Blood Sample Collection

Question 1

What is venepuncture?

Answer 1

The puncture of a vein to draw blood. Also called phlebotomy.

Question 2

When should blood sampling ideally be performed?

Answer 2

• Prior to fluid therapy/drug therapy
• In animals fasting overnight, as recent feed may effect conc in triglyceride, causing lipaemia (high level of fat in the blood), glucose, cholesterol, urea
• Fasting not advisable in neonatal patients

Question 3

What can occur in a patient that is stressed while having a blood sample taken?

Answer 3

• Leukocytosis (increased WBCS), particularly cats
• Increased packed cell volume due to splenic contraction, particularly dogs
• Hyperglycaemia due to breakdown of glycogen to glucose by cortisol, both dogs and cats

Question 4

What are the common sites for venepuncture in a dog or cat?

Answer 4

Jugular, cephalic, or lateral saphenous vein

Question 5

What are common sites for venepuncture in horses or cattle?

Answer 5

Distended jugular vein, coccygeal vein on the ventral aspect of the tail (runs down midline)

Question 6

What is haemolysis? what can cause it?

Answer 6

Destruction/rupture of RBCs (erythrocytes). Caused by small gauge needles

Question 7

What materials are needed for skin prep before phlebotomy?

Answer 7

Chlorohexidine (hibiscrub) and 70% Isopropyl alcohol,

Cotton swabs to clean skin sight, blood tubes, clippers with size 40 blade, dry swab and vet wrap

Question 8

What is a centrifuge?

Answer 8

Used to spin down blood. It speeds up the process of plasma/serum formation in blood collection tubes, Normally the speed chose is 1500 g x 10 mins

Question 9

What Is a plasma blood sample?

Answer 9

When blood sample is allowed stand for 30/60 mins, the red cells go to the bottom, platelets/erythrocytes to the middle and plasma on top

Question 10

What is a serum blood sample?

Answer 10

When there is no anti coagulant used in the blood collection tube, the blood sample clots. The fluid above the clot is called serum

Question 11

What is the cause of lipaemia in blood samples? (milky white colour of the serum or plasma)

Answer 11

Failure to fast an animal 12 hours before blood sampling, occurs especially after ingestion of fatty food. If lipaemia seen in fastened animal it suggest underlying problems e.g.: cancer, diabetes, pancreatitis

Question 12

What does yellow coloured plasma or serum indicate?

Answer 12

Large conc of bilirubin in the body. Horses have no gall bladder so their plasma may appear more icteric than a dog or cat.

Question 13

What are the guideline for the storage of serum and plasma?

Answer 13

Store in fridge at -20C if not being analysed soon, should be thawed in a water bath of 37 C(freezing and thawing should only be done once)
Place in fridge of 4C if being analysed soon. Serum/plasma samples can be sent to labs with icepacks during transit keeping it between 4-8 C

Question 14

What is haematoma?

Answer 14

Localised bleeding outside of the blood vessels