Taxonomy Block

How to obtain blood samples from the facial vein of a mouse.

New Lancet Offers Painless Bleeding Technique.
How to obtain blood samples from the facial vein of a mouse.

Required: 4-5 mm lancet or 18 gauge needle, small blood collecting tube, clean work surface, and mouse.

Not required: Anesthetics

Pick up the mouse by holding its tail. Use the same hand that you prefer to use when handling needles and pens (the right hand for most people)
Place the mouse on the wire bars of the cage (or other work surface).
Line up the mouse so that its nose is pointing back toward the wrist of the restraining hand.
Cup the free hand over the mouse, and scruff it firmly using the thumb and first finger.
NOTE: It is critical that you hold a lot of skin. Your fingertips should be touching or almost touching the mouse’s elbows.
You know you have enough skin when:
i. The mouse’s eyes bulge out of their sockets (just as if under anesthesia and totally relaxed)

ii. The mouth is held open

iii. The forelegs stick out to the sides

You can tuck the tail between your last two fingers, so that the spine of the mouse is resting next to your knuckles. If you have enough scruff, this is optional.
You should now have the mouse gently and securely restrained in your non-dominant hand, and be able to pick the mouse up.
Locate the hairless freckle on the side of the jaw.
Pick up the sharp instrument of your choice (lancet or needle) with your free hand.
Align your sharp instrument so that you are pointing it at the far side of the mouse’s face, at the base of the far ear or at the base of the far side of the mouth.
Prick the freckle with the lancet. If using an 18 gauge needle, go in only up to the depth of the bevel.
Quickly drop the sharp into the sharps container and pick up your collection tube.
Collect 4-7 drops of blood (maximum amount depends on frequency of bleeding—when in doubt, contact an RAR veterinarian)
Release the mouse into its cage when you have obtained your sample. Bleeding should cease immediately.