Unit 1: Introduction to haematology
Basic Haematology & Haematological Techniques-I notes · PTU syllabus (BMLS301-18)
On this page
Unit summary
Haematology is the study of blood and blood-forming tissues. This unit covers the definition and importance of haematology, laboratory equipment, organisation and safety, the composition and functions of blood, and the formation of blood cells — erythropoiesis, leucopoiesis and thrombopoiesis.
After this unit you can
- Explain the scope of haematology and its equipment
- Organise a safe haematology laboratory
- Describe the composition and normal cellular components of blood
- Describe erythropoiesis, leucopoiesis and thrombopoiesis
PTU syllabus topics
- Definition
- importance and equipment used in haematology
- laboratory organization and safety measures
- composition and function of blood and normal cellular components
- formation of cellular components — erythropoiesis
- leucopoiesis
- thrombopoiesis
Erythropoiesis
Red blood cells
Leucopoiesis
White blood cells
Thrombopoiesis
Platelets from megakaryocytes
Topic 1
Definition and importance of haematology
- Haematology: the branch of medicine and laboratory science dealing with blood, blood-forming organs and blood diseases — anaemias, leukaemias, bleeding and clotting disorders.
- Importance: the complete blood count is among the most requested tests; it screens for infection, anaemia, leukaemia and monitors chemotherapy and many treatments.
Topic 2
Equipment used in haematology
Automated haematology analyser
CBC: Hb, RBC, WBC, platelets, indices, 3- or 5-part differential
Impedance (Coulter principle) and flow cytometry
Microscope
Blood films, manual counts
Oil immersion for differential counts
Neubauer counting chamber (haemocytometer)
Manual cell counts
Improved Neubauer ruling, depth 0.1 mm
Sahli's haemoglobinometer
Visual Hb estimation
Largely replaced by photometric methods
Colorimeter or spectrophotometer
Cyanmethaemoglobin Hb method
540 nm
Microhaematocrit centrifuge
Packed cell volume
10,000–12,000 rpm
ESR stands
Westergren and Wintrobe tubes
Vertical, vibration-free
Coagulometer
PT, APTT
Semi- or fully automated
Topic 3
Laboratory organisation and safety
- Sections
- Sample reception, routine haematology, coagulation, special tests (bone marrow, flow cytometry)
- Workflow
- Request → collection → accession → testing → verification → report
- Quality
- Internal QC (commercial controls), external quality assessment, equipment calibration
- Records
- Registers, QC charts, maintenance logs
- Safety: treat all blood as infectious (universal precautions); gloves, coats, eye protection; no mouth pipetting; sharps containers; disinfect spills with 1% hypochlorite; hepatitis B vaccination.
Topic 4
Composition and normal cellular components of blood
Haemoglobin
13–17 g/dL
12–15 g/dL
Red cell count
4.5–5.5 million/µL
3.8–4.8 million/µL
Packed cell volume
40–50%
36–46%
Total leucocyte count
4,000–10,000/µL
4,000–10,000/µL
Platelets
1.5–4.1 lakh/µL
1.5–4.1 lakh/µL
Neutrophils
40–80%
Phagocytosis of bacteria
Lymphocytes
20–40%
Immunity (B and T cells)
Monocytes
2–10%
Become macrophages
Eosinophils
1–6%
Allergy, parasites
Basophils
Less than 2%
Histamine release
Topic 5
Erythropoiesis
- Haemopoiesis occurs in the yolk sac, then liver and spleen (fetus), then red bone marrow (after birth; in adults mainly flat bones and ends of long bones). All cells come from the pluripotent haemopoietic stem cell.
- 1
Pronormoblast
- 2
Early (basophilic) normoblast
- 3
Intermediate (polychromatic) normoblast — haemoglobin appears
- 4
Late (orthochromatic) normoblast — nucleus condenses and is expelled
- 5
Reticulocyte — RNA remnants; 1–2 days in blood
- 6
Mature erythrocyte — lives about 120 days
- Regulation: erythropoietin from the kidney in response to hypoxia. Requirements: iron, vitamin B12, folic acid, protein, vitamin C, copper; takes about 7 days.
Topic 6
Leucopoiesis
- 1
Myeloblast
- 2
Promyelocyte (primary granules)
- 3
Myelocyte (specific granules — neutrophil, eosinophil or basophil)
- 4
Metamyelocyte (kidney-shaped nucleus)
- 5
Band form
- 6
Segmented granulocyte
- Monopoiesis: monoblast → promonocyte → monocyte. Lymphopoiesis: lymphoblast → prolymphocyte → lymphocyte; T cells mature in the thymus. Regulated by colony-stimulating factors (G-CSF, GM-CSF) and interleukins.
Topic 7
Thrombopoiesis
- Megakaryoblast → promegakaryocyte → megakaryocyte: the large polyploid megakaryocyte sheds cytoplasmic fragments as platelets (each produces thousands). Regulated by thrombopoietin from the liver. Platelets live 7–10 days; about a third are held in the spleen.
Key terms
- Haemopoiesis
- Formation of blood cells
- Erythropoietin
- Kidney hormone stimulating red cell production
- Reticulocyte
- Immature red cell with residual RNA
- Megakaryocyte
- Large marrow cell producing platelets
- Haemocytometer
- Counting chamber for manual cell counts
Quick revision
- Haematology scope; analysers, haemocytometer, colorimeter, centrifuge, ESR stands.
- Organisation, QC, safety.
- Normal Hb, RBC, PCV, WBC, platelet values; differential count ranges.
- Sites of haemopoiesis; stem cell; erythropoiesis stages and needs.
- Granulopoiesis, monopoiesis, lymphopoiesis; thrombopoiesis.
Important exam questions
Practice questions written to the PTU exam pattern for this unit's syllabus: short answers (Section A style) and long answers (Sections B and C style).
Short-answer questions
- Q1.Define haematology.
- Q2.Give normal Hb values for men and women.
- Q3.Name the hormone regulating erythropoiesis.
- Q4.List the stages of erythropoiesis.
- Q5.What is a band form?
- Q6.How long do platelets survive?
Long-answer questions
- Q1.Describe the equipment and organisation of a haematology laboratory.
- Q2.Describe the composition of blood and normal values.
- Q3.Describe erythropoiesis and its regulation.
- Q4.Describe leucopoiesis and thrombopoiesis.
Stuck on this unit?
Message SBS on WhatsApp for help with Basic Haematology & Haematological Techniques-I, or to ask about studying B.Sc MLS at Synetic.