64d ago

Haematology Lecture Notes

Haematology

  • Haematology is the study of blood, including:

    • Haemopoiesis

    • Formed elements of blood

    • Haemoglobin

    • Coagulation

    • Blood transfusion / cross matching

  • Blood and bone marrow are intensively studied in haematology.

  • The average adult has approximately 5 litres of blood.

  • Blood is found in:

    • Circulatory system

    • Sinusoids

  • Blood supports the function of body tissues.

  • Blood is a tissue composed of:

    • Formed elements:

      • White blood cells (leucocytes)

      • Red blood cells (erythrocytes)

      • Platelets (thrombocytes)

    • Liquid component: Plasma

Haemopoiesis

  • The production of the formed elements of blood (WBCs, RBCs, and platelets).

    • Erythropoiesis: Production of RBCs.

    • Thrombopoiesis: Production of platelets.

    • Granulopoiesis: Production of granulocytes.

    • Lymphopoiesis: Production of lymphocytes.

    • Monocytopoiesis: Production of monocytes.

  • All cell lines are derived from a single precursor cell.

  • A stem cell differentiates into mature cells under the influence of growth factors.

  • Sites of Haemopoiesis:

    • Foetus: Yolk sac, liver, spleen, bone marrow, lymph nodes.

    • Adult: Bone marrow.

Simplified Cell Lineages

  • Multipotential hematopoietic stem cell (Hemocytoblast) differentiates into:

    • Common myeloid progenitor:

      • Erythrocyte

      • Mast cell

      • Myeloblast:

        • Basophil

        • Neutrophil

        • Eosinophil

        • Monocyte → Macrophage

      • Megakaryocyte → Thrombocytes

    • Common lymphoid progenitor:

      • Small lymphocyte:

        • T lymphocyte

        • B lymphocyte → Plasma cell

      • Natural killer cell (Large granular lymphocyte)

Formed Elements of Blood

  • Red Blood Cell (RBC):

    • Most numerous type of cell in blood.

    • Anuclear.

    • Biconcave disc shape, with an "Area of central pallor".

    • Diameter: 7.2 - 8.0 µm.

    • Lifespan: 120 +/- 20 days.

    • Contains haemoglobin, which transports oxygen and gives RBCs a red colour.

    • Shape allows rapid diffusion of gases and flexibility.

    • Shape maintenance depends on energy and membrane structure (lipid protein carbohydrate).

  • Platelets:

    • Second most numerous type of cell in blood.

    • Discoid shape.

    • Anuclear.

    • Diameter: 3 µm.

    • Small cytoplasmic fragments derived from megakaryocytes.

    • Primary role is the prevention of blood loss.

  • White Blood Cells:

    • Granulocytes (with cytoplasmic granules):

      • Neutrophils

      • Eosinophils

      • Basophils

    • Agranulocytes (no cytoplasmic granules):

      • Lymphocytes

      • Monocytes

White Blood Cells

  • Neutrophils:

    • Most common type of WBC.

    • Diameter: 9 - 15 µm.

    • Multi-lobed nucleus.

    • Small granules in cytoplasm.

    • Polymorphonuclear cells.

    • Spend 8 - 10 hours in circulation.

    • Involved in bacterial and fungal infections.

  • Eosinophils:

    • Bi-lobed nucleus.

    • Diameter: 9 - 15 µm.

    • Large, strongly staining (orange/red) cytoplasm granules.

    • Circulate for 4-5 hours.

    • Defence against parasitic infections.

    • Dampen allergic responses.

  • Basophils:

    • Least numerous circulating WBCs.

    • Diameter: 10 - 16 µm.

    • 2 - 4 lobes in nucleus.

    • Large cytoplasmic granules (dark staining).

    • Involved in hypersensitivity and inflammatory reactions.

  • Lymphocytes:

    • Second most common WBC in peripheral blood.

    • Diameter: 8 - 10 µm (Small), 12 - 16 µm (Large).

    • Large round nucleus/less cytoplasm.

    • Variable lifespan: few days - years.

    • T-lymphocytes: cell-mediated immunity.

    • B-lymphocytes: humoral immunity.

  • Monocytes:

    • Largest WBC (14 - 20 µm diameter).

    • Kidney-shaped nucleus.

    • Circulate for ~ 10 hours.

    • Exit into tissues and become macrophages.

    • Removal of aged RBCs and other debris.

    • Antigen processing and presentation to T lymphocytes.

Abnormalities

  • Abnormal morphology.

  • Abnormal cell number (abnormal cell counts).

