LEARNING OBJECTIVE: Identify the correct steps to perform blood collection by the finger puncture method and venipuncture method, and recall Standard Precautions and other safety precautions that apply to blood collection.

There are two principal methods of obtaining blood specimens: the finger puncture method and the venipuncture method. For most clinical laboratory tests requiring a blood specimen, venous blood obtained by venipuncture is preferred. Blood collected by venipuncture is less likely to become contaminated, and the volume of blood collected is greater. Infection control practices, equipment requirements, and step-by-step instructions on performing both of these blood collection methods will be discussed in the following sections.

STANDARD PRECAUTIONS
Under the concept of "Standard Precautions" outlined by the Centers For Disease Control and Prevention (CDC), blood and other bodily fluids should be considered as potentially infectious. To protect medical personnel from direct contact with blood during phlebotomy (blood collection), gloves are required to be worn. Gloves should be disposed of after each patient.

Needles and sharps used in the blood collection process should be handled with extreme caution and disposed of in biohazard sharps containers. Sharps containers should be conveniently located near phlebotomy work sites.

Absorbent materials, such as cotton 2 x 2'sused to cover blood extraction sites, normally contain only a small amount of blood and can be disposed of as general waste. However, if a large amount of blood is absorbed, the absorbent material should be placed in a biohazard waste container and treated as infectious waste.

Clean phlebotomy work site equipment and furniture daily with a disinfectant.

FINGER PUNCTURE
The finger puncture method is used when a patient is burned severely or is bandaged so that the veins are either covered or inaccessible. Finger puncture is also used when only a small amount of blood is needed.

Materials Required for Finger Puncture Procedure

To perform a finger puncture, the following materials are required:

Sterile gauze pads (2" x 2")

Figure 7-2.-SF-545, Laboratory Report Display.

70% isopropyl alcohol or povidone-iodine solution pads
Blood lancets
Capillary tubes
Bandages
Arrange your equipment in an orderly manner and have it within easy reach. Also, wash your hands before and after each procedure.

Finger Puncture Procedure
To perform a finger puncture, follow the steps given below.

1. Explain the procedure to the patient.
2. Using the middle or ring finger, massage or "milk" the finger down toward the fingertip. Repeat this "milking" five or six times.

3. Cleanse the fingertip with an alcohol pad or povidone-iodine solution and let dry.

4. Take a lancet and make a quick deep stab on the side of the finger (off-center). To obtain a large rounded drop, the puncture should be across the striations of the fingertip. See figure 7-3.

5. Wipe away the first drop of blood to avoid dilution with tissue fluid. Avoid squeezing the fingertip to accelerate bleeding as this tends to dilute the blood with excess tissue fluid, but gentle pressure some distance above the puncture site may be applied to obtain a free flow of blood.

6. When the required blood has been obtained, apply a pad of sterile gauze and instruct the patient to apply pressure, then apply a bandage.

When dealing with infants and very small children, the heel or great toe puncture is the best method to obtain a blood specimen. This method is performed in much the same way.