Tuesday, February 24, 2009

How to draw your own blood

First of all you will need an appropriate blood tube or clot tube for the test you will be performing or taking the blood in for (will cover blood tubes and tests more extensively another post). Some tests will need the blood seperated and should not be drawn without a vet unless you have a centrifuge to seperate at the appropriate time, contact vet or lab to ensure that whole, non-seperated, blood may be sent) You will also need a needle (20-22 ga. X 1") or vacutainer (large amounts of blood) and sterile syringe (Size depends on amount needed, most only need 3 cc, call vet or lab and ask amount when in doubt). You may also need a clipper for shaving the hair off close if not experienced (I would advise having someone show you in person how to do this at least once). You should have an alcohol swab (or chlorahexidine, or Iodine) and cotton balls as well. You should also have a black pen available and should write the animal's ID on the blood tube as soon as possible, especially when doing more than one animal. Most often at least two people are needed for blood draws, one for restraint and one for drawing the blood. It is also advised to wear gloves.

You will need to restrain the animal properly. For a milking goat this may be as simple as the milking stand with head secured and eating. For a cow it can be done in a stanchion. Some dogs will need fully restrained some will just need securely held. (will also cover proper restraining methods in future posts) Please stay tuned and learn more about performing these holds BEFORE attempting.

The site for the blood collection depends on the species of animal. Most large animals and small ruminants (cows, horses, sheep, goats) are drawn from the neck. Dogs can be drawn from the neck or foreleg. Cats can be drawn from the neck, foreleg, or interior hind but are difficult to do. I would recommend a large animal for your first veinupuncture as they are the easiest to restrain and the easiest to draw from.

To locate the vein in the neck you can imagine a line directly down from the center of thier eye down their neck. Have the restraint person tip the animals muzzle upwards and away from you and hold it securely there. There should be a valley or furrow in the neck. The vein is located within this furrow. Apply pressure about 3/4 of the way down the neck where the furrow is the deepest. You should see the vein bulge outwards above your hand within the furrow. Congratulations you found your vein. It can be found on either side of the neck. If needed shave the area to be able to visualize the vein better, if you don't want to shave wetting down the area with alcohol may also help. Animals that are overweight may have veins that are harder to locate due to excess fat.The restraint person does not hold pressure for you.

The other main vein that is used is the cephalic. It is in the forearm. Restrain the animal by holding one arm under the neck and the other arm over the body. The arm that is held over the body also will be used to put pressure on the vein. The restraint person holds the pressure (you may also use a tourniquet). To hold pressure on the vein place hand over arm of animal with thumb pointing towards the inside and belly and fingers pointing outwards and down. Grasp top of leg firmly and roll outward.This will make the vein bulge slightly lower down the arm.This bulge is the location for the blood draw.

Syringe and Needle Method: Remove the cap from the needle. The plunger of the syringe can be operated by using the thumb, forefinger and the middle of the hand. Before inserting the needle, pull the plunger back to break the seal on the syringe, and then depress completely to remove the air. Use the thumb of one hand to place pressure on the vein as described above. Hold the syringe in the other hand and guide the needle towards the bulging vein. Insert slightly and gently pull back on the plunger using the ring and pinky fingers of the hand holding the syringe. If blood appears in the syringe, continue filling the syringe until the desired amount is obtained. If no blood is seen, the needle may be parallel to the vein or it may have gone through the vein. Light movements of the syringe can be used to try to locate the vein. If the vein cannot be found withdraw the needle and start again on the other side or slightly above the first puncture after applying pressure to first side with a cotton ball soaked in alcohol for several minutes. Once the sample has been taken, remove the pressure from your thumb on the vein, withdraw the needle and apply pressure to the site until all bleeding stops.

Vacutainer Method: With the thumb of one hand hold off the vein which should be easy to see and feel. Aim for the center of the vessel. Inserting the needle does not require a lot of force- apply just enough pressure to break through the skin and enter the vessel. Once the needle is in place, apply pressure to the tube so it is pushed up onto the vacutainer needle. If the needle is in the vein, blood should flow into the tube. If this does not happen, gently move the needle out of the vessel (while still on the tube), but not out of the skin (or the vacuum will be lost) and redirect the needle until blood enters the tube. When the tube has filled with the desired amount, release the pressure from your thumb on the vein, remove the tube from the needle and then remove the needle from the skin. Apply pressure until all bleeding has stopped.

Insert needle directly into top of blood tube and allow vacuum to suck blood from syringe into tube (do not forcefully depress plunger, if blood tube was not opened prior to this there should be a vacuum within it) Never handle blood roughly, do not shake, inject forcefully, or anything else that could damage blood cells. This will cause your results to be skewed or unusable.

CAUTION: Never allow air to be injected into a vein, always ensure that the syringe is empty of air before beginning. When needle is under the skin of the animal and no blood comes out there should always be pressure pulling on the syringe plunger if plunger is pulled on. If there is no pressure on the plunger and plunger is not flush with the front of syringe there is air in the syringe and the needle should be withdrawn from the animal immediately without depressing the plunger.

It is always a good idea to contact vet or testing lab before starting for blood handling instructions. Place blood tube carefully into the refrigerator if required. After 5 hours or so you can send it to the lab for testing. If it is warm outside you may need to put a small cold pack in with it when you mail it.

Some animals should only be done with experience. Below are a few odds and ends animals.
Swine Blood Draws
Alpaca Blood Draws
Rabbit Blood Draws

Here are a few laboratories that may be able to process your blood sample. If there is not one listed in your area, try calling the one that is nearest to you. They probably know of another lab that is closer.

California Veterinary Diagnostic Lab System
West Health Sciences Drive
University of California - Davis
Davis, Calif. 95616
(916)752-7577

National Animal Disease Center
PO Box 70
Ames, Iowa 50010

Pan American Veterinary Laboratories
3921 Steck Ave
Austin, Texas 78759
(512)794-9657 Fax
(800)856-9655

Veterinary Diagnostic Laboratories
University of Minnesota
College of Veterinary Medicine
Carter and Gortner Aves.
St Paul, Minnesota 55108

Washington Animal Disease Diagnostic Laboratory
College of Veterinary Medicine
Washington State University
PO Box 2037
College Station/Bustad Hall, Rm 155-N
Pullman, Washington 99165-2037
(509)335-7424 Fax
(509)335-9696

Diagnostic Laboratory
Cornell University
College of Veterinary Medicine
Ithaca, New York 14853

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