Abnormal Morphology

  • Morphology refers to the “appearance” of a cell.

  • Abnormal cell morphology indicates a change in cell structure/function.

  • Changes to the size and shape of RBCs can indicate:

    • Abnormal erythropoiesis.

    • Inadequate Hb formation.

    • Direct damage after leaving bone marrow (BM).

    • Compensatory erythropoiesis.

  • Change in size of RBC: Anisocytosis.

  • Change in shape of RBC: Poikilocytosis.

Anisocytosis - RBC's - Change in Size

  • Decreased size: Microcytosis.

  • Increased size: Macrocytosis.

Poikilocytosis - RBC's - Change in Shape

  • Elliptocytes:

    • Thin elongated cigar shaped cells.

    • Change to membrane structure.

    • Found in various types of anaemia.

  • Ovalocytes:

    • Oval shaped rather than thin or round.

    • Less pronounced defects.

    • Found in some types of anaemia.

  • Codocytes (target cells):

    • Loss of biconcave shape.

    • Increased surface area:volume ratio.

  • Spherocytes:

    • Loss of biconcave shape - sphere.

    • Decreased surface area:volume ratio.

    • Found in many anaemias.

  • Schistocytes (RBC fragments):

    • Irregularly contracted fragments.

    • Variable appearance.

    • Found in conditions with trauma to RBCs (e.g., burns).

  • Drepanocytes (sickle cells):

    • Elongated, crescent shaped.

    • Sickle cell anaemia.

    • Abnormal haemoglobin (HbS).

  • Acanthocytes (burr cells):

    • Multiple irregular thorny projections.

    • Changes in phospholipid metabolism.

    • Found in liver disease.

  • Dacrocytes (teardrop cells):

    • Teardrop shape.

    • Stretched out of shape - excessive time (spleen).

    • Found in many conditions.

  • Stomatocytes:

    • Oval or rectangular area of central pallor.

    • “Cup”-shaped.

    • Found in liver disease.

  • Echinocytes:

    • Short, evenly spaced pointed projections.

    • Acute blood loss, burns, uraemia - kidney failure.

Immature RBCs

  • Reticulocyte:

    • Immature RBC (newly released to circulation).

    • Contain some RNA but are not nucleated.

    • May show polychromasia.

    • Small percentage of reticulocytes in circulation in normal individuals.

  • Nucleated RBC (nRBC):

    • Developing RBC.

    • Released from bone marrow prematurely.

    • Found in severe anaemias, especially early childhood anaemia.

Other RBC Changes

  • Hypochromasia:

    • “Hypo”- less, “chrom”- colour.

    • Cells stain paler in colour.

    • Enlarged area of central pallor.

    • Decreased Hb content - anaemia.

  • Polychromasia:

    • “Poly” - many, “chrom” - colour.

    • Variable colour [Blue/grey - orange/red].

    • Increased number of immature RBCs.

  • Rouleaux:

    • Stacking of cells due to high protein concentration.

  • Agglutination:

    • Clumping of cells due to antibodies.

RBC Inclusions

  • A number of inclusions may be found in RBCs.

  • Help identify abnormalities/disease.

  • Examples: Malaria, Howell-Jolly Body, Basophilic Stippling.

WBC Abnormal Morphology

  • Many changes to WBC morphology.

  • Help identify abnormalities/disease.

  • Toxic granulation – increased size of granules.

  • Left shift neutrophils - immature.

  • Right shift neutrophils - older.

Total Cell Counts

  • A healthy adult has ~ 5 litres of blood.

  • Cell numbers remain relatively constant in health.

  • Changes occur in disease: e.g., ↑ of WBC in leukaemia (a cancer of blood forming cells), e.g., anaemia ↓ in RBC.

  • The number of cells in circulation is given as a number per unit of volume.

  • Outside these ranges indicate disease.

  • Suffix used to denote the type of change:

    • Increased numbers: -cytosis or -philia.

    • Decreased numbers: -aenia.

