Haematology & Anemia Flashcards

1
Q

List the types of laboratory blood tests that can be used

A

Haemocytometer (RBC count)
Microhematocrit
Microscopic examination of blood smears

Automated analysers
-Coulter principle
-Laser cell counters
-Quantitative buffy coat analysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

List the types of laboratory blood tests that can be used

A

Haemocytometer (RBC count)
Microhematocrit
Microscopic examination of blood smears

Automated analysers
-Coulter principle
-Laser cell counters
-Quantitative buffy coat analysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe the blood test microhaematocrit

A

Measures the ratio of the volume occupied by packed red blood cells to the volume of the whole blood
This equals the Packed cell volume or PCV

Rapid & cheap in house test that gives large amount of information

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Other than PCV what other information can microhaematocrit tell you

A

indications to dehydrations, jaundice, haemolysis, any artefacts, lipaemia, leukocytosis or thrombocytosis’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe the use of automated cell counters

A

Dependent Coulter principle (electrical technique): to enumerate and identify blood cell populations

  • A stream of cells passes through an aperture between two chambers, across which there is an electrical current.
  • Passing cells disrupt the electrical flow, causing a pulse:
    Amplitude is proportional to cell volume
    Pulse frequency provides information of cell number

Absorbance: to measure haemoglobin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Outline the production of size destitution plots by use of cell counters

A

Histograms plotting the cell number against cell size.

Measured values

-Red blood cells - absolute number per litre

-Mean corpuscular volume (MCV) - the average volume of the red cells (fl)

-Platelets - absolute number per litre

-White blood cell counts - absolute number per litre

-Haemoglobin - The amount of haemoglobin in the blood (g/l)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Explain the derivation and meaning of mean cell volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC)

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Explain the derivation and meaning of packed cell volume (PCV) and outline the calculation

A

Hematocrit (Hct) = packed cell volume (PCV)
This is the fraction of whole blood volume that consists of red blood cells.

Calculated Hct/PCV:
Hct/PCV = MCV x RBC count/100

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Explain the derivation and meaning of mean corpuscular hemoglobin (MCH) and outline the calculation

A

The average amount of hemoglobin per red blood cell, in picograms.

MCH pg = Hb x10/RBC count

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Explain the derivation and meaning of corpuscular hemoglobin concentration (MCHC) and outline the calculation

A

The average concentration of hemoglobin in the cells relative to size/volume of cell.

MCHC g/dl = Hb x100/Hct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Discuss the limitation pf automated systems

A

They will not give reliable differential white cell counts (especially if there are abnormalities).
Even laser based in-clinic analysers and even combined laser/impedance analysers are also not perfectly reliable.

Occasionally small RBCs will be undercounted and counted as platelets.

Large platelets may get counted as red cells.

Can’t ID RBC morphology, WBC morphology or blood parasites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

List some common problems with blood samples

A

Correct tube selection (correct anti-coagulant for the test requested)
Clotting
Haemolysis
Appropriate tube fill
Lipaemia
Labelling (Species!)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Discuss the use of the skill microscopic examination of blood smears and the benefit of microscopic examination

A

Differential leukocyte counts
diversity of leukocyte patterns in cats & dogs

Erythrocyte and leukocyte morphology

Presence of any abnormal cells & parasites

Platelet counts – manual estimate to confirm results from automatic analysis

Send with EDTA sample for blood analysis
To distinguish the effect of “sample aging” during transport and genuine diagnostic findings

Quick & low cost diagnostic tool which is often used by charities such as PDSA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Explain use of erythrocyte sedimentation rate blood test

A

Erythrocyte sedimentation rate

An increase in ESR is a non-specific change in many diseases

The sedimentation rate is probably due to changes in the plasma that encourage agglutination
Which lead to larger aggregates that sediment more rapidly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe the use of erythrocyte sedimentation rate in different species

A

Horses –ESR too high in healthy animals to notice increase due to disease

Ruminants – no increase due to disease

Dogs 5-10 mm/h
Pigs 2-14 mm/h

-during disease these levels can rise more than 10fold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

List two other types of blood tests which can be used and outline what they measure

A

TIBC (total iron binding capacity)

O2/CO2

-Indirect measure of amount of transferrin in the blood

17
Q

Describe the condition of anemia and outline what may cause it

A

Condition in which the capacity of the blood to transport oxygen is reduced

  • Reduced number of circulating erythrocytes
  • Reduced amount of haemoglobin per erythrocyte
    -Both
18
Q

List the variables used to identify anemia in an animal

A

Defined by 3 basic variables:
-Total Haemoglobin
-PCV (packed cell volume) or haematocrit
-RBC count

19
Q

Describe how anemia is characterized

A
  1. Cell size
    -Macrocytic
    -Normocytic
    -Microcytic
  2. Haemoglobin content
    -Hypochromic
    -Normochromic
    -Hyperchromic (viewed with caution)

Bone marrow response

  1. Reticulocyte count
    -Regenerative
    -Non-regenerative
20
Q

How do characteristic of anemia relate to blood values?

A

MCV (Cell size/volume)
Increase - macrocytic
Decrease - microcytic

MCHC (Haemoglobin content)
Low- Hypochromic
High - Hypochromic (artificial result)

Reticulate count
Normal (low)- nonregenerative
Increase - regenerative

21
Q

Identify clinical causes of lysis of erythrocytes

A

-transfusion reaction
-bacterial infections
-neonatal erythrolysis

22
Q

Identify clinical causes of losses of blood

A

-internal bleeding from clotting disorder
-bleeding intestinal; neoplasm or ulcer
-severe hookworm infestations
-trauma causing haemorrhage
-severe flea infestation

23
Q

Identify different types of anaemia

A

Loss of blood
Lysis of erythrocytes
Reduced production of erythrocytes

24
Q

Identify clinical causes of reduced production of erythrocytes

A

-iron deficiency
-lead poisoning
-lymphoma leukaemia
-chronic renal disease
-viral disease