What conditions may altered erythrocyte numbers show?
^ = erthyrocytosis v = aneamia
When may leukocytes be analysed/what can they show?
Inflammatory conditions Neoplastic conditions Chemotherapy (check for leukopenia)
What can platelets show?
Bleeding disorders DIC (Disseminated Intravascular Coagulopathy)
How is plasma assessed?
Colour - should be clear/straw - if pink = heamolysis - if yellow = icterus
What two aspects of blood cells are assessed?
Number (often by machine) Morphology in blood smears (should still be checked if only briefly to confirm machine findings)
What can PCV show?
Aneamia/Dehydration Buffy coat assessmnet Plasma colour Total protein measurement from plasma once layers have been measured [check these values against machine]
What form of RBCs may be released into the circulation if the BM is struggling to keep up with the demand for cells?
Reticulocytes/polychromatophils Still un-nucleated (pre-cursor to these has nucleus and is rarely released into bloodstream)
What is RBCC?
Red blood cell concentration
What is HGB?
Total heamoglobin - if RBCs are being lysed this Hgb is released and value ^ (?)
What is HCT?
Heamatocrit Equivalent to spun PCV but calculated differently - machine calculates by measuring size and number of RBCs.
What is MCV?
Mean Cell Volume Will be increased if blood cells are being produced at a rapid rate and immature cells released into circulation. Will be decreased if Hbg is low/being lost
What is MCH?
Mean Cell Heamoglobin Hbg per cell
What is MCHC?
Mean Cell Heamoglobin CONCENTRATION Amount of Hbg per unit VOLUME of blood - dependent on size of cell (larger cells will require more Hbg for same concentration per unit volume) This is associated with RBC maturation - will keep dividing until have sufficient Hbg concentration
What is RDW?
Redcell Distribution Width Shows uniformity/variability of cell sizes Will be greater if ^ demand for cells is meaning immature cells are released into the circulation
How is ameamia classified (3 stages) ?
1. Mild / Moderate / Severe [different differentials] 2. MCV - Normocytic / Microcytic / Macrocytic 3. MCHC - Normochromic / Hypochromic [Hyperchromia does not exist as a pathology as RBCs are released when sufficient Hbg has been added. Thus only an artifact of RBC lysing etc.]
What is the ultimate Q we try to answer when investigating aneamia?
Regenerative or non regenerative?
When are normocytic cells seen associated with aneamia? What will be noted about normocytic cells in anemic animals?
Mild, NON-regenerative - acute heamorrhage etc > will be ^ spacing between cells
When are microcytic cells seen?
Iron deficiency, PSS, Hepatic failure, AKITAS [congenital breed difference] - MCHC determines when division of immature RBCs stops - Fe deficiency allows more division -> smaller cells to maintain same concentration
When are macrocytic cells seen?
Regeneration - immature RBCs have not condensed, released as polychromatophils POODLES [congenital breed predisposition - still pathological]
When are hypochromic cells sen?
v Hbg concentration due to Fe deficiency or poor Fe incorporation (with microcytosis) Associated with MCHC/MCH on blood panel
Why may RBCs appear see through or just have an outline?
v thickness / v volume (not necessarily v diameter)
What are the 2 differentials for regenerative anaemia?
Heamolysis (eg. immune mediated) Heamorrhage
What are the most common differentials for non-regenerative?
Anaemia of chronic/inflammatory disease (mild) Chronic renal failure (severe) Decreased production in BM If acute stages of anaemia will appear non-regenerative as marrow still catching up
How can regenerative anaemia be distinguished?
^ no reticulocytes
How do reticulocytes and polychromatophils differ?
They are the same cell when prepared in different ways. IDed due to the cell still containing "machinery" that enables them to make Hbg. Should lose this before being released as fully mature cells. - Polychromatophil = Diff-Quick/Giemsa stain, immature cells show as LARGER and BLUER cells. - Reticulocytes = New Methylene Blue stain, which causes RNA to precipitate and form aggregates/reticulum.
Do polycromatophils continue to mature once released into the blood stream?
Which species have different reticulocytes? How do they differ? How does this affect analysis?
Cats Cat retics released as "aggregate retics" then mature to "punctate retics" over time When counting retics only these populations separately and not lumped together. If only one is counted this should be aggregate.
How is reticulocyte % calculated?
1000 red cells counted, retics expressed as a percentage Must be CORRECTED for PCV of the patient Retic % x patient's PCV/normal PCV (Otherwise same no. reticulocytes will give greater % in an anaemic animal)
What is the normal reticulocyte % in healthy dog/cats?
~45% dog ~35% cat
What difference in reticulocyte % is clinically significant?
>1% dogs >0.4% cats
What form of reticulocyte measurment may be better than corrected %? What is the rough range of values for this measurement?
Absolute reticulocyte concentration - [RBC] x retic % - can only be carried out by machine >60-80,000/microL = regenerative *correction NOT neccesary as absolute conc calculated*
Give some signs of regeneration visable on a blood smear
Polychromasia Anisocytosis (different shapes and sizes) Macrocytosis nRBCs (nucleated) Howell-Joly bodies (remnant of nucleus) Codocytosis Basophilic stippling (purple/blue dots in cell)
What differences in RBC morphology may be noted?
Spherocytes, ghost cells Hypochromasia/leptocytosis [Fe deficiency] Shear products - spiky! (keratocytes, schistocytes, acanthocytes) Oxidative damage (Heinz bodies, eccentrocytes, pyknocytes) Organisms (Babesia)
What does CBC stand for?
Complete blood count
How are leukocytes analysed on a blood smear?
Count 100 cells, mark no. of leukocytes Expressed as %
How may neutrophil morphology show pathologies?
Left shift (band neutrophils) show acute infection Toxicity (intra celluluar granules "Dohle bodies" present) show inflammation, or may be normal if in small numbers.
In which species are toxic neutrophils more abundant?
Horses and cats
What is the average lifespan of a RBC?
Which neutrophil pool does a blood sample represent? How may this be affected?
Circulating neutrophil pool Many will be adhered to vessel wall - if stressed, ^BP frees many of these.
Where may neutrophils be stored to v cNP?
Enter tissues or adhere to vessel walls
What are the 3 main questions to be asked regarding neutrophil levels?
1. How much is leaving -> tissues? 2. How much is coming from Marrow? 3. How much is adhered to walls?
What are the two forms of left shift classification?
Regenerative left shift - Neutrophilia - More segmented than band neutrophils Degenerative left shift - Neutropenia - More bands than segmented > can be in between the two.
What are the common changes in various leukocyte parameters associated with different diseases referred to as?
What are the forms of leukaemia?
- Acute (quick death) v chronic (slow progression)
- Lymphoid (lymphocytes) v myeloid (neutrophils) All involve circulation of neoplastic cells
- ALL/AML/CLL/CML abbreviations
What may be seen in acute leukaemias? How can lymphoid be differentiated from myeloid?
Many blast cells - difficult to identify cells of origin but MORE likely to be lymphoid.
- ALL v stage 5 lymphoma? [not sure what this means, maybe hard to differentiate the 2 diseases?]
- If signs of segmentation are seen then = myloid/myelomonocytic
What may be seen in chronic leukaemia?
Normal looking cells, just ^ numbers
- CLL: lymphoid cells are small and mature
- CML: neutrophils appear normal
What is a common problem associated with measuring platelet numbers?
Clumping due to initiation of an inflammatory response v platelet count and abnormal distribution of cells within the sample