heamatology Flashcards
MCV
Mean cell volume
MCH
Mean corpuscular haemoglobi
MCHC
Mean corpuscular haemoglobin concentration
takes into acound size of cell
RDW
Red cell distribution width
Wintrobe’s Erythrocytes Indices
Used to characterised erythrocytes in peripheral
circulation
* Represent average values of all RBC’s
* MCV- Mean cell volume
* MCH- Mean corpuscular haemoglobin
* MCHC- Mean corpuscular haemoglobin concentration
* RDW- Red cell distribution width
measure the size, shape, and quality of your red blood
measured parameters on a haemotology analyser
Haemoglobin (Hb) (g/del)- Haemoglobin content tested by biochemical method
- Red blood cell count (RBC) (1012/L)
- Mean cell volume (MCV) femtoliters (fl)- Average size of RBC
calculated parameters on a haemotology analyser
Haematocrit (HCT)- Calculated from those measured (HCT = MCV x RBC)
* Some analysers measure HCT directly
Mean corpuscular haemoglobin (MCH) picograms (10-12 grams)
* Calculated: (MCH = Hb x10 / RBC)
Mean corpuscular haemoglobin concentration (MCHC)
* MCHC=Hb/HCT (Grams/Deciliter (g/dL)
RDW : Red Cell distribution width
* Reflect the range of variation of red blood cell (RBC) volume (MCV)
Indication about red cell mass (Anaemia or erythrocytosis)
Haemoglobin (HGB/Hb)
Packed cell volume (PCV)
Haematocrit (HCT)
Red blood cell count (RBC
Normocytic-
Erythrocytes of unremarkable size (MCV within normal range)
Microcytic (low MCV):
Breed specific (Japanese breeds)
Red cell haemoglobin concentration determines when division stops – iron
deficiency allows one more division: smaller red cells.
Other disease process which interfere with haemoglobin synthesis (vitamin B6
deficiency/Liver disease)
Macrocytic (high MCV)
Presence of immature RBCs (larger than mature
RBCs
* Breed specific, giant poodles,
* In some bone marrow disorders
* Vitamin/nutritional deficiencies (Vitamin B12)
* A common artefact in stored/old (usually
posted) blood samples (RBCs swell up
Normochromic/hypochromic
Nomenklatura which reflects variation in haemoglobin concentration
Reflected by MCHC / MCH values
- Normochromic
- Hypochromic (low MCHC/MCH):
- In iron deficiency/ poor iron incorporation (with
microcytosis) - Presence of immature RBCs (are not fully
haemoglobinised)
Hyperchromic (high MCHC/MCH):
* Not physiologically possible
* Always artefact (i.e. haemolysis), yet could be clinically
informative
measurements to help to classify anaemias
- Mild (>30), moderate (>20), <20 severe
- Normocytic, microcytic, macrocytic
- Normochromic, hypochromic (hyperchromic)
- Regenerative or non-regenerative
dot plots
e.g fluresense vs granularity (neuclear material vs complexity)
neutrophils- comact nuclei so dont florese massivly
esinophils- more complex than neutrophils
basophils- floresance high
monocytes- some complexity and lots of florecese
red cell run-
flourecence vs size
erythrocytes- vast majority have no nuclie and therefore no flurecence
polychromatophils- do florese, indicates rejenerative anemia
platlets- small flurecense and size
regenerative anemia
blood loss
haemolysis- IMHA, oxidative damage, microangioplastic anemia
non- regenerative anemia
mild- chronic disease
hypothyroidism
renal disease
underlying bone marrow disese
multifactoral
acute anemia ahead of regeneration
WBC morphological abnormalities
Neutrophils:
* Left-shift
* Toxicity
Lymphocytes:
* Reactive
* Atypical
Poikilocytosis
no analyser will provide this information
an increase in abnormal red blood cells of any shape that makes up 10% or more of the total population. Poikilocytes can be flat, elongated, teardrop-shaped, crescent-shaped, sickle-shaped, or can have pointy or thorn-like projections, or may have other abnormal features.
