Evaluating a blood smear Flashcards
When performing a smear on anemic blood you should _ the angle
increase
When performing a smear on dehydrated blood, you should _ the angle
decrease
What is the function of an erythrocyte
oxygen and carbon dioxide transport
What carries most of the oxygen
hemoglobin
When is Hgb production completed?
when RBC becomes fully mature
Where is hemoglobin located
in RBCs
What stimulates RBC production
hypoxia
How does hypoxia stimulate RBC production?
causes increased release of a hormone, erythropoietin (EPO) from kidney
How does EPO cause RBC production
EPO stimulates the stem cells (pleuripotential) cells of the bone marrow to become RBC precursors
What phase of RBC maturation is described:
-smaller, basophilic cytoplasm, nucleus is pyknotic, chromatin condensed
Metarubricyte
What phase of RBC maturation is described:
-smaller, cytoplasm many colors (blue-pink), NO NUCLEUS
polychromatophil
What phase of RBC maturation is described:
-Smallest, pink cytoplasm, no nucleus
Mature RBC
Trends of RBC maturation:
Size: large to small
Nucleus: present & large to absent
Cytoplasm: blue to pink
Organelles: ribosomes to none
What is the last cell to be nucleated
metarubricyte
Which cell is un-nucleated and basophilic
Polychromatophil
The following are the 3 effects of _:
-Stimulates pleuripotential cell to differentiate into rubriblast
-increases hemoglobin production
-causes early release of polychromatophils
EPO
What does it mean if you see polychromatophils on a smear
the bone marrow is kicking them out too early meaning there is a demand for them to help carry O2 (even though they can’t carry the full amount)
Why won’t polychromatophils be in circulation immediately even with sudden blood loss?
it takes 5-7 days for formation/maturation
RBCs don’t deal well with _ substances
toxic
What is the life span of a RBC
3 months (90 days)
Where do dead/dying/destructed RBCs go?
the spleen
What occurs in the primary way of RBC removal
Extravascular hemolysis
Fixed macrophages are located in what organs
spleen, liver, bone marrow
In MPS, as a RBC ages it loses flexibility so can’t “percolate” becomes trapped in the _ of the spleen, liver, and bone marrow
sinusoids (spaces)
What occurs in the secondary way of RBC removal
Intravascular hemolysis
If there is excessive IVH excess Hgb is excreted in urine, this is called
hemoglobinuria
MCV is used to determine _ of RBC
size (volume)
MCHC and MCH is used to indicate
amount of Hgb in RBC, so color
Normal values for MCV in dogs and cats
Dog: 60-70fl
Cat: 38-55fl
Terms to describe MCV:
-Less than normal size = _
microcytic
Terms to describe MCV:
-normal size range
normocytic
Terms to describe MCV:
-Greater than normal size
Macrocytic
Interpreation of microcytic MCV
Fe deficiency, normal in Akitas
Interpretation of normocytic MCV
mature RBCs, brand new anemia
Interpretation of macrocytic MCV
responding (regenerative) anemia..WHY? congenital in some mini and toy poodles
Normal range for MCHC in dogs and cats
30-36 g/dl
Term for less Hgb than normal in MCHC
hypochromic
Term for normal Hgb amount in MCHC
normochromic
Cells that stain more intensely are called hyper chromic but why do we term this polychromasia?
because true increase in Hgb doesn’t happen
Interpretation of Hypochromic MCHC
Fe deficiency
Interpretation of normochromic MCHC
normal, brand new anemia, chronic anemia
Interpretation of polychromasia MCHC
presence of erythrocytes w/ faint blue cytoplasm, typically macrocytic
Reticulocyte count evaluates what
the bone marrow’s response in anemia
Reticulocyte definition
polychromatophil when stained with new methylene blue (NMB)
Why don’t we do a retic count in horses
because they don’t release polychromatic cells into circulation
Cats and birds always have some retics in circulation even without _
anemia
Dogs don’t have retics in circulation without _
anemia
How to perform a reticulocyte count
-Mix equal amounts of EDTA whole blood w/ NMB stain in a test tube
-Let sit 10-20 min. at room temp
-Place drop of mixture on clean slide; smear like blood film and allow to air dry
What retics should you count for cats and birds
ONLY aggregate retics
In _ you should count both type retics you see
dogs
Observed reticulocyte count calculation
1000RBC x 0.1
Ex: saw 27 retics when counted 1000 RBC
27 x 0.1= 2.7%
Absolute reticulocyte count calculation
reticulocyte % (#/100) x RBC count x 1000
Corrected reticulocyte count calculation
Observed retic ct x patient PCV/ mean PCV for species
Ex: 2.7% x 20/45= 1.19= 1.2%
What should be evaluated of RBCs
- Cell arrangements/ associations
- Color
- Size
4.Shape - Inclusions
Size of RBC terms
Anisocytosis
Microcytosis
Macrocytosis
Color of RBC terms
Polychromasia
Hypochromasia
Normochromasia
Abnormal Shape term for RBC
poikilocytosis
RBC associations
Rouleaux and Agglutination
Which is the reversible association condition
Rouleaux
Where should associations be examined
monolayer junction
What is the rouleaux association caused by
sticky RBCs; ex. high protein levels in plasma make sticky
see with inflammation; seen in healthy horses and cats
Which RBC association condition is irreversible
agglutination
What is agglutination caused by
Ag:Ab interaction (cross link bonding)
occurs with immune disorders ex: AIHA; blood transfusion reaction
What test should be done if you can’t tell if the association is rouleaux or agglutination
saline wash testing; agglutination will remain, rouleaux will disappear
- random fields in monolayer should be observed for individual RBC morphology
5-10
What is the term used when RBCs are unequal in size in 3-4 random fields
anisocytosis then qualify: slight, mild, moderate, marked or +1 etc.
