Week 2-5 Flashcards
CBC
Comprised of:
Packed cell volume (PCV)
Plasma protein concentration (TP)
Blood Smear
-WBC differential and morphology
- Platelet clumping, morphology and estimate
- RBC arrangement and morphology
- Occasionally a reticulocyte count
PCV
Aka Hct
Percentage of total blood volume composed of RBCs
% and L/L
What is always in the buffy coat
WBC and platelet
What is sometimes there?
nRBC + heartworm microfilia
Plasma Protein units
g/dL
What are blood smears used for?
Performing a platelet count
Performing a differential WBC count
Evaluating the morphology of RBCs, WBCs and platelets (including looking for the presence of blood parasites)
Which tube is used for blood smears?
Purple top
Why should we make blood smears immediately?
Morphological changes will occur due to the EDTA
Size of drop?
3mm
Angle of spreader slide?
30 degrees
How much should the blood spread across the slide?
2/3
How to know if the blood smear was stained properly?
Even purple colour when viewing grossly
RBCs appear a pinkish colour
Platelets are purple
WBCs are properly coloured
Reticulocyte count
Not routine to complete with all CBCs
Immature RBCs formed where?
bone marrow
Are Immature vs mature RBCs bigger?
Immature
Immature RBCs N:C ratio
N < C
Chromatin
delicate, fine and reticulate (meshed network)
Immature RBCs nucleoli
found in nucleus and vary in size and number
Nuclear chromatin
composed of DNA and stains light purple
Cytoplasm
contains large amounts of RNA that stain blue
has tubular assembly of a golgi apparatus which shows as a light zone around the nucleus
Mature RBC size
Gets smaller as they mature
RBC nuclei and chromatin
gets smaller and chromatin becomes coarse, clumped and compact - becomes more blue
RBC cytoplasm
Gets more red
RBC lifespan
Canine 100-120 days
Feline 70-80 days
RBC
aka erythrocyte
RBC functions
▪ Transports and protects hemoglobin (which
carries oxygen to tissues)
▪ Homeostasis – water and electrolytes
▪ Antibody protection
▪ Temperature regulation
▪ Buffering system
▪ Hemostasis
Canine RBC
7.0 microns
Biconcave disc with central pallor
Feline/Equine/Bovine RBC
5.8 microns
Biconcave disc with no central pallor (due to small size)
Sheep RBC
4.5 microns
Biconcave disc with no central pallor
Goat RBC
3.2 microns
Biconcave disc with no cental pallor
Each species’ RBC size from largest to smallest
Canine -> Feline/Equine/Bovine -> Sheep -> Goat
6 RBC maturation stages
Rubriblast
Prorubricyte
Rubricyte
Metarubricyte
Polychromatic RBC
Erythrocyte
Rubriblast
Large, perfectly round cell with large, round nucleus and royal blue cytoplasm
Light blue nucleoli
Nuclear chromatin is stippled
Perinuclear clear area
Prorubricyte
Similar to rubriblast but smaller
No nucleoli present
Round nucleus
Chromatin more coarse (hard to tell)
Royal blue cytoplasm
Perinuclear clear zone
Rubricyte
Nuclear chromatin (spoked wheel pattern)
Nucleus is round and dark purple with blue black chromatin
Cytoplasm dark blue; lightens to pink as hemoglobin increases
Divided into basophilic, polychromatic or normochromatic as presence of hemoglobin increases
Metarubricyte
Nucleus undergoes a pyknotic degeneration (shrinking, dense)
Appears as dark blue mass with no distinct chromatin structure
Cytoplasm is pink (due to hemoglobin) with a basophilic hue
When seen in peripheral blood they are called nucleated RBCs
Polychromatophilic Erythrocyte
Anucleate erythrocyte with slight basophilia
Larger than mature RBCs
When stained with new methylene blue, some show a network of blue fibers
- RNA
- Cells are called reticulocytes
Erythrocyte
Mature RBC in peripheral blood
Stain pink
Rouleaux
Stacked like coins
Agglutination
Clumping
Anisocytosis
No uniform size
Macrocytosis
Larger size
Normocytosis
Normal sized RBCs
Microcytosis
Smaller than usual
Hypochromasia
Decreased staining caused by reduced hemoglobin
Most often are microcytes
Decreased MCV (mean corpuscle value)
Hyperchromasia
Does not exist because each RBC has a limit of hemoglobin it can carry
Polychromasia
Polychromatophilic RBC
These are reticulocytes when stained with new methylene blue
Poikilocytes
General term describing abnormally shaped RBCs
Schizocytes
RBC fragments
Torn RBC
Why are there schizocytes?
