- Resources and references
- Retro-orbital sampling in other animals
- All blood sampling techniques in the rat
Please read the general principles page before attempting any blood sampling procedure.
Also referred to as peri-orbital, posterior-orbital and orbital venous sinus bleeding. Retro-orbital bleeding should be performed as a terminal procedure. It should only be used with recovery in rare circumstances with exceptional scientific justification (e.g. where a large blood volume is necessary or where peripheral veins are used for dosing), because of its potential impact on animal welfare. Adverse effects reported for this procedure are described in the summary below.
Where its use is unavoidable, retro-orbital bleeding should only be used under terminal or general anaesthesia. Because of the severity of the adverse effects that can occur with this technique, even in skilled hands, it is essential that it is conducted only by staff members competent (practised) in the technique.
Blood is collected from the venous sinus. The rat is restrained, the neck gently scruffed and the eye made to bulge. A capillary tube/pipette is inserted medially, laterally or dorsally. Blood is allowed to flow by capillary action into the capillary tube/pipette, ensure proper aseptic technique is used. The sample obtained is a mixture of venous blood and tissue fluid, and is not representative of venous blood.
|Number of samples||It is recommended that only one sample be taken.|
|Sample volume||Up to 0.2 ml with recovery; Up to 0.5 ml non-recovery.|
|Equipment||A glass capillary tube or Pasteur pipette.|
|Staff resource||One person is required to take the blood sample.|
|Other||Careful monitoring for adverse effects is necessary both peri- and post-operatively.|
- Sharma A, Fish BL, Moulder JE, Medhora M, Baker JE, Mader M, Cohen EP (2014). Safety and blood sample volume and quality of a refined retro-orbital bleeding technique in rats using a lateral approach. Lab animal 43(2): 63
- Diehl KH (2001). A good practice guide to the administration of substances and removal of blood, including routes and volumes. Journal of applied Toxicology 21.1: 15-23
- Luzzi M, Skoumbourdis E, Baumans V, Conte A, Sherwin C, Kerwin A, Weilenmann RF. (2005). Collecting blood from rodents: a discussion by the laboratory animal refinement and enrichment forum. Animal Technology and Welfare 4(2): 99-102
- Hoff J (2000). Methods of blood collection in the mouse. Lab Animal 29:10
- Forbes N, Brayton C, Grindle S, Shepherd S, Tyler B, Guarnieri M (2010). Morbidity and mortality rates associated with serial bleeding from the superficial temporal vein in mice. Lab Animal Europe 10(9): 14-22