Cells

Units

Reference Range

WBC’s

(x 10910^9$$10^9$$/L)

4.0 - 11.0 x 10910^9$$10^9$$/L

RBC’s

(x 101210^{12}$$10^{12}$$/L)

4.50 - 6.50 x 101210^{12}$$10^{12}$$/L (m)



3.80 - 5.80 x 101210^{12}$$10^{12}$$/L (f)

Platelets

(x 10910^9$$10^9$$/L)

150 - 400 x 10910^9$$10^9$$/L

Changes to Blood Cell Numbers

Blood Cell

Increased

Decreased

RBC

Erythrocytosis

Anaemia

WBC

Leucocytosis

Leucopaenia

Neutrophil

Neutrophilia

Neutropaenia

Lymphocyte

Lymphocytosis

Lymphopaenia

Monocyte

Monocytosis

Monocytopaenia

Eosinophil

Eosinophilia

N/A

Basophil

Basophilia

N/A

Platelets

Thrombocytosis

Thrombocytopaenia

All formed


Pancytopaenia

Cell Counts (WBC’s, RBC’s and Platelets)

  • Cell counts are performed to:

    • Determine if disease is present.

    • Monitor the course of disease (treatment).

  • The count should be accurate and precise.

  • Counts are obtained by either of two methods:

    • Manual or.

    • Automated.

  • RCC (number of RBCs per litre of blood): Red Cell Count

  • WCC (number of all WBCs per litre of blood): White Cell Count

Manual Cell Counting

  • All cells in a small volume are counted.

  • The count is extrapolated to give # per L of blood.

  • Cells are counted using a microscope.

  • Blood is diluted (high numbers in whole blood).

  • Counting chamber (haemocytometer).

  • Calibration - international specifications.

NOTE: – Different dilutions and diluents: WHY??

The Counting Chamber

  • Manual cell counts.

  • Blood cells.

  • Others:

    • Bacterial cells in suspension.

    • WBC’s in CSF.

  • Improved Neubauer Counting Chamber.

The Counting Chamber - Dimensions

  • 1 mm x 1 mm (i.e. 1 mm2mm^2$$mm^2$$)

The Counting Chamber - Area for Counting for WCC

  • Each square = 1 x 1 mm.

  • Each square = 1 mm2mm^2$$mm^2$$.

  • i.e. 4 x 1 mm2mm^2$$mm^2$$ = 4 mm2mm^2$$mm^2$$

The Counting Chamber - Calculation

  • Number of cells per litre = mean count x D x DF x 10610^6$$10^6$$ / A (mm2mm^2$$mm^2$$)

    • D = Depth factor - the amount by which the count is multiplied to give the number of cells there would be in 1mm depth. For a 0.1 mm deep chamber (such as the Improved Neubauer Counting Chamber) the Depth Factor would be 10.

    • DF = Dilution Factor (by what factor was the sample diluted)

    • 10610^6$$10^6$$ = Conversion Factor (from mm3mm^3$$mm^3$$ to litres)

    • A = Area of chamber (counted in mm2mm^2$$mm^2$$)

Manual Counting - Sources of Error

  • Technical error:

    • Dilution - small volume of blood is used.

    • Sampling - blood evenly mixed, adequate sample transfer to chamber.

    • Counting - recognise cells correctly.

  • Statistical error:

    • Only a small sub-population of cells are being counted from the total number of cells.

Automated Cell Counting

  • Widely used in laboratories.

  • Full blood count provided in < than 1 minute.

  • Faster, more cells counted, accuracy, precision.

  • Two main principles of cell counting used:

    • Electrical impedance.

    • Light scatter.

  • RBC’s - 1 in 50,000 dilution.

  • WBC’s - 1 in 500 (RBC’s lysed).

Automated Counting - Sources of Error

  • Coincidence error for Impedence counters only – Duplicate cells counted as one cell.

  • Background count.

  • Distribution of cells in diluent.

  • Dilution technique.

  • Contamination.

  • Immersion of sample.

Interpretation

  • The result from a cell count (manual or automated) will be interpreted the same way.

  • Compare result to: reference range.

  • Classify as: low, normal or high.

Example

  • Total number of all WBCs = WCC = 15.4 x 10910^9$$10^9$$/L (Reference range = 4.0 - 11.0 x 10910^9$$10^9$$/L)

  • Result is high i.e. above reference range.

  • “Leucocytosis”.

  • Same approach for all parameters.

The Differential WCC

  • “The Diff”.

  • Count the proportion of the 5 different WBC’s.

  • Manual count = Count 100 consecutive WBC’s.

  • Relative numbers (%) = how many of that type of WBC (N, L, M, E, or B) per 100 WBCs.

  • Then convert the Relative count (%) to Absolute numbers (x 10910^9$$10^9$$/L).

  • Absolute count = % each type of cell x total WCC / 100

Interpretation Example:

  • Example 1: Normal

  • Example 2: Leukocytosis with a marked Lymphocytosis

Additional Information

  • In addition to abnormal cell morphology and WCC/Diff, other information can assist in diagnosis:

    • RCC, platelet count, ESR, PCV, Hb, RBC Indices: MCV, MCH, MCHC

    • More on these, Cross-matching, Coagulation if you study Haematology in 2nd year.


