[W2] Full Blood Count

Question 1

What is a Full Blood Count (FBC)?

Answer 1

A test that measures and calculates multiple blood cell parameters including RBC, WBC, Hb, Hct, platelets, MCV, MCH, and MCHC.

Question 2

Why is FBC important?

Answer 2

Detects anaemia, infections, blood cancers; monitors treatment; part of routine and emergency diagnostics.

Question 3

What does WBC measure?

Answer 3

Total white blood cell count (×10⁹/L).

Question 4

What is RBC?

Answer 4

Red blood cell count (×10¹²/L).

Question 5

What is Hb?

Answer 5

Haemoglobin concentration (g/L) — reflects oxygen-carrying capacity.

Question 6

What is Haematocrit (Hct)?

Answer 6

Proportion of blood made up of red cells (L/L); calculated as Hct = (RBC × MCV)/1000.

Question 7

What is MCV?

Answer 7

Mean Cell Volume — average volume of red cells (fL).

Question 8

What is MCH?

Answer 8

Mean Cell Haemoglobin — average mass of Hb per red cell (pg); calculated as Hb ÷ RBC.

Question 9

What is MCHC?

Answer 9

Mean Corpuscular Haemoglobin Concentration — Hb concentration per litre of red cells (g/L); calculated as Hb ÷ Hct.

Question 10

What are platelets?

Answer 10

Cell fragments involved in clotting (×10⁹/L).

Question 11

What are the normal ranges for WBC in adults?

Answer 11

4.0–10.0 ×10⁹/L

Question 12

What are the normal ranges for Hb in females?

Answer 12

115–160 g/L

Question 13

What are the normal ranges for Hb in males?

Answer 13

125–180 g/L

Question 14

What are the normal ranges for platelets in adults?

Answer 14

150–400 ×10⁹/L

Question 15

What are the normal ranges for RBC in females?

Answer 15

3.5–5.5 ×10¹²/L

Question 16

What are the normal ranges for RBC in males?

Answer 16

4.2–6.2 ×10¹²/L

Question 17

What are the normal ranges for Hct in females?

Answer 17

0.35–0.46

Question 18

What are the normal ranges for Hct in males?

Answer 18

0.39–0.52

Question 19

What are the normal ranges for MCV?

Answer 19

78–98 fL

Question 20

What are the normal ranges for MCH?

Answer 20

25–33 pg

Question 21

What are the normal ranges for MCHC?

Answer 21

315–360 g/L

Question 22

What is RDW?

Answer 22

Red Cell Distribution Width — variation in RBC size (CV of RBC volume).

Question 23

What are immature granulocyte and nucleated RBC counts used for?

Answer 23

Indicators of stress on marrow or severe infection.

Question 24

What are reticulocytes?

Answer 24

Immature red cells — used to assess bone marrow response.

Question 25

What tool is used for manual counting?

Answer 25

Haemocytometer.

Question 26

What is packed cell volume?

Answer 26

Manual version of haematocrit; calculated after centrifugation: PCV (%) = (Height of RBC column / Height of total blood column) × 100.

Question 27

What are the two main automation methods for cell counting?

Answer 27

* Aperture Impedance (Coulter principle) * Optical/Flow Cytometry

Question 28

How does aperture impedance work?

Answer 28

Cells pass through an aperture; changes in electrical impedance indicate cell size and count.

Question 29

What are limitations of aperture impedance?

Answer 29

* Orientation errors * Vortex formation * Difficulty counting mixed populations

Question 30

What is hydrodynamic focusing?

Answer 30

Aligns cells in a single stream to improve counting accuracy.

Question 31

How does optical counting work?

Answer 31

Uses light scatter and fluorescence to measure cell count, volume, granularity, and Hb concentration.

Question 32

How are WBCs differentiated in automation?

Answer 32

By size (forward scatter), granularity (side scatter), and light absorption (e.g., peroxidase staining).

Question 33

What is differential lysis used for?

Answer 33

Selectively shrinks certain WBC types for better identification (e.g., acid lysis for basophils).

Question 34

What might low Hb and RBC with normal MCV suggest?

Answer 34

Normocytic anaemia.

Question 35

What might high MCV and low RBC indicate?

Answer 35

Macrocytic anaemia (e.g., B12 or folate deficiency).

Question 36

What does high lymphocyte count in a young patient suggest?

Answer 36

Viral infection or possibly glandular fever.

Question 37

What might raised neutrophils + platelets indicate?

Answer 37

Inflammation or infection.