Retro-orbital Bleeding


In order to comply with government regulations (PHS and USDA), AAALAC, The Guide for the Care and Use of Laboratory Animals, and standard veterinary care techniques, 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:  August 20, 2020 through June 30, 2023

This policy has been approved by a majority vote of the IACUC members