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Haematology Lecture Notes

Haematology

  • Haematology is the study of blood, including:
    • Haemopoiesis
    • Formed elements of blood
    • Haemoglobin
    • Coagulation
    • Blood transfusion / cross matching
  • Blood and bone marrow are intensively studied in haematology.
  • The average adult has approximately 5 litres of blood.
  • Blood is found in:
    • Circulatory system
    • Sinusoids
  • Blood supports the function of body tissues.
  • Blood is a tissue composed of:
    • Formed elements:
      • White blood cells (leucocytes)
      • Red blood cells (erythrocytes)
      • Platelets (thrombocytes)
    • Liquid component: Plasma

Haemopoiesis

  • The production of the formed elements of blood (WBCs, RBCs, and platelets).
    • Erythropoiesis: Production of RBCs.
    • Thrombopoiesis: Production of platelets.
    • Granulopoiesis: Production of granulocytes.
    • Lymphopoiesis: Production of lymphocytes.
    • Monocytopoiesis: Production of monocytes.
  • All cell lines are derived from a single precursor cell.
  • A stem cell differentiates into mature cells under the influence of growth factors.
  • Sites of Haemopoiesis:
    • Foetus: Yolk sac, liver, spleen, bone marrow, lymph nodes.
    • Adult: Bone marrow.

Simplified Cell Lineages

  • Multipotential hematopoietic stem cell (Hemocytoblast) differentiates into:
    • Common myeloid progenitor:
      • Erythrocyte
      • Mast cell
      • Myeloblast:
        • Basophil
        • Neutrophil
        • Eosinophil
        • Monocyte → Macrophage
      • Megakaryocyte → Thrombocytes
    • Common lymphoid progenitor:
      • Small lymphocyte:
        • T lymphocyte
        • B lymphocyte → Plasma cell
      • Natural killer cell (Large granular lymphocyte)

Formed Elements of Blood

  • Red Blood Cell (RBC):
    • Most numerous type of cell in blood.
    • Anuclear.
    • Biconcave disc shape, with an "Area of central pallor".
    • Diameter: 7.2 - 8.0 µm.
    • Lifespan: 120 +/- 20 days.
    • Contains haemoglobin, which transports oxygen and gives RBCs a red colour.
    • Shape allows rapid diffusion of gases and flexibility.
    • Shape maintenance depends on energy and membrane structure (lipid protein carbohydrate).
  • Platelets:
    • Second most numerous type of cell in blood.
    • Discoid shape.
    • Anuclear.
    • Diameter: 3 µm.
    • Small cytoplasmic fragments derived from megakaryocytes.
    • Primary role is the prevention of blood loss.
  • White Blood Cells:
    • Granulocytes (with cytoplasmic granules):
      • Neutrophils
      • Eosinophils
      • Basophils
    • Agranulocytes (no cytoplasmic granules):
      • Lymphocytes
      • Monocytes

White Blood Cells

  • Neutrophils:
    • Most common type of WBC.
    • Diameter: 9 - 15 µm.
    • Multi-lobed nucleus.
    • Small granules in cytoplasm.
    • Polymorphonuclear cells.
    • Spend 8 - 10 hours in circulation.
    • Involved in bacterial and fungal infections.
  • Eosinophils:
    • Bi-lobed nucleus.
    • Diameter: 9 - 15 µm.
    • Large, strongly staining (orange/red) cytoplasm granules.
    • Circulate for 4-5 hours.
    • Defence against parasitic infections.
    • Dampen allergic responses.
  • Basophils:
    • Least numerous circulating WBCs.
    • Diameter: 10 - 16 µm.
    • 2 - 4 lobes in nucleus.
    • Large cytoplasmic granules (dark staining).
    • Involved in hypersensitivity and inflammatory reactions.
  • Lymphocytes:
    • Second most common WBC in peripheral blood.
    • Diameter: 8 - 10 µm (Small), 12 - 16 µm (Large).
    • Large round nucleus/less cytoplasm.
    • Variable lifespan: few days - years.
    • T-lymphocytes: cell-mediated immunity.
    • B-lymphocytes: humoral immunity.
  • Monocytes:
    • Largest WBC (14 - 20 µm diameter).
    • Kidney-shaped nucleus.
    • Circulate for ~ 10 hours.
    • Exit into tissues and become macrophages.
    • Removal of aged RBCs and other debris.
    • Antigen processing and presentation to T lymphocytes.