Formed by intravascular trauma and mechanical injury which resulting in turbulent blood flow
Acanthocytes
Irregular blunt projection cells
Few, unevenly distributed projections
Variable length and diameter
Why are there acanthocytes?
Due to alternations in lipid composition of the RBCs
Seen in hepatic diseases
From cholesterol changes at cell membrane
Seen in hemangiosarcoma (acanthocytes considered a blood biomarker for this condition)
Echinocytes
Numerous short, evenly spaced blunt to sharp projections of uniform shape and size
Why are there echinocytes?
Can be due to renal disease or an electrolyte imbalance but often due to faulty technique
- Crenation caused by slow smear drying
- Excessive anticoagulant may also cause
Spherocytes
Darkly stained cells with reduced or no central pallor
Perfectly round sphere, no longer disk shaped
Not easily detected in species other than dogs because other species lack central pallor
Typically, the volume of cell is normal
Normal MCV
Why are there spherocytes?
Seen in IMHA - macrophage bites the RBC
Leptocytes
General term referring to cells with increased membrane surface relative to cell volume
- Can result to cell folding
Cells take on a variety of shapes
Includes target cells and stomatocytes
Target cells
aka Codocyte
Type of leptocyte
Bullseye appearance
Central rounded area of Hb surrounded by a clear zone with a dense ring of Hb at the periphery
Why are target cells found?
Found in hepatic disorders, iron deficiency and IMHA
Stomatocyte
Type of leptocyte
Cup shaped RBC with an oval, elongated mouth appearing in the central pallor
Artifact due to thick blood smear
Why are there stomatocytes?
Non-specific finding seen in:
- Hereditary condition in malamutes
- Drug-induced
- Regenerative anemia
- Liver disease
- Lead poisoning
Blister cell or pre-keratocyte
Blister on one side of RBC forming an area devoid of hemoglobin
Why are there blister cells?
Oxidative injury seen with iron deficiency
Keratocyte
Ruptured blister with two upright “cattle horn-like” projections
Projections fragment from RBC to form schizocytes
Why are there keratocytes?
Can be seen in healthy cats with no clear significance
Can be seen in DIC, hemangiosarcoma, iron deficiency anemia, liver disease
Dacryocyte
Tear drop shaped erythrocyte with a single elongated or pointed end
Why are there decryocytes?
May be found in bone marrow disorders of dogs and cats, iron deficiency in ruminants, kidney and splenic disorders in dogs
Result of mechanical fragmentation
Drepanocyte
Sickle cell
RBC changes to a spindle shape
- Cell elongates and comes to a sharp or round point on both ends
Why are there drepanocytes?
Result of alteration of hemoglobin due to temperature, oxygen and pH changes (alkalosis)
Seen in normal deer, angora goat and some sheep blood
Eccentrocyte
Red at one end and clear at the other end giving a half moon appearance
Why are there eccentrocytes?
Due to excess oxidant stress
Found in hemolytic diseases seen in dogs with onion/acetaminophen ingestion
Often see heinz bodies with them
Elliptocyte
Ovalocyte (previous name)
Oval or elliptical RBC
More flat than concave
Why are there elliptocytes?
Can be non-specific or due to smear making technique
May be seen in iron deficiency anemia or liver disease
Ghost cells
Extremely pale to colourless
Appearing round to smudge-like
Devoid of hemoglobin in the cytoplasmW
Why are there ghost cells?
Can be due to intravascular hemolysis or blood film preparation
Torocyte
Punched out cell
Abrupt change from dense red to white area giving a “punched out” apprearance
Why do we see torocytes?
Artifact of improper spreading of blood on slide
Basophilic
