[W2] The full blood count

Question 1

What are the main components of a Full Blood Count (FBC)?

Answer 1

WBC + differential, RBC, Hb, Hct, MCV, MCH, MCHC, Platelets.

Question 2

What does the WBC differential count measure?

Answer 2

Neutrophils, Lymphocytes, Monocytes, Eosinophils, Basophils.

Question 3

How is Haematocrit (Hct) calculated?

Answer 3

Hct = RBC x MCV / 1000.

Question 4

What is Mean Cell Volume (MCV)?

Answer 4

MCV is the average volume of an RBC.

Question 5

What is Mean Cell Haemoglobin (MCH)?

Answer 5

MCH = Hb (g/l) ÷ RBC (picograms per RBC).

Question 6

What is Mean Corpuscular Haemoglobin Concentration (MCHC)?

Answer 6

MCHC = Hb (g/l) ÷ Hct (amount of Hb in 1L of RBCs).

Question 7

What does the platelet count measure?

Answer 7

The number of platelets in the blood.

Question 8

what is the normal range of WBC x10⁹/L for female and males?

Answer 8

female: 4.0-10.0
male: 4.0-10.0

Question 9

what is the normal range of Haemoglobin g/L for female and males?

Answer 9

female: 115-160
male: 125-180

Question 10

what is the normal range of Platelets x10⁹/L for female and males?

Answer 10

female: 150-400
male: 150-400

Question 11

what is the normal range of RBC x10¹²/L for female and males?

Answer 11

female: 3.5-5.5
male: 4.2-6.2

Question 12

what is the normal range of Haematocrit L/L for female and males?

Answer 12

female: 0.350-0.460
male: 0.390-0.520

Question 13

what is the normal range of MCV fL for female and males?

Answer 13

female: 78-98
male: 78-98

Question 14

what is the normal range of MCH pg for female and males?

Answer 14

female: 25.0-33.0
male: 25.0-33.0

Question 15

what is the normal range of MCHC g/L for female and males?

Answer 15

female: 315-360
male: 315-360

Question 16

what is the normal range of Neutrophils x 10⁹/L for female and males?

Answer 16

female: 1.8-7.5
male: 1.8-7.5

Question 17

what is the normal range of Monocytes x 10⁹/L for female and males?

Answer 17

female: 0.2-0.8
male: 0.2-0.8

Question 18

what is the normal range of Eosinophils x 10⁹/L for female and males?

Answer 18

female: 0-0.4
male: 0-0.4

Question 19

what is the normal range of Basophils x 10⁹/L for female and males?

Answer 19

female: 0-0.2
male: 0-0.2

Question 20

what is the normal range of Lymphocytes x 10⁹/L for female and males?

Answer 20

female: 1.5-4.0
male: 1.5-4.0

Question 21

What is RDW?

Answer 21

Red Cell Distribution Width (RDW) = CV of RBC volume.

Question 22

What does the immature granulocyte count measure?

Answer 22

The number of immature granulocytes in the blood.

Question 23

What does the nucleated RBC count indicate?

Answer 23

Presence of immature RBCs in circulation.

Question 24

What does the reticulocyte count measure?

Answer 24

The number of young RBCs, indicating bone marrow activity.

Question 25

What do FBC alerts ("flags") indicate?

Answer 25

Possible blasts, abnormal lymphocytes, or platelet morphology.

Question 26

what 3 reason would you do a full blood count?

Answer 26

- Suspicion of disease especially anaemia, infection, malignancy - Monitoring of known disease or treatment that impacts blood cells - “Defensive medicine”

Question 27

Who first described RBCs and when?

Answer 27

Jan Swammerdam, 1678.

Question 28

Who independently described WBCs in 1843?

Answer 28

Gabriel Andral & William Addison.

Question 29

Who first described platelets and when?

Answer 29

Max Schultz, 1865.

Question 30

Who invented the haemocytometer and when?

Answer 30

Louis-Charles Malassez, 1874.

Question 31

Who characterized "microphages" and "macrophages" in 1882?

Answer 31

Ilya Metchnikoff.

Question 32

What did Dmitri Romanowsky develop in 1890?

Answer 32

A stain (methylene blue + eosin) enabling WBC differential count.

Question 33

Who developed the first electronic particle counter and when?