Abnormalities

  • Abnormal morphology.
  • Abnormal cell number (abnormal cell counts).

Abnormal Morphology

  • Morphology refers to the “appearance” of a cell.
  • Abnormal cell morphology indicates a change in cell structure/function.
  • Changes to the size and shape of RBCs can indicate:
    • Abnormal erythropoiesis.
    • Inadequate Hb formation.
    • Direct damage after leaving bone marrow (BM).
    • Compensatory erythropoiesis.
  • Change in size of RBC: Anisocytosis.
  • Change in shape of RBC: Poikilocytosis.

Anisocytosis - RBC's - Change in Size

  • Decreased size: Microcytosis.
  • Increased size: Macrocytosis.

Poikilocytosis - RBC's - Change in Shape

  • Elliptocytes:
    • Thin elongated cigar shaped cells.
    • Change to membrane structure.
    • Found in various types of anaemia.
  • Ovalocytes:
    • Oval shaped rather than thin or round.
    • Less pronounced defects.
    • Found in some types of anaemia.
  • Codocytes (target cells):
    • Loss of biconcave shape.
    • Increased surface area:volume ratio.
  • Spherocytes:
    • Loss of biconcave shape - sphere.
    • Decreased surface area:volume ratio.
    • Found in many anaemias.
  • Schistocytes (RBC fragments):
    • Irregularly contracted fragments.
    • Variable appearance.
    • Found in conditions with trauma to RBCs (e.g., burns).
  • Drepanocytes (sickle cells):
    • Elongated, crescent shaped.
    • Sickle cell anaemia.
    • Abnormal haemoglobin (HbS).
  • Acanthocytes (burr cells):
    • Multiple irregular thorny projections.
    • Changes in phospholipid metabolism.
    • Found in liver disease.
  • Dacrocytes (teardrop cells):
    • Teardrop shape.
    • Stretched out of shape - excessive time (spleen).
    • Found in many conditions.
  • Stomatocytes:
    • Oval or rectangular area of central pallor.
    • “Cup”-shaped.
    • Found in liver disease.
  • Echinocytes:
    • Short, evenly spaced pointed projections.
    • Acute blood loss, burns, uraemia - kidney failure.

Immature RBCs

  • Reticulocyte:
    • Immature RBC (newly released to circulation).
    • Contain some RNA but are not nucleated.
    • May show polychromasia.
    • Small percentage of reticulocytes in circulation in normal individuals.
  • Nucleated RBC (nRBC):
    • Developing RBC.
    • Released from bone marrow prematurely.
    • Found in severe anaemias, especially early childhood anaemia.

Other RBC Changes

  • Hypochromasia:
    • “Hypo”- less, “chrom”- colour.
    • Cells stain paler in colour.
    • Enlarged area of central pallor.
    • Decreased Hb content - anaemia.
  • Polychromasia:
    • “Poly” - many, “chrom” - colour.
    • Variable colour [Blue/grey - orange/red].
    • Increased number of immature RBCs.
  • Rouleaux:
    • Stacking of cells due to high protein concentration.
  • Agglutination:
    • Clumping of cells due to antibodies.

RBC Inclusions

  • A number of inclusions may be found in RBCs.
  • Help identify abnormalities/disease.
  • Examples: Malaria, Howell-Jolly Body, Basophilic Stippling.

WBC Abnormal Morphology

  • Many changes to WBC morphology.
  • Help identify abnormalities/disease.
  • Toxic granulation – increased size of granules.
  • Left shift neutrophils - immature.
  • Right shift neutrophils - older.

Total Cell Counts

  • A healthy adult has ~ 5 litres of blood.
  • Cell numbers remain relatively constant in health.
  • Changes occur in disease: e.g., ↑ of WBC in leukaemia (a cancer of blood forming cells), e.g., anaemia ↓ in RBC.
  • The number of cells in circulation is given as a number per unit of volume.
  • Outside these ranges indicate disease.
  • Suffix used to denote the type of change:
    • Increased numbers: -cytosis or -philia.
    • Decreased numbers: -aenia.
CellsUnitsReference Range
WBC’s(x 10910^9/L)4.0 - 11.0 x 10910^9/L
RBC’s(x 101210^{12}/L)4.50 - 6.50 x 101210^{12}/L (m)
3.80 - 5.80 x 101210^{12}/L (f)
Platelets(x 10910^9/L)150 - 400 x 10910^9/L

