Retro-orbital Bleeding


In order to comply with government regulations (PHS and USDA) and the American Association for the Accreditation of Laboratory Animal Care (AAALAC) and The Guide for the Care and Use of Laboratory Animals, 8th edition (NRC, 2011) and standard veterinary care techniques, the UConn Health’s Institutional Animal Care and Use Committee (IACUC) has implemented a policy concerning retro-orbital eye bleeding.


1. All animals must be appropriately anesthetized prior to performing procedure.

2. Maximum blood collection volumes (mouse):

  • Weekly sampling (0.6% body weight):                      115μL (25g mouse)
  • Biweekly sampling (0.8% body weight):                    200μL (25g mouse)
  • Monthly sampling (no fluid replacement, 0.6%):         200μL (25g mouse)
  • Monthly sampling (with fluid replacement, 1.5%):       350μL (25g mouse)

3. Maximum blood collection volumes (rat):

  • Biweekly sampling (1.5% body weight):                     3.5 mL (250g rat)

4. Multiple retro-orbital plexus bleeding requires the use of alternate eyes each time the procedure is performed.

5. No bleeding may be performed from a damaged eye. In the event that both eyes are damaged, eye bleeding must cease.

6. Volumes greater than the maximum volumes listed above require scientific justification and prior approval by the IACUC.

7. Investigators should maintain familiarity with the Center for Comparative Medicine guidelines regarding retro-orbital plexus bleeding.

Effective Dates:  October 26, 2017 through September 30, 2020