Needle Size

The table below lists the maximum acceptable needle size for administration or sampling. Select the smallest gauge possible for injections and sampling, to minimize stress to the animal, and the chance of leaking from puncture site after the needle is withdrawn.

Approximate volumes for fluid replacement therapy by intraperitoneal or subcutaneous administration

SpeciesMethodNeedle SizeSiteVolume
MouseSQ25 gaugeScruff of neck1-1.5mL at 2-3 sites
 IM25 gaugeQuads, post, thigh0.03mL
 IP25 gauge 1-2mL
 IV25 gaugeLateral tail vein0.2-0.4mL
 Gavage22 gauge, 2-3 cm, feeding needle 5-10mL/kg
(1mL/mouse)
RatSub-Q25 gaugeScruff, back5-10mL (2-3 sites)
 IM25 gaugeQuads, post, thigh0.03mL
 IP25 gauge 4-5mL
 IV23 gaugeLateral tail vein0.5mL
 Arterial25 or 27 gaugeVentral tailwithdraw only
 Gavage18 gauge, 6-8 cm long 5-10mL/kg(3mL/rat)
RabbitSub-Q23 or 22 gaugeScruff, back30-50mL (2sites)
 IM23 or 25 gaugeQuads, lumbar muscles0.5-1.0mL
 IV23 gaugeMarginal ear vein1 - 5ml (slowly) withdrawn only