FBC And Film

Question 1

What is the Full Blood Count, FBC

What must samples be mixed with and why

Answer 1

A panel of tests performed on a blood sample to determine whether or not any abnormalities are present

Must be mixed with EDTA, this chelates Ca ions, preventing clotting

Question 2

Describe 3 Analyser techniques

Answer 2

Spectrophotometry: Amount of light absorbed by sample is proportional to amount of absorbent material within

Flow Cytometry: Single line of cells passes through a light beam, forward scatter counted, more scatter= bigger cell

Flow Cytometry Differential: Forward scatter measures size, side scatter measures intracellular complexity (E.g granules)

Question 3

What is Haematocrit? How is it measured

Answer 3

Proportion of whole blood that consists of RBCs

MCV* Red cells per litre

Question 4

What is Haemoglobin concentration

Answer 4

Amount of Hb in blood

Hb mass/ plasma volume after lysis of RBCs

Question 5

What is RCC

Answer 5

Number of RBCs in a given blood volume

Question 6

What is MCH

How is it calculated

Answer 6

Mean Cell Haemoglobin: Average amount of Hb in an RBC

• Divide Hb conc. in a given blood volume by no. of red cells

Question 7

What is the reticulocyte count
How are they identified

Why are they used

Answer 7

Measurement of number of immature RBCs
Identified by binding to rRNA

To evaluate different kinds of anaemia

Question 8

What is a blood film

When is a blood film required (4 occasions)

Answer 8

A single layer of cells used to inspect blood cell morphology

• Significant results outside the normal range
• Significant change within the normal range
• Abnormalities
• Parasites

Question 9

Compare;

1. Microcyte and macrocyte
2. Hypochromic vs hyperchomic

Answer 9

Microcyte- Small RBCs
Macrocyte- Large RBCs

Hypochromic- Pale RBCs (Less Hb)
Hyperchromic- Dense RBCs (More Hb)

Question 10

What is;

1. Anisocytosis
2. Poikiolocytosis
3. A Target cell (Codocytosis)
4. Stomatocytosis

Answer 10

1. Greater than normal variation in RBC size
2. Greater than normal variation in RBC shape
3. Hb concentrated at periphery and centre of RBC
4. RBC with slit like stroma

Question 11

What is a;

1. Schistocyte
2. Acanthocyte
3. Echinocyte

Answer 11

1. Fragment of RBC
2. RBC with small number of irregular spurs
3. RBC with large number of irregular spurs

Question 12

Which 5 cells can be recognised in Differential WBC counts

Answer 12

Neutrophils
Basophils 
Eosinophils
Lymphocytes
Monocytes

Question 13

Which FBC parameter is the most aberrant

Why they can be easily distinguished from RBCs and WBCs

Answer 13

Platelets

Smaller than RBCs, WBCs so smaller signal produced

Question 14

Name 2 conditions that cause low MCV

Name 4 conditions that cause high MCV

Answer 14

Low iron anaemia
Thalassaemia

Liver disease
Alcohol, smoking
Haemolytic anaemia

Question 15

Name 1 time where Reticulocyte count is reduced

Name 3 times where Reticulocyte count is increased

Answer 15

Bone marrow failure

Recent blood loss
Bone marrow recovery
Haemolytic anaemia

Question 16

How does a B12 deficiency affect;

1. Hb
2. RCC
3. MCH
4. MCV
5. Hct (Haematocrit)
6. Reticulocyte count

Answer 16

1. Reduced Hb
2. Reduced RCC
3. Increased MCH
4. Increased MCV
5. Decreased Hct
6. Decreased Reticulocyte count