IACUC Procedures FAQs
Blood Withdrawals
Guidelines for Blood Withdrawals
The type of test and amount of blood needed will govern the method and sites of collection.
When venipuncture is required, hair should be clipped from the site and the area should be
cleaned with alcohol. When collecting blood from the rabbit ear or mouse tail vein, heat (warm
water bath) or xylene applied to the area may be helpful. Note: xylene is a dermal inflammatory
agent and must be cleaned off with alcohol and water after blood collection is completed.
After occluding the vein manually or by tourniquet, the needle is inserted parallel to the vein and
the tip directed into the lumen along the longitudinal axis. When withdrawing blood, slow and
gentle aspiration helps prevent collapse of the vein. Gauze held firmly in place at the blood
collection site for a few minutes after withdrawal of the needle, will prevent the formation of
hematomas.
The following tables list common blood withdrawal sites and recommended needle length and
gauge for use in laboratory animals.
Note: Heart puncture and orbital bleeding are acceptable only if the animal is properly
anesthetized. Laceration of the marginal ear vein of rabbits is considered to be unnecessarily
traumatic and is frequently associated with post-procedural hemorrhage. Heart puncture should
be limited to terminal procedures with the exception of the guinea pig.
VOLUME
OBTAINED*
ANIMAL
SITE
NEEDLE GAUGES
Mouse
Heart**, tail vein (D),
retro-orbital plexus
0.2 - 0.5 ml
(least preferred & will
required justification)
5/8" 25 ga
5/8" 27 ga
Rat
Heart**
Retro-orbital plexus
Tail vein (D)
Saphenous vein (D)
5 ml
0.5 - 1 ml
0.5 - 1 ml
0.5 - 1 ml
1" 22 ga
Hct tube
5/8" 25 ga
5/8" 25 ga
Domestic Fowl
Brachial Vein
5 - 10 ml
22 ga