Equine diagnostics: Sampling blood Flashcards
Serum tubes contain…?
Either gel and/or coagulation activator
What is the GREY top tube used for?
Grey-top tube (potassium oxalate/sodium fluoride)
This tube contains potassium oxalate as an anticoagulant and sodium fluoride as a preservative – used to preserve glucose in whole blood and for some special chemistry tests.
Why is sodium citrate used for coagulation?
Citrate chelates free calcium ions preventing them from forming a complex with tissue factor and coagulation factor VIIa to promote the activation of coagulation factor X. This inhibits the extrinsic initiation of the coagulation cascade.
Where to obtain blood sample in horses? (5)
- Jugular vein (v. jugularis)
- Transverse facial vein sinus
- Cephalic vein (v. cephalica) not in adults
- Saphenous vein (v. saphena) not in adults
- Lateral thoracic vein
Diff between plasma and serum.
Plasma includes coagulation factors.
Error sources: why can RBCs shrink after drawing?
Not enough blood drawn into the EDTA tube can cause RBC crenation due to EDTA being hypertonic.
Döhle bodies are
light blue-gray, oval, basophilic, leukocyte inclusions located in the peripheral cytoplasm of neutrophils.
The presence of Döhle bodies in mature and immature neutrophils on a blood smear can be normal if they are present only in small numbers. They are also normally more abundant in cats and horses.
If there are many neutrophils in the bloodstream containing Döhle bodies, these can be referred to as toxic neutrophils.
If you need to draw blood frequently to e.g. check GLU often. How would you do it?
You can draw via the IV catheter but discard a minimum of 3 ml of blood by aspiration and only then draw your sample so as not to dilute your sample with IV fluids etc.
MCH & MCHC difference
Hemoglobin amount per red blood cell (MCH).
The amount of hemoglobin relative to the size of the cell (hemoglobin concentration) per red blood cell (MCHC).
Relative Erythrocytosis/polycytemia indicates
Dehydration
* Hemoconcentration
or
Splenic contraction
* Stress
* Training
Absolute Erythrocytosis/polycytemia indicates
is rare
Primary
* Production increases in bone marrow
* Response to hypoxia
* Tumors
Regenerative anemia indicates
Hemorrhage
* External
* Internal
or
Hemolysis
* Infection
* Toxicosis
* Immune-mediated
Non-regenerative anemia indicates
Decreased production
* Bone marrow supression
* Inflammation
* Chronic diseases
* Iron-deficiencyx
Macrocytosis of RBCs may be seen in (2)
anemias
normal in neonatal foals
Microcytosis of RBCs may be seen in what situations (2)
Too much EDTA
* Common artefact
Microcytosis may be seen in Foals up to 1 year of age due to iron deficiency anemia.
RDW
red cell distribution width
Variation in red blood cell volume within the red cell population
A Decrease in RDW is
not clinically important.
Reticulocytes in horses
Horses do not have reticulocytes!
Since Horses do not have reticulocytes, how is anemia assessed?
In horses, the bone marrow response to anemia is often assessed by evaluating other parameters such as the presence of polychromasia (immature red blood cells) on a blood smear.
Additionally, measuring serum erythropoietin levels and assessing the overall clinical picture are important aspects of evaluating anemia in horses.
Increase in Hgb could indicate
- Dehydration
- Spleen contraction (epinephrine)
Decrease in Hgb could indicate
- Fluid overload (over-dilution with fluids)
- Spleenic relaxation (anesthetics, sedation
- Anemia
HCT/PCV increase could indicate (2)
- Dehydration
- Spleen contraction (epinephrine)
HCT/PCV decrease could indicate (3)
- Fluid overload (over-dilution with fluids)
- Spleen relaxation (anesthetics, sedation
- Anemia
Monocyte
lymphocyte pic to show you the diff.
Neutrophil types (2)
- Band neutrophils (immature)
- Segmented neutrophils (mature)
circulate for 10-15h then move to tissues and body cavities
Left shift
Neutrophils: more Immature than mature
Indicates Inflammation