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Copyright 2006, University of Minnesota Board of Regents.

The University of Minnesota is an equal opportunity educator and employer.

Facial Vein 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


  1. 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)
  2. Place the mouse on the wire bars of the cage (or other work surface).
  3. Line up the mouse so that its nose is pointing back toward the wrist of the restraining hand.
  4. Cup the free hand over the mouse, and scruff it firmly using the thumb and first finger.
    1. NOTE:  It is critical that you hold a lot of skin.  Your fingertips should be touching or almost touching the mouse’s elbows.
    2. 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

  1. 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.
  2. You should now have the mouse gently and securely restrained in your non-dominant hand, and be able to pick the mouse up.
  3. Locate the hairless freckle on the side of the jaw.
  4. Pick up the sharp instrument of your choice (lancet or needle) with your free hand.
  5. 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.
  6. Prick the freckle with the lancet.  If using an 18 gauge needle, go in only up to the depth of the bevel.
  7. Quickly drop the sharp into the sharps container and pick up your collection tube.
  8. Collect 4-7 drops of blood (maximum amount depends on frequency of bleeding—when in doubt, contact an RAR veterinarian)
  9. Release the mouse into its cage when you have obtained your sample.  Bleeding should cease immediately.


  1. News release. http://www.ars.usda.gov/is/pr/2005/050921.htm



Q:  Mouse pushes needle away with front foot.
A:  Scruff more skin so front legs can’t move

Q:  Mouse arches its back and scratches with back feet.
A:  Scruff more skin; hold tail securely between fingers.

Q:  Mouse doesn’t bleed.
A:  Scruff more tightly to hold off vein.  Prick freckle just under bone, pointing toward far eye.  Try the other side if necessary.

Q:  Mouse tongue and/or lips turn purple.
A:  Release mouse, scruff less skin.

Q:  Mouse keeps bleeding.
A: Put gentle pressure on face over prick.

For video clips, see the following commercial video at Medipoint:
(Windows Media) http://www.medipoint.com/html/directions_for_use1.html
(Quicktime) http://www.medipoint.com/html/directions_for_use2.html

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The information contained in this site is intended as a reference for University of Minnesota investigators, and animal husbandry and veterinary staff. Drug information and dosages are derived from a variety of sources and do not necessarily guarantee safety or efficacy. Information obtained through this site should not be relied upon as professional veterinary advice. Any medications administered or procedures performed on animals should only be performed by or under order of a qualified, licensed veterinarian.