Clinical Pathology –
Color of Tube Anticoagulant Mechanism of Best for…
Action
Red None N/A Serum
chemistry,
protein
electrophoresis,
culture
Purple EDTA – Weak Chelates CBC, fluid -Underfillin
preservative calcium and cytology, blood g an EDTA
EDTA is other divalent smear, flow tube will
preferred for cations – cytometry, shrink the
most species strongly Coomb’s test cells
EXCEPT for
some retiles
and birds
Green Heparin Enhances Plasma
actions of chemistry, STAT
thrombin chemistry
Blood Gas
Blue Calcium Citrate Binds to Coagulation
Calcium Tests
Species Veins Needle size
Dogs Jugular, cephalic, lateral 21-22 gauge
saphenous
Cats Jugular, cephalic, medial 21-22 gauge
saphenous
Cattle Jugular, coccygeal 18-20 gauge
Horses Jugular, transverse facial 18-20 gauge
, sinus
CBC:
- Automated instrument report
- Manual count with hemocytometer – reptiles, amphibians, and birds
- Packed cell volume
- Blood smear evaluation
- Plasma color evaluation
Indices Assessing RBCs on CBC:
- Mass: HCT, PCV, RBC count, Hgb
o PCV – “spun hematocrit”. Percentage of blood volume comprised of
RBCs. A measure of blood carrying capacity. Measured by
centrifugation of blood sample in a hematocrit tube.
o HCT: Percentage of blood volume comprised of RBCs. Essentially the
same as the PCV but is a calculated value. (MCVxRBC/10)
- Characteristics: MCV, MCH, MCHC, RDW
- Regeneration: Reticulocytes %, Reticulocyte, abs
- Blood Smear Evaluation
Instruments for CBC:
- Hemocytometer: provides manual cell count, more labor intensive and less
accurate compared to automated instruments
- Impedance Method: electrical current across aperture. Cells move “single
file” past aperture, altering impedance, leading to voltage pulse. The
number of pulses is the number of cells. Amplitude corresponds to cell
volume.
- Laser Light Scatter: Cells pass through laser “single file”, light scatters at
different angles, instrument detects. Provides cell number, cell volume, and
cell complexity.
- Benchtop machines
Clinical Chemistry:
- Liver: ALT, ALP, AST, GGT, total protein, albumin, bilirubin, cholesterol,
glucose, BUN
- Kidneys: BUN, creatinine, electrolytes
- Muscle: CK, AST
- Proteins: Total proteins, albumin, globulin
- Minerals: calcium, magnesium, phosphorus
- Electrolytes: Sodium, potassium, chloride, ALP
- Endocrine: Glucose, sodium, potassium, ALP
- Acid-Base Balance: Anion gap, chloride, bicarbonate
, Serum: Harvest generally more than compared to plasma. Allow time to clot and
retract prior to centrifugation. Can take at least 30 minutes to maximize the
amount of serum.
Plasma: Can centrifuge immediately, no need to wait for a clot to form and retract.
This is preferred for emergent samples.
Hemostasis Test:
Sample handling depends on the specific test.
- Primary Stage: Platelet count and Platelet Estimate, Buccal Mucosal
Bleeding Time, Von-Willebrand Factor assays, Platelet Function Tests
- Secondary Stage: Pro-thrombin Time, Partial thromboplastin time, Activated
coagulation time, Fibrinogen, specific coagulation factor assays.
- Tertiary Stage: Fibrinogen degradation products, and D-dimers
Blood Smear:
Parts of a Smear – Feathered edge, monolayers, and body
Looks at:
- Morphology of RBCs, WBCs, or platelets
o Abnormal Shapes – poikilocytes
o Size – macrocytes, microcytes, anisocytosis (variation in size)
o Color – Hypochromasia, polychromasia
o Inclusions:
Siderocytes, basophilic stippling, Howell-Jolly, Heinz bodies
o Patterns:
Agglutination: RBCs are grouped like grape clusters.
