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
Toxic neutrophils
Neutrophils: toxic change includes Morpholoical abnormalities
Could indicate:
* Acute infection
* Stimulation of neutrophil production
* Time for maturation is shortened
3 main causes of Neutrophilia
inflammation
corticosteroids, both exogenous and endogenous
endogenous epinephrine
3 main reasons for Lymphocytosis
- Non-specific inflammation response
- Viral infection
- Adrenaline
4 main reasons for Lymphopenia
- Common finding with viral infection
- Acute infection or inflammation
- Effect of corticosteroids
- Immunosuppression
Precursors to macrophages
Monocytes
2 causes of Monocytosis
- Inflammation
- Tissue necrosis
Monocytopenia in horses
- Clinically not significant
- Small amount also in healthy horses
Eosinophilia in horses (4)
- Rare, very slight changes
- Internal parasites
- Larvae migration in tissues
- Hypersensitivity
Eosinopenia in horses (3)
- Small amount also in healthy horses
- Common with stress leukogram
- Endogenous corticosteroids
Basophilia in horses (3)
- Very rare
- Mainly with eosinophilia
- hypersensitivity
Physiological leukocytosis
Due to Epinephrine (fight or flight reaction) but not the same as a stress leukogram.
* Spleenic contraction
* Neutrophilia (without left shift)
* Lymphocytosis
stress leukogram
due to Endogenous corticosteroids
- Neutrophilia (without left shift)
- Eosinopenia
- Lymphopenia
- Monocytosis
Thrombogram =
A thrombogram is a graphical representation or measurement of various parameters related to blood coagulation or clotting.
It provides information about the different stages of blood clot formation and can be used to assess the overall clotting profile of an individual.
Name 4 Liver biochem values
ALP, Alkaline phosphatase
AST, Aspartate Aminotransferase
bilirubiin and GGT
Name 2 biochem values that can tell you about muscle metabolism.
CK , Creatine Kinase
When muscle cells are damaged, CK is released into the bloodstream.
AST, aspartate aminotransferase
When muscle cells are damaged or injured, AST is released into the bloodstream, leading to elevated levels in blood tests.
Lactate
Increased levels of lactate in the blood may suggest that the muscles are relying on anaerobic metabolism for energy production.
Total protein =
albumin+ globulins
Albumin: negative acute phase protein
Hypoalbuminemia can be due to (2)
Losses (GIT, kidneys, body cavities)
Loss of production
* Inflammation, liver disease
* Starvation
Hyperalbuminemia frequently indicates
- Dehydration
everything that isn’t albumin is
globulins
Hyperglobulinemia can be due to
- Chronic diseases
- Neoplasia, Rare
Hypoglobulinemia can be due to (6)
- Hemorrhage, protein losing enteropathies,
exudative skin disorder - Infections
- Immunodeficiency
- Congenital
- Acquired: passive transfer disorder
- Tumors
Albumin and globulins ratio
should be 1
Alb:glob=1
Negative acute phase protein used in horses
albumin
Main 2 Positive acute phase proteins in horses
- Fibrinogen
- SAA- serum amyloid A
Fibrinogen in horses is measured from what sample
whole blood hematology, etda tube
SAA- serum amyloid A is measured from what sample
From serum or heparinizied plasma
* Red/green cap
Creatinine in Premature and newborn foals
have norm higher results (until 3 days)
When to measure kidney values?
- Colic
- Colitis: Especially when get NSAIDs without fluids!
- Foal: Neonatal nephropathy or prerenal/renal
- Weight loss, other chronic diseases
- Myositis
Creatine:urea ratio can tell you?
To test liver functionality (3)
Ammonia, urea, serum bile acids
Hepatocellular “leakage”, which values would you test to assess (3)
* Measures cell death to membrane leakage
* AST, SDH, GLDH
Measures cell death to membrane leakage
AST: aspartate aminotransferase
SDH: sorbitol dehydrogenase
GLDH: glutamate dehydrogenase
To assess Cholestasis, which values (2)
GGT, bilirubin
GGT: gamma glutamyl transferase is Specific to
hepatobiliary disease (epithelium of biliary ducts)
Small increase seen in the following cases:
* Foals
* Colic
* Corticosteroids
Bilirubin can be either
Conjugated (water soluble) and unconjugated form
- 80% in erythrolysis (unconjugated)
- Liver conjugates bilirubin
- Eliminates bilirubin with bile acids (conjugated)
Hyperbilirubinemia (unconjugated) can indicate? (3)
vs
Hyperbilirubinemia (conjugated)?
unconjugated:
* Hemolysis
* Starving
* Liver disease
Hyperbilirubinemia (conjugated)
* Biliary ducts obstruction
* Even in that case horses still have ca 50% unconjugated bilirubin
physiological icterus possible in horses!
Most common liver leakage value
AST: aspartate aminotransferase but is not actually liver specific!
Can be found:
* Skeletal muscles, liver, heart muscles, erythrocytes, kidney epithelium
- Could be normal with chronic diseases
- Compare with CK, look for hemolysis!
Increases also:
* Young horse in training: ca 2x rise
SDH is specific for?
the liver
- Increases with primary and aslo secondary liver disease
- Hepatocellular
- Starts to increase ca 24h after injury
- Not stable enzyme. -5h in room temperture, +4⁰C 24h - analyze fast!
GLDH – glutamate dehydrogenase is Similar to SDH, but more stable
* In young foal a bit higher
Constant hyperglycemia in a very sick horse is a
negative prognostic indicator
Measure with insulin.
Hypoglycemia on the other hand is rare in adult horses since they have good gluconeogenesis.
Hyperglycemia in horses
- Sign of insuline resistance
- Physiologicak: pregnancy, stress
- Sepsis (inflammation mediator)
- Drugs: corticosteroids
- Metabolic syndrome
- Iatrogenic: Glucose infusion
Hypoglycemia in horses
- Starvation, malabsorption
- Exhausted horse (endurance)
- Tumors
- Sepsis
- Liver failure
- Important in foals!
Hyperchloremia can be due to (3)
- Kidney failure, tubular acidosis
- Chronic respiratory alkalosis
- Diuretics