oxidative damage- centrocytes, spherocytes, keratocytes, heinz bodies
IMHA- aglutination, spherocytes, ghost cells
metabolic/ genetoc deifiencies-target cells, ovalecytes (refferal case)
fragmentation/ sheering damage- ecanthocytes, shistocytes, microspherocyts
When should you prepare and review a blood film
- Anaemic patients
- High WBC counts
- Low WBC/PLT counts
- Investigation of sick patients
- Flags in dot plot/indistinct segregation of clusters
Preparing a fresh blood film
Overt anaemia:
* Increase the angle
* Use more blood
* Make the smear shorter
Suspect erythrocytosis:
* Decrease the angle
* Use less blood
* Make the smear longee
Film examination: Platelet estimate
Rough estimate
Look at a number of fields
In the monolayer
>8-10 per HPF = normal
<2 per HPF = marked
thrombocytopenia
No clumping
* No clot
Manual PLT estimate:
* Count PLT in 10 100X fields
* Take the mean (/10)
* X 20
* = [PLT] x 109/L
Film examination:
1.Platelets
2.Erythrocytes
3.Leukocytes
* Initially scan at 10X
* Film quality
* Density
* Atypical features
* Go to higher power to confirm
features/assess morphology
* Go to 100X HPF for quantification in
the monolaye
Regeneration without anaemia
- Compensation
- Splenic contraction
- Chronic hypoxia
- Anaemia obscured by dehydration
- Breed appropriate Hct?
Assessment of regeneration in cats
- Cats are not small dogs!
- Reticulocytes = aggregate and punctate
- Punctate reticulocytes:
- In dogs are short-lived in circulation
- In cats, circulate >1 week- Not a good measure of acute regeneration But may be contributing to recovery
RBC morphology: Features of IMHA
Spherocytosis (Dogs)
- Ghost cells- Ideally on a fresh smear
- Questionable results?
- In-saline agglutination
- +/- Coomb’s test
- Regenerative vs Non-regenerative
Coombs test
Utilisation of antibodies
which target IgG, IgM and
complement to bridge between
erythrocytes coated with
antibodies and enhance
agglutination
igm gross aglutination is obvious
igg doesnt creat a lot of aglutination so coobs is good for this- also apears with spherocytes
Poikilocytes / shearing damage
Significance?
* >1/2 per 100X field?
* Associated anaemia?
* Polychromasia?
* Keratocytes in cats?
Common differentials:
* Vascular tumour
* Hepatic/splenic disease
* DIC
* ++
nterpretation of acanthocytosis
Acanthocytes (from the Greek word acantha, which means thorn), or spur cells, are spiculated red cells with a few projections of varying size and surface distribution
- Highly significant in dogs:
- Splenic neoplasia
- Commonly vascular tumours/ marked splenic
dysfunction, - Ddx: DIC, vasculitis, cardiovascular disease, iron def.,
Angiostronglyosis ++ - In cats:
- Less specific (mostly associated with liver
disease)
Morphological features of iron deficiency
- Microcytic, hypochromic
- +/- Codocytosis
- +/- Shear injury
Morphological features of oxidative insult
Heinz bodies-
Oxidative denaturation and precipitation of
globin by oxidation of Thiol (sulfhydryl) groups
Eccentrocytes-
Adhesion of opposing areas of the cytoplasmic
face of the erythrocyte membrane and the
formation of eccentrocytes
Pyknocytes-
* Develop from eccentrocytes following the loss of
fused membrane leaf; Pyknocytes are irregularly
spheroid with only a tag of fused membrane
remaining
Haemolytic anaemia due to oxidative damage
Ingestion of oxidative substances-
* Onion
* Garlic
* Moth ball
* Zinc
* Paracetamol
- Metabolic diseases
- Acid base disorders
Nucleated cells
- Low power:
- Do numbers agree with [WBC]?
- Is distribution even?
- High power:
- Does the spread agree with
WBC differential counts? - Are there morphological
abnormalities
Neutrophil morphology and left-shift
Neutrophils:
* Segmented nuclei
* Poorly staining granules
* Coarse chromatin
Bands
* Hypo segmented
* Fine chromatin
Left-shift = active inflammation
