Laboratory Investigation of the Full Blood Count & WBC disorders Flashcards
How does normal haemopoiesis occur (RECAP)
- Produced in the bone marrow of long bones and mature within peripheral blood
- Starts with multipotent stem cells which divide to self-renew themselves and become either myeloid or lymphoid stem cells in response to growth factors.
- Lymphoid stem cells give rise to T cells, B cells and natural killer cells
- Myeloid stem cells give rise to: megakaryocytic and platelets, Erythrocytes, basophils, neutrophils, eosinophils and monocytes
What do we look for in a Full blood count for red blood cells?
- Hb: concentration of Haemoglobin
- Hct: Percentage of blood volume as RBC
- MCV: Average size of RBC
- MCH: Average haemoglobin content of RBC
- RDW: Range of deviation around RBC size
- Reticulocyte count
- Blood film
What do we look for in a Full blood count for white blood cells?
- Total WBC and differential
- Neutrophils, lymphocytes, monocytes,
- basophils, eosinophils
What do we look for in a Full blood count for platlets
Platelet count and size
What morphological indicators do we look for in a FBC for RBC
- Size – big or small - anisocytosis
- Colour – Hb content
- Shape: round, TDP, irregular, elliptocytes - poikilocytosis
- Polychromasia
- Inclusions
What morphological indicators do we look for in a FBC for WBC
- Numbers – too many, too few
- Normal morphology – dysplastic features
- Immature cells – myelocytes, precursors,
- Abnormal Cells – blasts, atypical lymphoid cells
- Inclusions
How do we process full blood counts
FBC processed using optical scatter methods and presented in cytogram where population of cells are displayed in distinct cluster.
If the differentials are not displayed correctly, this alerts operator to refer the sample for a blood smear to be examined; as shown on left of cytogram with immature granulocytes in the neutrophil region
What are the advantages of using a haematology analyser to do FBCs
- Efficient and cost effective:
processing of large number of samples. - Accuracy and precision of quantitative blood test
- Ability to perform multiple test on single platform
- Reduced labour requirements
- Invaluable for accurate determination of red cell indices; e.g. MCV
What are the disadvantages of using a haematology analyser to do FBCs
- Flagging of laboratory test results demand labour intensive manual examination of blood smear.
- Comments on red cell morphology cannot be generated.
- Platelet clumps are counted at single, so low count.
- Expensive with high running cost
Lecture Slides have blood film pictures for each condition
Lecture Slides have blood film pictures for each condition