Lab Investigation Of The Full Blood Count And White Cell Disorders

Question 1

What is Normal Haemopoiesis?

Answer 1

Blood cell production in bone marrow of long bones

Question 2

What are the first steps in normal haematopoiesis?

Answer 2

Multipotent haematopoietic stem cell divides into a lymphoid or myeloid stem cell

Question 3

What do lymphoid stem cells divide into?

Answer 3

Lymphoblast
→ natural killer cells
Or
→ T and B lymphocytes

Question 4

What does a myeloid stem cell divide into?

Answer 4

• Megakaryoblast
• Proerythroblast
• Myeloblast
• Monoblast

Question 5

What do monoblasts differentiate into?

Answer 5

Monocytes

Question 6

What do myeloblasts differentiate into?

Answer 6

Basophil
Neutrophil
Eosinophil

Question 7

What do proerythroblasts differentiate into?

Answer 7

Reticulocyte → erythrocyte

Question 8

What do megakaryoblasts differentiate into?

Answer 8

• Megokaryocytes
• Platelets

Question 9

What is in a full blood count?

Answer 9

• Hb concentration
• HCt
• MCV
• MCH
• RDW
• Reticulocyte count

Question 10

What is HCt?

Answer 10

• Haematocrit → Percentage of blood volume as RBC

Question 11

What is MCV?

Answer 11

• Mean corpuscular volume
• → Average size of RBC

Question 12

What is MCH?

Answer 12

• Mean corpuscular haemoglobin =
• avg Hb content of RBC

Question 13

What is RDW?

Answer 13

• Red cell distribution width =
• range of deviation around RBC size

Question 14

What is in the white blood cell count?

Answer 14

Total WBC and breakdown of:

• Neutrophils
• Lymphocytes
• Monocytes
• Basophils
• Eosinophils

Question 15

What of the platelets are measured in a FBC?

Answer 15

Platelet count and size

Question 16

Define Anisocytosis

Answer 16

Different sizes of RBCs.

Question 17

Define Poikilocytosis

Answer 17

Different shapes of RBCs

Question 18

Define Polychromasia

Answer 18

RBCs have blueish colour in cytoplasm due to increased RNA

Question 19

What does a blood film do?

Answer 19

Confirms number of cells and morphology

→ are the cells ‘normal’?

→ are there any cells present that shouldn’t be

Question 20

What do we look for in White blood cells?

Answer 20

• Numbers → Too many? Too few?
• Normal morphology → Dysplastic features?
• Immature cells → Myelocytes, precursors
• Abnormal cells → blasts, atypical lymphoid cells
• Inclusions

Question 21

What do we look for in red cells?

Answer 21

• Size
• Colour → Hb Content
• Shape
• Polychromasia?
• Inclusions

Question 22

How is a FBC processed?

Answer 22

Using optical scanner methods and presented in a cytogram

Question 23

How are things shown in a cytogram?

Answer 23

Populations of cells are displayed in distinct clusters

Question 24

What are the advantages of an automated haematology machine?

Answer 24

• Efficient and cost effective
• Accurate and precise
• Multiple tests at a time
• Reduced labour requirements
• Accurate determination of red cell numbers

Question 25

What are the disadvantages of an automated haematology machine?

Answer 25

• When results are flagged, it needs labour intensive manual examination of blood smear
• Comments on red cell morphology cannot be generated
• Platelet clumps are counted as one, so low count
• Expensive and high running cost

Question 26

What is tear drop poikilocytosis seen in?

Answer 26

Myelofibrosis or bone marrow infiltration

Question 27

What do malarial antigen tests do?

Answer 27

Malarial antigen test (BinaxNOW) tests for the type of parasite. Horseradish peroxidase tests.

T1 – plasmodium falciparum

T2 – plasmodium malariae, P.ovale, and P.vivax – cannot distinguish between these 3 but can distinguish P.falciparum from non-falciparum species