Best Practice for Collection, Testing and Understanding of Blood Results
World Small Animal Veterinary Association Congress Proceedings, 2018
T. Mothershaw; M. O’Leary; S. Crampton; C. Harvey-Stevenson
Provet, AIRC, Brisbane, Australia

Blood Collection

Blood collection is an important part of everyday veterinary practice. Many factors are taken into consideration when deciding where to withdraw the sample. This includes:

  • Type of animal
  • Size of animal
  • Medical condition/site of injury
  • Amount of blood to be collected
  • Tests to be performed
  • Experience of person taking sample

When taking a blood sample, the procedure should be performed in an aseptic manner. This includes:

  • Clipping of site
  • Preparation of site with surgical scrub solutions
  • Washing hands
  • Sterile needle and syringe

The sample should always be a ‘clean stick,’ otherwise haemolysis of the sample will occur, which may affect test results.

The aim when collecting blood is:

  • To use a vein close to the surface of the body
  • To be able to gently withdraw a suitable volume of blood (to minimise damage to blood cells)
  • To cause minimal disturbance and discomfort to the animal

Preferred Sites for Blood Collection

In small animal practice the jugular vein is often the preferred site for collection. However, if performing tests requiring only a small amount of blood (e.g., glucose, PCV/TPP), peripheral veins may be used.


Vena jugularis, vena saphena and vena cephalica for central venous blood. Edge of ear (close to base) for peripheral blood smears


Same as dog but avoid saphenous and cephalic veins if at all possible

Pocket pets

Tail vein (e.g., rats, ferrets, guinea pigs, etc.)


Jugular vein, brachial artery (for large parrots), pedal artery (large water fowl)


Jugular vein


Jugular vein, tail vein


Collection site

Suggested needle size*

Cat and small dog cephalic or saphenous vein


Cat and small dog jugular vein


Medium to larger dog cephalic or saphenous vein


Medium to larger dog jugular vein


Horse jugular


When transferring blood from the syringe to the tube, steps are taken to minimise damage to the cells:

  • Remove needle from syringe so that blood is not transferred through a small bore.
  • Remove top from tube. This applies equally to a vacuum collection tube as to a screw-top tube unless specifically stated by the manufacture. Plunging a blood-filled syringe + needle into a vacuum tube and allowing it to transfer into the vacuum tube increases the possibility of haemolysis.
  • Gently expel the blood into the angled tube so it dribble down the side.
  • Replace lid securely and (in an anticoagulant tube) gently agitate to evenly mix chemicals with blood. Do this by slowly inverting the tube every 2–3 seconds for 30 seconds.

Factors during the collection that can influence sample quality


How it may affect the sample

Fear and stress of the animal
Experience and capability of person collecting the sample

Adrenalin release affecting glucose and some white cell count results.

Preparation of the collection site

Contamination of sample will give false results where sample is to be cultured.

Time of day when sample is collected

Some hormone levels vary throughout the day.

Feeding before sample collection

Will give a transient hyperglycaemia and hyperlipidaemia.

Using the correct tube for the required test

Tubes are used for specific tests (e.g., blood in a potassium EDTA tube will give a false potassium level).

Actual site of collection

Arterial gasses cannot be estimated from a venous sample.

Why it is important to conduct preanaesthetic blood tests?

A full patient examination performed by the Veterinarian may not be enough to detect an underlying issue and unfortunately illnesses or diseases can go unnoticed. Preanaesthetic blood tests can check the kidney and liver function, presence of low red blood cell (anaemia), infection or inflammatory disease (high white blood cell count), dehydration (high red blood cell count and high total protein levels).

It is important to know the names and what increased and decreased values could mean to a patient in your nursing care.




Alkaline phosphatase (ALPKP)

Liver disease such as Cushing’s, active bone growth (seen in young pets)


Creatinine (CREA)

Kidney disease


Blood glucose (GLU)

Diabetes, stress (seen in cats)

Liver disease, infection or certain tumours.

Aminotransferase (ALT)

Liver cell injury/damage


Total protein (TP)

Dehydration, inflammatory condition

Decreased liver function, blood loss, gastrointestinal loss and kidney loss

Blood urea nitrogen (BUN)

Kidney disease or dehydration

Liver disease

Packed cell volume (PCV)

Dehydration, marrow cancer



1.  The Animal Industries Resource Centre Course materials – Certificate IV in Veterinary Nursing.


Speaker Information
(click the speaker's name to view other papers and abstracts submitted by this speaker)

Taylor Mothershaw, Cert IV Veterinary Nursing
Provet, AIRC
Brisbane, QLD, Australia

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