Laboratory Investigation of WBC Flashcards
What is the normal Hb count in a FBC?
Normal Male 130 - 180 g/L Normal Female 120 – 160 g/L Lower in females due to menstruation
What is the normal WBC count value?
Normal Adult 4.0 - 11.0 x 109 / L
What is the normal platelet count?
Normal Adult 150 - 400 x 109 / L (Plt)
How can the WBC count differ from the normal?
- Neutrophil and lymphocytes should account for 90-95% of your WBC count
- Neutrophils (bacterial infections) and lymphocytes (viral infections)
- Viruses will supress neutrophils
- Monocytes → involved in unusual infections such tuberculosis and are also raised in haematological malignancies
- Eosinophils → elevated levels can indicate presence of parasites (worms, parasites, helminths) or allergic reactions (such as in a skin rash or asthma) as well as some autoimmune diseases
- Basophils → elevated levels are usually due to haematological malignancy
- Note: There should hardly be any basophils in your blood
- There is no such thing as a low basophil/ neutrophil count
Elevated basophils
Due to allergic reaction or parasites
Elevated monocytes
Involved in unusal infections such as TB also raised in haematological malignancies
Elevated Basophils
elevated levels are usually due to haematological malignancy
What type of WBC is this, What are its features?
NEUTROPHIL
- Involved in innate response, first cell to site of infection, can engulf pathogens
- Known as PML (polymorphonuclear leucocytes)
- Contain 2-5 lobes
- Contain granules
- Bacterial infection results in neutrophilia
What type of WBC is it, Describe its features
- Large rounded nucleus with little cytoplasm
- Contain NO GRANULES
- Some viruses can supress the bone marrow resulting in lymphopenia and neutropenia
- E.g. in HIV CD4-T-lymphocyte becomes infected causing a marked lymphopenia
- Some viruses can supress the bone marrow resulting in lymphopenia and neutropenia
- Blue cytoplasm
What is the function of T-cells?
Involved in cell mediated immunity → essentially eats up a cell
- CD4+ T-Helper Cells
- CD8+ Cytotoxic T-Cells
What is the function of B-cells?
Involved in Humoral Immunity → Antibody production
What is the function of Natural Killer Cells? (NKs)
Are part of the Innate Immune System, attacking virally infected cells and tumour cells
What type of cell is this? What are its functions?
NATURAL KILLER CELLS
- Only lymphocyte which contains granules
- Nucleus is not lobed and the cytoplasm is paler in comparison to B and T lymphocytes
Involved in attacking virally infected cells + tumour cells
What type of WBC is this? What is its role?
- Largest WBC
- Contain a dumbbell/ kidney bean shaped nucleus
- Contain 2 lobes only
- Contain a VACUOLE → artefact of blood coagulation
- Are precursors of macrophages
What type of cell is this? What are its functions?
- Similar nucleus to a neutrophil
- Contain a large dense orange granules
- Involved in fighting parasitic infections and allergic reactions
What type of cell is this? What role does it play?
- Thicker, dark purple, blue/black granules because they contain acidic heparin
- Precursors of mast cells
What cells are granulocytes?
Neutrophils, Eosinophils, Basophils
What cells are mononuclear leucocytes?
- Lymphocytes (sky blue cytoplasm)
- Monocytes (blue/grey cytoplasm + vacuole)
What is the normal range for neutrophils?
What term is used for neutrophils outside the normal range?
Normal Adult Neutrophils → 2.0 - 7.5 x 109 / l
- Neutrophilia: Increase in neutrophils
- Neutropenia: Decrease in neutrophils
List some changes that can occur in neutrophils
-
Toxic Granulation
- Look similar to basophils however in basophils the granules obscure the nucleus
-
Shifting to the left
- Increase in immature neutrophils
-
Shifting to the right
- Increase in mature/overage neutrophils
-
Hypersegmented Neutrophil
- Associated with megaloblastic anaemia, commonly caused due to folic acid or vitamin B12 deficiency (inc. pernicious anaemia)
-
Dohle Body
- Light blue Oval in cytoplasm
-
Tiny Vacuole
- Can develop in infections
- MONOCYTES ALWAYS CONTAIN VACUOLES
- Can develop in infections
What normal physiological reactions can cause neutrophilia?
- Post-operative
- Pregnancy
What are other causes of neutrophilia?
- Bacterial Infection
- Inflammation e.g. vasculitis, myocardial infarction
- Carcinoma
- Steroid treatment (neutrophils contain steroid receptors)
- Myeloproliferative disorders
- Treatment with myeloid growth factors e.g G-CSF
How do you investigate neutrophilia?
- FBC and differential white cell count
- Blood film examination
- Bacterial culture screen for infection
- Ask about steroid therapy
Once these have been ruled out
- Bone marrow examination + chromosome analysis for chronic myeloid leukaemia – Philadelphia chromosome: à translocation between chromosomes 9 and 22
- Molecular analysis for BCR-ABL oncogene
What is the characteristic difference between acute and chronic leukaemia?
Chronic leukaemia occurs due to mature cells and presents more slowly → often patients will not know they have leukaemia
Acute leukaemia blast cells proliferate, they are aggressive and rapidly progressive hence symptoms are developed much quicker
What are causes of neutropenia?
- Viral infection (viruses will supress neutrophils)
- Drug Induced e.g sulponamides
- Note: If you dont know what to write put drugs
- Radiotherapy and Chemotherapy
- Part of a pancytopenia in bone marrow failure (aplastic anaemia) or infiltration e.g. leukaemia
- Racial benign ethnic neutropenia
What are causes of eosinophilia?
- Allergic Diseases
- Asthma/ Hay Fever
- Parasitic infections
- HODGKINS LYMPHOMA
- Myeloproliferative diseases e.g chronic myeloid leukaemia
- Drug sensitivity
Investigation of Eosinophilia
- FBC and differential white cell count
- Blood film examination
- Stool examination for ova and parasites
What are causes of monocytosis?
- Remember monocytes contain vacuoles, no granules and are involved in unusual infections like TB
Causes are:
- Tuberculosis
- Acute and Chronic monocytic and myelomonocytic leukaemia
- Malaria
What is the investigation of monocytosis?
- FBC and differential white cell count
- Blood film examination:
- For abnormal white blood cells
- For malarial parasites
- Bone marrow examination - leukaemia
- TB cultures
What are the causes of lymphocytosis?
Bacterial Infection (but mainly a neutrophilia)
- Viral Infections
- e.g.
- Hepatitis
- Mumps
- Rubella
- Pertussis
- Glandular Fever
- (Infectious Mononucleosis)
- Leukaemias (originate from bone marrow) and lymphomas (originate from lymph glands)
What is the investigation of lymphocytosis?
- FBC and differential white cell count
- Blood film examination
- Is there the presence of atypical mononuclear cells?
- Glandular Fever caused by EBV
- Infectious Mononucleosis, Kissing Disease
- Monospot, Paul Bunnell Test, Clearview Infectious Mononucleosis Test
- Glandular Fever caused by EBV
What type of cell is this?
What is caused due to?
These are lymphocytes with some morphological properties of monocytes.
- These indicate a viral disease – mononucleosis
- This occurs due to the Epstein-Barr Virus which affects parenchymal organs and cells of the lymphoid tissue
What can we do to investigate if lymphocytosis is due to chronic lymphocytic leukaemia or lymphoma?
Immunophenotyping to determine if lymphocytes are:
- B-cells: Demonstrate clonality by light chain restriction
- or
- T-cells: Demonstrate clonality by T-cell Receptor Gene Rearrangement Studies