Answer 33

Wallace Coulter, 1953.

Question 34

what is a haemocytometer slide used for?

Answer 34

manual blood cell counting

Question 35

How is Packed Cell Volume (PCV) calculated?

Answer 35

(Height of RBC column ÷ Height of blood column) × 100.

Question 36

What happens to blood after centrifugation?

Answer 36

Plasma at the top, RBCs at the bottom.

Question 37

What is the manual version of Haematocrit (Hct)?

Answer 37

Packed Cell Volume (PCV) in %.

Question 38

How is PCV measured manually?

Answer 38

Blood in a sealed capillary tube is centrifuged.

Question 39

When was the haemoglobinometer developed?

Answer 39

Circa 1925.

Question 40

what are the 5 benefits of automated haemoglobinometer?

Answer 40

- capacity (workload) - time - accuracy - precision - cost

Question 41

What are the two principal methods of cell counting automation?

Answer 41

Aperture impedance and optical

Question 42

Can aperture impedance and optical methods be used together in cell counting?

Answer 42

Yes, they may be used in combination.

Question 43

What is the typical aperture size in the aperture impedance principle?

Answer 43

50-100μm, depending on particle size

Question 44

What does the aperture impedance method measure?

Answer 44

Changes in electrical impedance

Question 45

In aperture impedance, what does the number of impedance changes indicate?

Answer 45

Concentration of particles

Question 46

In aperture impedance, what does the amplitude of impedance change indicate?

Answer 46

Particle volume

Question 47

What issue does a vortex behind the aperture cause in aperture impedance counting?

Answer 47

It can affect accuracy and particle flow.

Question 48

Where does the detection zone extend in aperture impedance counting?

Answer 48

On either side of the aperture

Question 49

How does cell orientation affect sizing in aperture impedance counting?

Answer 49

Sizing is influenced by the orientation of the cell as it passes through the aperture.

Question 50

What effect do shear forces near the aperture have on cells?

Answer 50

They can deform cells, affecting measurement accuracy.

Question 51

Why can't aperture impedance counting be used for mixed cell populations like RBCs and platelets?

Answer 51

The method cannot differentiate between different cell types.

Question 52

What is the main objective of sheath stream focusing (hydrodynamic focusing)?

Answer 52

To achieve a stream of separate cells for better sizing and counting of mixed populations.

Question 53

What errors occur if cells are in different planes during counting?

Answer 53

Sizing and identification errors.

Question 54

What happens if cells pass through the detector side by side?

Answer 54

Coincidence occurs, causing sizing and counting errors.

Question 55

How does a vortex in the counting zone affect measurements?

Answer 55

It causes sizing and identification errors.

Question 56

In which cell counting methods is sheath stream focusing used?

Answer 56

Aperture impedance and optical counting.

Question 57

how are WBCs differentiated?

Answer 57

based on cell size

Question 58

What is the purpose of differential lysis in cell counting?

Answer 58

To selectively lyse different WBC populations by shrinking their cytoplasm.

Question 59

Which type of WBC is resistant to acid lysis?

Answer 59

Basophils.

Question 60

Which type of WBC is resistant to alkaline lysis?

Answer 60

Eosinophils.

Question 61

In which cell counting methods is differential lysis used?

Answer 61

Aperture impedance and optical counting.

Question 62

In optical cell counting, what is the number of light pulses proportional to?

Answer 62

Cell count (WBC, RBC, and platelets).

Question 63

What does narrow-angle forward scatter indicate in optical cell counting?

Answer 63

Cell volume.

Question 64

What does wider-angle scatter indicate in optical cell counting?

Answer 64

Refractive index, used for assessing Hb concentration in RBCs or granularity in WBCs.

Question 65

What additional measurements can be incorporated into optical cell counting?

Answer 65

Fluorescence (after staining) and light absorption (e.g., peroxidase staining).

Question 66

What does SFL (side fluorescence) measure in cell counting?

Answer 66

DNA and RNA stain.

Question 67

What does FSC (forward scatter) indicate?

Answer 67

Cell size.

Question 68

What does SSC (side scatter) indicate?

Answer 68

Granularity.

Question 69

What technique does the WBC/Baso channel use to differentiate basophils?

Answer 69

Acid differential lysis, which shrinks non-basophil WBCs.