Ch 43 Blood Specimen Collection

Capillary punctures

Also referred to as finger sticks; ideal for screening tests requiring a small amount of blood.

Capillary puncture direction

Should be made across fingerprints, not parallel to them.

Venipuncture

The surgical puncture of a vein, also referred to as phlebotomy; most common site is the inner arm at the bend of the elbow.

Phlebotomy

Another term for venipuncture.

Three methods of venipuncture

Sterile needle/syringe method, vacuum tube/sterile needle method, and butterfly needle method.

Color-coded stoppers

Seals on blood collection tubes that assist in indicating what type of tests can be performed with them.

Order of draw

(1) Blood cultures

(2) clear (if using a butterfly draw)

(3) light blue - contains sodium citrate

(4) red - contains no additive

or

(4) red/gray - SST or serum separator tubes with or without clot activator or gel separator

(5) Gold - SST or serum separator tubes with or without clot activator or gel separator

(6) green - contains heparin

(7) lavender - contains EDTA; also called CBC tubes

(8) gray - sodium fluoride

Why is it important for the lancet to be positioned to cut across the fingerprints rather than parallel to them?

When made across the fingerprints, blood will form a bead that makes blood collection easier. When made parallel to fingerprints, the blood will most likely run down the fingerprints, making collection difficult.

Why should the lateral sides of the infant’s heel be used for capillary puncture?

Nerve and bone damage can occur if the middle of the heel is used for collection of capillary blood in infants; there are no nerves or bony tissue in the lateral side of the infant’s heel.

Why is the first drop of blood wiped away from the capillary puncture site

The first drop of blood contains tissue fluid that will dilute the specimen and jeopardize the reliability of the test results.

Identify the acceptable sites to perform a capillary puncture on a patient’s hand

The ring finger and the great finger

During the venipuncture procedure, the tourniquet should not remain on the patient’s arm for more than how long?

1 minute (60 seconds)

What is the medical term for abnormal collection of blood immediately below the surface of the skin?

Hematoma

What is the destruction of red blood cells known as?

Hemolysis

Why would a hematoma develop as a result of phlebotomy? What should you do?

Usually, a hematoma is a result of air getting into the site as well as blood leaking from the vessel during the venipuncture process.

• When you notice a hematoma developing, immediately stop the collection of the specimen. Remove the tourniquet FIRST and then withdraw the needle and apply pressure to the site (to help minimize the size of the hematoma and the resulting bruise).

Steps of a capillary puncture

1. Introduce yourself and identify the patient

2. Assemble the necessary supplies

3. Don gloves

4. Disinfect the selected site to dry

5. Allow the selected site to dry

6. Perform the puncture with the lancet, penetrating across the fingerprints

7. Wipe away the first drop of blood

8. Collect the specimen

9. Provide the patient with a clean gauze to apply pressure to the site

10. Dispose of the lancet and contaminated materials in the appropriate biohazard containers