Blood Sampling

Question 1

Role of SVN

What nursing skills are vital?

Answer 1

Communication

Preparation

Sampling
- correct sample, methods, storage, procedures, transportation.

Record Keeping

Communication of results

Understanding finding
- limitations of tests, relevance, recognition of spurious values

Health and Safety

Question 2

Role of SVN

What should be checked before each test is carried out?

Answer 2

Check with vet which test to carry out.

Patient ID

Clinical History

Equipment available and working

Safe area to work

Other members of staff available to collect sample

Question 3

What common laboratory tests are carried out?

Answer 3

Blood
Urine
Faeces
Skin and Hair
Tissues and Body fluids for cytology
Samples for Toxicology, bacteriology, fungal, viral culture

Question 4

What is PCV?

Answer 4

The % of the total blood volume which is made up of red blood cells.

Quick test that rapidly gives information on hydration status, degree of anaemia/blood loss in an animal.

Question 5

Which tube is used for a PCV?

Answer 5

ETDA tube (pink/red lid)

Gently invert the blood within the tube to mix the sample. Place your microhaematocrit tube into the blood and allow the tube to fill ¾.

Once the tube is ¾ place your index finger over the top of the tube to prevent back flow of blood.

Seal your haematocrit tube using plastocine sealant.

Question 6

What setting do PCV samples need to be in a centrifuge at and for how long?

Answer 6

10000 rotations per minute for 5 minutes

Question 7

Once spun down, what are the 3 layers that make up the sample?

Answer 7

Plasma
Buffy coat
Red blood cells

Question 8

What are the normal PCV ranges in dogs and cats?

Answer 8

Dog - 37-55%

Cat - 24-45%

Question 9

What can an increase in PCV indicate?

Answer 9

Dehydration due to reduced plasma levels

Question 10

What can a decrease in PCV levels indicate?

Answer 10

Anaemia or haemorrhage due to fewer red blood cells

Question 11

What sizes needles are used to obtain a blood sample in dogs and cats?

Answer 11

Dogs - 21G
Cats - 23G

Question 12

What syringe should be used when taking a blood sample?

Answer 12

A clean, dry and disposable one.

Question 13

Why is it important to never drawback hard on syringe plunger when taking a blood sample?

Answer 13

It could collapse the vein

Question 14

What is important to remember when obtaining a blood sample?

Answer 14

Always transfer blood to a collecting tubes soon as possible to prevent contaminating and clotting.

Always expel the blood gently into the tube to prevent cells damage.

Important to collect enough blood to fill the required level on collection tube.

Question 15

How quickly does blood normal clot?

Answer 15

In 10-20 seconds after contact with tissue, tissue fluids, glass, or plastic.

Question 16

What are the most common venous blood sampling sites?

Answer 16

Cephalic
Jugular
Saphenous
Lateral

Question 17

What equipment is needed to prepare for a blood sample?

Answer 17

• Restraint aids
• Correct blood tubes
• A sterile syringe
• A 21-23G sterile needle and spares. Needle is bevel-up and syringe’s plunger is pre-loosened
• Antiseptic skin preparation
• Hand wash +/− gloves
• Sharps bin.
• Swab for post-venepuncture pressure
• Bandage materials for prolonged pressure
• Good light source
• Clean, functional clippers

Question 18

Why do we occlude the vein?

Answer 18

Causing pooling of blood and venous engorgement.
Makes the vein easier to visualise, feel, and assists in making a good volume of sample easier to obtain.

Question 19

What ways can a blood sample be preserved?

Answer 19

Blood tube containing anticoagulation to prevent clotting.

Blood tube containing no anticoagulation to allow sample to clot and serum to be removed.

Blood smear to view under microscope.

Question 20

What is the use of anticoagulants?

Answer 20

Plasma forms.
Prevents blood clotting.
Must be appropriate anticoagulant for the diagnostic test.
Blood sample must be quickly and gently placed into correct blood tube and mixed gently.

Question 21

What is the use of no anticoagulants?

Answer 21

No anticoagulation in blood tube so serum is formed from clotted sample.
Used for serology and biochemical tests.
Serum can be extracted.

Question 22

Which tests are anticoagulation used for?

Answer 22

• Sodium Citrate: Coagulation studies, von Willebrand factor(vWF) and other clotting assays
• Serum/plain: General Biochemistry, endocrinology, serology, and therapeutic drug monitoring
• Lithium Heparin: Biochemistry, some special biochemistry if serum is unavailable (chemicals and enzymes)
• EDTA: Haematology (complete blood count, red/white, fibrogen, haemoglobin concentration, total protein, blood smear evaluation,
• Fluoride Oxalate: Glucose

Question 23

What is the fluid part of blood?

Answer 23

Plasma - a clear straw coloured liquid that contains mineral salts, plasma proteins.

Separates out when a blood sample is spun in a centrifuge.

Question 24

What is the solid part of blood?

Answer 24

Consists of red blood cells and fragments of blood cells suspended in plasma.

Question 25

What are the 3 groups of blood cells?

Answer 25

ERYTHROCYTES – red blood cells
LEUCOCYTES – white blood cells
THROMBOCYTES (platelets) – fragments of cells

Question 26

What can be done to avoid haemolytic of a blood sample?

Answer 26

• Excessive suction
• Blood passes through needle once to avoid cell damage
• Remove needle when transferring blood sample to sample container
• Use widest gauged needle that’s practical for patient and shortest length
• No water to avoid osmostic damage to blood cells
• DON’T SHAKE SAMPLES
• Examine asap
• Store at cool 4 degrees temperatures
• Avoid sunlight
• Package correctly to external labs