This SOP sets standard procedure for the collection of blood from rabbits. These procedures have been reviewed and approved by the Animal Care and Facilities Committee. Using these procedures will facilitate the review and approval of your protocol. Investigators wishing to use these procedures must still obtain an approved research protocol for the use of animals and must comply with all other stipulations of the Animal Care and Facilities Committee. Deviation from these procedures may be allowed but require specific justification and the written approval of the Animal Care and Facilities Committee.
It is the responsibility of the Principal Investigator to ensure that the personnel involved in research projects are appropriately trained. Persons that have not attempted these procedures should contact the Office of Laboratory Animal Services (732) 932-4168 for training. Training is offered at convenient locations and at no charge.
Useful for obtaining small quantities (0.1 to 5.0 ml).
Place the rabbit in a rabbit restrainer. Using clippers, remove the hair from the ear. Place a finger, loosely fitting paper clip, or other form of light tourniquet at the base of the ear. Use a 25-gauge, 5/8-inch or 22-gauge, 1-inch needle. Small quantities can be collected from the hub of a 25-gauge needle directly into a microhematocrit tube. The larger needle is attached to a syringe and blood is collected slowly into the syringe to avoid collapsing the vein. If blood does not flow readily, there may be a clot formation in the needle or too much negative pressure applied to the syringe. Release the negative pressure and slowly rotate the needle. Repeat these steps as needed until the desired quantity of blood has been collected.
For multiple blood collections from veins, start proximally (closer to the base of ear), and work distally. Remove the tourniquet when collection has been completed. Apply pressure to the collection site until bleeding stops. If whole blood is needed, the syringe should be pre-treated with an anticoagulant.
Use for large quantities (5 to 50 ml).
A tranquilizer, such as Innovar-Vet or Ace-Promazine, works very well as a vasodilator as well as providing a tranquilizing effect. Administer Innovar-Vet at a dose of 0.1 to 0.2 ml per rabbit SQ or IM; or Ace-Promazine 0.25 to 0.5 mg/kg SQ or IM. The best results are obtained when administered 10-15 minutes prior to blood collection.
Place the rabbit in a rabbit restrainer. Using clippers, remove the hair from the ear. A 1 to 1-1/2-inch needle ranging in size from 22-gauge to 20-gauge is recommended for blood collection. Some investigators prefer to break off the hub of the needle and use the needle shaft for collection or to use a vacutainer needle. Extend the ear away from the rabbit’s head to provide a flat surface and insert the needle into the artery. Once blood begins to flow, lower the ear and position the receptacle under the needle for blood collection. Occasionally, the artery may constrict during the collection process, shutting off the flow of blood. Hold the needle securely in place until the rabbit relaxes, usually within one minute. Gentle massage of the artery at the base of the ear may enhance blood flow. Clot formation in the needle can also prevent blood flow. If no blood flows, remove the needle and repeat the procedure using a new needle. Insert the new needle into the artery proximal to the previous site (closer to the base of the ear).
Some experienced operators find it helpful to handle the rabbit without undo stress and to provide supplemental heat to the ear from a 100 watt light bulb. Both practices will help to dilate the vessels.
For multiple blood collection from the auricular artery, start distally and work proximally. The volume of blood removed at any one bleeding should not exceed 1% of body weight. The maximum recommended blood draw is 10 ml/kg weekly, up to 4 weeks. Weekly bleedings exceeding one month requires monitoring of hematocrit, hemoglobin and total plasma protein.
To enhance hemostasis at the conclusion of the blood collection, lightly compress the collection site as the needle is removed. Arterial collection may require up to 5 minutes of pressure. A paper clip placed at the site of puncture may be used instead of digital pressure.
Blood collection from the heart, cardiocentesis.
This technique requires heavy sedation with an analgesic or general anesthesia and is limited to terminal collections due to the danger of fatal hemorrhage and pneumothorax. This technique requires specific written approval from the Animal Care and Facilities Committee.