Anisocytosis is normal in
young animals; adult ruminants
Anisocystosis is seen in _ _ due to immature RBCs; when 2 cell populations are present (blood transfusions)
regenerative anemia
How to verify RBCs are smaller in size (microcytic)
MCV is low
How to verify RBCs are larger (macrocytic)
MCV is high
How to verify RBCs are normal in color
MCHC is normal (normochromic)
How to verify RBCs are more pale
low MCHC (hypochromic)
If some RBCs are bluish in color what is the comment on morphology
polychromasia
RBCs in a deeper red color are
spherocytes
Any abnormal RBC shape is termed
poikilocytosis
What is the spur cell called
acanthocyte
What is the target cell called
codocyte
What is the tear drop cell called
Dacrocyte
What is the biconcave disk called
Discocyte
What is the sickle cell called
Drepanocyte
What is the crenated cell, burr cell called
Echinocyte
What is the ovalocyte called
Elliptocyte
What is the helmet cell called
Keratocyte
What is the thin cell called
leptocyte
What is the mouth cell called
stomatocyte
characteristics of an acanthocyte
-has irregularly placed, variable sized spicules
-not as many spikes as echinocyte
Acanthocytes are seen with
liver disease, splenic disease, fragmentation disorders (like hemangiosarcoma)
Codocytes are caused by
too much membrane or reduced Hgb content
Polychromatophils commonly _
leptocytes
Codocytes are seen in
regenerative anemia (in polychromatophils), liver or splenic disease (in normochomric cells), iron deficiency anemia (in hypochromic cells)
Dacrocytes are seen with
fragmentation disease (microangiopathic disease)
Caution with looking for echinocytes
looks like inclusions and on side look like burr cell
When are echinocytes seen
RBCs dehydrated, pH increased, hypophosphatemia, uremia, dogs w/ rattlesnake envenomation, pyruvate kinase deficiency, horses with total cation depletion
When are echinocytes seen as artifact
excess EDTA, improper mixing, old blood, smear prep
When disease are elliptocytes seen with
cats w/ bone marrow abnormalities, hepatic lipidosis, portosystemic shunts, hereditary
What species are elliptocytes normal in
camelid, avnin, reptile, fish
Keratocytes are seen with
fragmentation hemolysis (ex. Heinz body hemolytic anemia, liver disease)
Schisctocyte or shizocyte are seen with
DIC, vasculitis, fragmentation hemolysis, iron deficiency anemia
Torocytes are seen with
low Hgb
Inclusions can be
Developmental, Toxic, Infectious
Inclusions can be _ or _ the RBC
in or on
Developmental inclusions
Howell-Jolly bodies
Basophillic stippling
Developmental inclusions are normal in what breeds
mini schnauzers and dachshunds (in low numbers)
Developmental inclusions are seen with what diseases
regenerative anemia, lead poisoning, hematopoietic neoplasia, splenic tumors, hyperadrenocorticism
Characteristics of Howell-Jolly bodies
-nuclear remnants; always spherical, little dot in RBC
-present in small numbers in healthy cats & horses
-see with regenerative anemia, following splenectomy
Characteristics of Basophilic stippling
-looks like a retic (but is not) and is on routine stain smear
-see with regenerative anemia in ruminants
-in dog & human- lead poisoning
Toxic inclusions
Heinz bodies
Heinz bodies are seen with what toxicities
Acetominophen in cats; onions in dogs; maple leaf in horse; zinc in all
Heinz bodies are composed of
denatured (oxidized) Hgb
All the following are _ inclusions:
-Anaplsmosis marginale
-Hemobartonella canis and felis
-Cytauxzoon sp.
-Babesia sp.
-Distemper
-Trypanosoma sp.
-Ehrlichia
Infectious
Anaplasmosis marginale produces
severe extravascular, hemolytic anemia
Anaplasmosis marginale is _ transmitted
tick
Mycoplasma canis and feels are transmitted by _ or infected blood
arthropods (ticks)
Hemobartonella Canis occurs in
long chains in puppies or splenectomized dogs
Hemobartonella Canis=Mycoplasma haemocanis occurs in
chains, single cocci, ring forms in immunosuppressed cats ( FeLV or FIV positive)
Hemobartonella felis= Mycoplasma haemofelis may cause
fatal anemia
Cytauxzoon sp. is tick transmitted and occurs in
central & SE US (bobcat is host)
Babes sp. is tick transmitted and causes
intravascular hemolysis
Distemper inclusions can be found on
RBCs, WBCs, epithelial cells
trypanosoma sp. occurs in tropical climates in
cattle, sheep, goats, camel, antelope, birds, man
Ehrlichia sp. is tick transmitted and is NOT RBC parasite; is found in
WBCs or platelets
What should be used to find ehrlichia sp. organisms
buffy coat to concentrate and find organisms