Can artifactually increase the MCV
Occurs when Ab from one RBCs usually IgM
Presence is supportive of immune-mediated hemolysis
Color of Tube Anticoagulant Mechanism of Best for…
Action
Red None N/A Serum
chemistry,
protein
electrophoresis,
culture
Purple EDTA – Weak Chelates CBC, fluid -Underfillin
preservative calcium and cytology, blood g an EDTA
EDTA is other divalent smear, flow tube will
preferred for cations – cytometry, shrink the
most species strongly Coomb’s test cells
EXCEPT for
some retiles
and birds
Green Heparin Enhances Plasma
actions of chemistry, STAT
thrombin chemistry
Blood Gas
Blue Calcium Citrate Binds to Coagulation
Calcium Tests
Species Veins Needle size
Dogs Jugular, cephalic, lateral 21-22 gauge
saphenous
Cats Jugular, cephalic, medial 21-22 gauge
saphenous
Cattle Jugular, coccygeal 18-20 gauge
Horses Jugular, transverse facial 18-20 gauge
, sinus
CBC:
- Automated instrument report
- Manual count with hemocytometer – reptiles, amphibians, and birds
- Packed cell volume
- Blood smear evaluation
- Plasma color evaluation
Indices Assessing RBCs on CBC:
- Mass: HCT, PCV, RBC count, Hgb
o PCV – “spun hematocrit”. Percentage of blood volume comprised of
RBCs. A measure of blood carrying capacity. Measured by
centrifugation of blood sample in a hematocrit tube.
o HCT: Percentage of blood volume comprised of RBCs. Essentially the
same as the PCV but is a calculated value. (MCVxRBC/10)
- Characteristics: MCV, MCH, MCHC, RDW
- Regeneration: Reticulocytes %, Reticulocyte, abs
- Blood Smear Evaluation
Instruments for CBC:
- Hemocytometer: provides manual cell count, more labor intensive and less
accurate compared to automated instruments
- Impedance Method: electrical current across aperture. Cells move “single
file” past aperture, altering impedance, leading to voltage pulse. The
number of pulses is the number of cells. Amplitude corresponds to cell
volume.
- Laser Light Scatter: Cells pass through laser “single file”, light scatters at
different angles, instrument detects. Provides cell number, cell volume, and
cell complexity.
- Benchtop machines
Clinical Chemistry:
- Liver: ALT, ALP, AST, GGT, total protein, albumin, bilirubin, cholesterol,
glucose, BUN
- Kidneys: BUN, creatinine, electrolytes
- Muscle: CK, AST
- Proteins: Total proteins, albumin, globulin
- Minerals: calcium, magnesium, phosphorus
- Electrolytes: Sodium, potassium, chloride, ALP
- Endocrine: Glucose, sodium, potassium, ALP
- Acid-Base Balance: Anion gap, chloride, bicarbonate
, Serum: Harvest generally more than compared to plasma. Allow time to clot and
retract prior to centrifugation. Can take at least 30 minutes to maximize the
amount of serum.
Plasma: Can centrifuge immediately, no need to wait for a clot to form and retract.
This is preferred for emergent samples.
Hemostasis Test:
Sample handling depends on the specific test.
- Primary Stage: Platelet count and Platelet Estimate, Buccal Mucosal
Bleeding Time, Von-Willebrand Factor assays, Platelet Function Tests
- Secondary Stage: Pro-thrombin Time, Partial thromboplastin time, Activated
coagulation time, Fibrinogen, specific coagulation factor assays.
- Tertiary Stage: Fibrinogen degradation products, and D-dimers
Blood Smear:
Parts of a Smear – Feathered edge, monolayers, and body
Looks at:
- Morphology of RBCs, WBCs, or platelets
o Abnormal Shapes – poikilocytes
o Size – macrocytes, microcytes, anisocytosis (variation in size)
o Color – Hypochromasia, polychromasia
o Inclusions:
Siderocytes, basophilic stippling, Howell-Jolly, Heinz bodies
o Patterns:
Agglutination: RBCs are grouped like grape clusters.
Can artifactually increase the MCV
Occurs when Ab from one RBCs usually IgM
Presence is supportive of immune-mediated hemolysis
