• Technique
• Summary
• Resources and references
• Blood vessel cannulation technique in other animals
• All blood sampling techniques in the hamster

Please read the general principles page before attempting any blood sampling procedure.

Technique

Also referred to as peri-orbital, posterior-orbital and orbital plexus bleeding. Retro-orbital bleeding should typically 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.

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 plexus. The hamster 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. The sample obtained is a mixture of venous blood and tissue fluid, and is not representative of venous blood.

Blood flow can be stopped by applying gentle finger pressure to the soft tissue. A finger should be placed over the closed eyelid for approx. 30 seconds.

Following sampling, the animals should be euthanised via an appropriate schedule one method.

Summary

Resources and references

• Jo EJ, Bae E, Yoon JH et al. (2021). Comparison of murine retroorbital plexus and facial vein blood collection to mitigate animal ethics issues. Laboratory Animal Research 37(12). doi: 10.1186/s42826-021-00090-4  
• Meyer N, Kröger M, Thümmler J et al. (2020). Impact of three commonly used blood sampling techniques on the welfare of laboratory mice: Taking the animal’s perspective. PLoS ONE 15(9): e0238895. doi: 10.1371/journal.pone.0238895
• Harikrishnan VS, Hansen AK, Abelson KS et al. (2018). A comparison of various methods of blood sampling in mice and rats: Effects on animal welfare. Laboratory Animals 52(3): 253-264. doi: 10.1177/0023677217741332
• Tsai PP, Schlichtig A, Ziegler E et al. (2015). Effects of different blood collection methods on indicators of welfare in mice. Lab Animal 44(8): 301-310. doi: 10.1038/laban.432
• Fried JH, Worth DB, Brice AK et al. (2015). Type, duration, and incidence of pathologic findings after retroorbital bleeding of mice by experienced and novice personnel. Journal of the American Association for Laboratory Animal Science 54(3): 317-327. PMCID: PMC4460946 
• Sharma A, Fish BL, Moulder JE et al. (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): 63-66. doi: 10.1038/laban.432
• Teilmann AC, Nygaard Madsen A, Holst B et al. (2014). Physiological and pathological impact of blood sampling by retro-bulbar sinus puncture and facial vein phlebotomy in laboratory mice. PLoS ONE 9(11): e113225. doi: 10.1371/journal.pone.0113225
• Holmberg H, Kiersgaard MK, Mikkelsen LF et al. (2011). Impact of blood sampling technique on blood quality and animal welfare in haemophilic mice. Lab Animal 45(2): 114-20. doi: 10.1258/la.2010.010129
• Forbes N, Brayton C, Grindle S et al. (2010). Morbidity and mortality rates associated with serial bleeding from the superficial temporal vein in mice. Lab Animal 10(9): 14-22. doi: 10.1038/laban0810-236
• Heimann M, Käsermann HP, Pfister R et al. (2009). Blood collection from the sublingual vein in mice and hamsters: a suitable alternative to retrobulbar technique that provides large volumes and minimizes tissue damage. Lab Animal 43(3): 255-60. doi: 10.1258/la.2008.007073
• Luzzi M, Skoumbourdis E, Baumans V et al. (2005). Collecting blood from rodents: a discussion by the laboratory animal refinement and enrichment forum. Animal Technology and Welfare 4(2): 99-102. 
• Diehl KH, Hull R, Morton D et al. (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. doi: 10.1002/jat.727
• Hoff J (2000). Methods of blood collection in the mouse. Lab Animal 29(10). 
• van Herck H, Baumans V, Brandt CJ et al. (1998). Orbital sinus blood sampling in rats as performed by different animal technicians: the influence of technique and expertise. Lab Animal 32(4): 377-86. doi: 10.1258/002367798780599794
• van Herck H, Baumans V, van der Craats NR et al. (1992). Histological changes in the orbital region of rats after orbital puncture. Lab Animal 26(1): 53-8. doi: 10.1258/002367792780809048

Retro-orbital sampling in other animals

All blood sampling techniques in the hamster