytic cup, closing to form a phagosome, fusion with a lysosome, and expulsion of debris by exocytosis

  
• Pancytopenia includes anemia, neutropenia, and thrombocytopenia, but a leukopenia with preserved neutrophil count, anemia, and thrombocytopenia does not constitute pancytopenia
• Some causes of pancytopenia include defects in stem cells, aplastic anemia, congenital bone marrow failure syndromes, and certain malignancies
• Causes for a decrease/increase in platelets include thrombocytopenia, thrombocytosis, decreased production, increased consumption, and pseudothrombocytopenia
• Normal neutrophils have a segmented nucleus with 3-5 lobes, pink cytoplasm with fine purple granules, and are the most common type of white blood cell
• Morphological changes in neutrophils can include toxic granulation, vacuolation, and phagocytosis
• Reactive lymphocytes can show large granules, while normal lymphocytes have a more uniform appearance
• Initial laboratory tests for patient workup include full blood count (FBC), differential count, smear review, and reticulocyte count
• Normal adult reference ranges include hemoglobin, white cell count, and platelet count
• Some clonal hematological diseases involving white cells are acute leukemias, myeloproliferative diseases, myelodysplastic syndromes, lymphomas, and plasma cell dyscrasias