Decision tree

How much blood does a mouse have?

On average, mice have around 58.5 ml of blood per kg of bodyweight.

A mouse weighing 25 g would therefore have a total blood volume (TBV) of approximately 58.5 ml/kg x 0.025 kg = 1.46 ml.

How to decide on the most appropriate blood sampling technique for mice?

The two tables below are designed to assist in determining the amount of blood to sample from the animal, and depending on that volume, the most appropriate techniques to use.

1. Do you require more than one blood sample from the same mouse?



Maximum <10% TBV (= 0.14 ml) on any single occasion AND <15% TBV ( = 0.21 ml) in 28 days

Maximum <10% TBV ( = 0.14 ml)

For repeat bleeds at short intervals, suggested limit <1% TBV ( = 0.01 ml) in 24 hours AND consider cannulation

OR terminal sample under general anaesthesia (volume unrestricted)


2. How much blood do you require?

Total of <0.20 ml

Total of >0.20 ml

General anaesthesia required

General anaesthesia not required

General anaesthesia required
Non recovery

Saphenous vein

Tail vein

Sublingual vein

Retro-orbital $

Saphenous vein

Tail vein

Mandibular vein

Blood vessel cannulation **

Tail snip *

Cardiac puncture

Abdominal / thoracic blood vessel


Decapitation #

$ Only in exceptional circumstances
* Mixed arterial / venous sample will be obtained
# Blood may be mixed with tissue fluid
** Cannulation surgery performed under general anaesthesia