Changes to Blood Cell Numbers

Blood CellIncreasedDecreased
RBCErythrocytosisAnaemia
WBCLeucocytosisLeucopaenia
NeutrophilNeutrophiliaNeutropaenia
LymphocyteLymphocytosisLymphopaenia
MonocyteMonocytosisMonocytopaenia
EosinophilEosinophiliaN/A
BasophilBasophiliaN/A
PlateletsThrombocytosisThrombocytopaenia
All formedPancytopaenia

Cell Counts (WBC’s, RBC’s and Platelets)

  • Cell counts are performed to:
    • Determine if disease is present.
    • Monitor the course of disease (treatment).
  • The count should be accurate and precise.
  • Counts are obtained by either of two methods:
    • Manual or.
    • Automated.
  • RCC (number of RBCs per litre of blood): Red Cell Count
  • WCC (number of all WBCs per litre of blood): White Cell Count

Manual Cell Counting

  • All cells in a small volume are counted.
  • The count is extrapolated to give # per L of blood.
  • Cells are counted using a microscope.
  • Blood is diluted (high numbers in whole blood).
  • Counting chamber (haemocytometer).
  • Calibration - international specifications.

NOTE: – Different dilutions and diluents: WHY??

The Counting Chamber

  • Manual cell counts.
  • Blood cells.
  • Others:
    • Bacterial cells in suspension.
    • WBC’s in CSF.
  • Improved Neubauer Counting Chamber.

The Counting Chamber - Dimensions

  • 1 mm x 1 mm (i.e. 1 mm2mm^2)

The Counting Chamber - Area for Counting for WCC

  • Each square = 1 x 1 mm.
  • Each square = 1 mm2mm^2.
  • i.e. 4 x 1 mm2mm^2 = 4 mm2mm^2

The Counting Chamber - Calculation

  • Number of cells per litre = mean count x D x DF x 10610^6 / A (mm2mm^2)
    • D = Depth factor - the amount by which the count is multiplied to give the number of cells there would be in 1mm depth. For a 0.1 mm deep chamber (such as the Improved Neubauer Counting Chamber) the Depth Factor would be 10.
    • DF = Dilution Factor (by what factor was the sample diluted)
    • 10610^6 = Conversion Factor (from mm3mm^3 to litres)
    • A = Area of chamber (counted in mm2mm^2)

Manual Counting - Sources of Error

  • Technical error:
    • Dilution - small volume of blood is used.
    • Sampling - blood evenly mixed, adequate sample transfer to chamber.
    • Counting - recognise cells correctly.
  • Statistical error:
    • Only a small sub-population of cells are being counted from the total number of cells.

Automated Cell Counting

  • Widely used in laboratories.
  • Full blood count provided in < than 1 minute.
  • Faster, more cells counted, accuracy, precision.
  • Two main principles of cell counting used:
    • Electrical impedance.
    • Light scatter.
  • RBC’s - 1 in 50,000 dilution.
  • WBC’s - 1 in 500 (RBC’s lysed).

Automated Counting - Sources of Error

  • Coincidence error for Impedence counters only – Duplicate cells counted as one cell.
  • Background count.
  • Distribution of cells in diluent.
  • Dilution technique.
  • Contamination.
  • Immersion of sample.

Interpretation

  • The result from a cell count (manual or automated) will be interpreted the same way.
  • Compare result to: reference range.
  • Classify as: low, normal or high.

Example

  • Total number of all WBCs = WCC = 15.4 x 10910^9/L (Reference range = 4.0 - 11.0 x 10910^9/L)
  • Result is high i.e. above reference range.
  • “Leucocytosis”.
  • Same approach for all parameters.

The Differential WCC

  • “The Diff”.
  • Count the proportion of the 5 different WBC’s.
  • Manual count = Count 100 consecutive WBC’s.
  • Relative numbers (%) = how many of that type of WBC (N, L, M, E, or B) per 100 WBCs.
  • Then convert the Relative count (%) to Absolute numbers (x 10910^9/L).
  • Absolute count = % each type of cell x total WCC / 100

Interpretation Example:

  • Example 1: Normal
  • Example 2: Leukocytosis with a marked Lymphocytosis

Additional Information

  • In addition to abnormal cell morphology and WCC/Diff, other information can assist in diagnosis:
    • RCC, platelet count, ESR, PCV, Hb, RBC Indices: MCV, MCH, MCHC
    • More on these, Cross-matching, Coagulation if you study Haematology in 2nd year.