Venipuncture Sites
What are the 3 common venipuncture sites in dogs?
Cephalic, jugular, lateral saphenous
What is EDTA mainly used for?
CBC
EDTA preserves cell shape and prevents clotting by binding calcium.
What type of sample is used for a smear?
EDTA whole blood
What does PCV measure?
Percentage of RBCs in blood
Indicates oxygen-carrying capacity.
What does lipemia look like?
Milky plasma
Milky → high fat content.
What vein is used most commonly in cats?
Medial saphenous
What tube is used for coagulation tests?
Blue (Citrate)
Citrate binds calcium reversibly, allowing clotting tests to be performed accurately.
What is the MOST common cause of hemolysis during blood collection?
Rough handling
Force (pulling hard, pushing through the needle) breaks RBCs.
Where are RBCs located after centrifuge?
Bottom layer
RBCs are the densest component.
What color is icteric plasma?
Yellow
Yellow → excess bilirubin.
Which vein is best for large-volume blood collection?
Jugular
Why is heparin NOT used for blood smears?
Interferes with WBC staining
Heparin causes poor stain quality, making cell identification difficult
What angle should the spreader slide be?
30°
What is the buffy coat?
WBCs and platelets
Thin middle layer between RBCs and plasma.
What causes hemolysis appearance?
RBC breakdown (reddish plasma)
Red → RBC rupture.
What is a reason we wouldn't pull blood from the jugular?
Coagulation Disorders, Head Trauma, Respiratory Distress, Local Trauma or Infection
Why should samples be run within 1 hour or refrigerated?
Prevent cellular degradation and inaccurate results
Cells break down over time, altering morphology and lab values.
Why should alcohol be allowed to dry before venipuncture?
Prevent hemolysis and sample contamination
Wet alcohol can damage RBCs and dilute the sample.
What does a low PCV indicate?
Anemia
Anemia → fewer RBCs.
Which condition would MOST interfere with lab testing due to turbidity?
Lipemia
Lipemia→ Cloudiness disrupts machine readings.
Why should stress be minimized during collection?
Prevent splenic contraction affecting results
Stress causes the spleen to release stored RBCs, falsely elevating PCV/RBC counts.
Which tube works by inhibiting thrombin and thromboplastin?
Heparin
Heparin directly interferes with clotting factors rather than binding calcium.
Why must the smear be air-dried immediately?
Prevents cell distortion/artifacts
What does a high PCV indicate?
Dehydration or polycythemia
Dehydration or polycythemia → concentrated RBCs.
What causes icteric plasma?
Increased bilirubin (liver disease)
Increased bilirubin → liver dysfunction.