Phlebotomy Procedures Skin Puncture
Skin Puncture Collection Of Plasma, Serum, & Whole Blood
Purpose:Procedure for the collection of blood by skin puncture technique
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The following equipment
should be in order before proceeding with the skin puncture procedure:
Specimen Collection Procedure
- Blood Drawing Site:
- For Finger Stick Procedures: The drawing area should be wide enough for the patient's arm to rest comfortably. A chair with a wide, flat, clean surface on the arms will suffice or the patient may be lying in bed.
- For inpatient Pediatric patients, the Pediatric treatment room should be used whenever possible.
- Puncture Equipment: Spring-loaded lancets (Microtainer) are available in regular point (blue color) or medium point (yellow color). Blue lancets penetrate 2.4 mm and are used for finger sticks while yellow lancets penetrate 3.2 mm and are used for heel sticks. Also available are 3 sizes of Tenderfoot (used for finger sticks). These range in penetration depth from 0.85 mm (PINK/WHITE), 1.25 mm (BLUE/WHITE), to 1.75mm (RED/WHITE). There are also three sizes of Tenderfoot (heel sticks). These range in penetration depth from 0.85 mm (WHITE), 1.0 mm (BLUE/PINK), to 2.0 mm tissue damage than the spring-loaded lancets. See Pediatric "Special Considerations" for further explanation of these skin puncture devices.
- Gauze: Non-sterile 2x2 inch gauze squares may be used for finger sticks or heel sticks.
- Blood Collection Devices: Microtainers are available in 5 types:
- Pick-top microtainers which contain no additives for blood bank procedures or for procedures not requiring the serum separator gel.
- Red-top microtainers containing a small amount of serum separator gel for producing serum.
- Purple-top microtainers containing EDTA anticoagulant for use in hematology procedures.
- Green-top microtainer containing heparin and separator gel for use in chemistry procedures.
- Gray-top microtainer containing Na fluoride/K oxalate for use in specific chemistry procedures.
- Microhematocrit capillary tubes are used for collecting blood for the microhematocrit test. These are self-sealing.
Natelson capillary tubes may be used for collecting blood directly from a heel stick. The tube can then be emptied into the appropriate microtubes, if required.
- Gloves: Latex & non-Latex are available in various sizes and may be powdered or be powder free.
- Antiseptics: Individually packaged 70% isopropyl alcohol wipes may be used to clean the puncture site for most specimens. Povidone-iodine swabs may also be used.
- Large Test Tube: It may be impractical to label individual microtainers or capillary tubes. Instead, place the sealed or capped tubes in a single large test tube and label the test tube with the computer specimen label and the microtainers with the aliquot labels. If only adhesive labels available, label the specimen instead of the test tube.
- Adhesive Labels: 1.0x2.5 inch adhesive labels and a permanent marking pet should be available for labeling the specimens. One may also use an addressograph label with name and medical record number.
- Warm Washcloth: A clean, warm, wet washcloth may be used to warm the skin puncture site. It should be 42° C., or 108 degrees F., with additional warm water.
- Chucks: A clean chucks should be available for heel sticks to protect the person holding the baby from dripping blood.
- Sharps Disposal Container: An OSHA acceptable puncture-proof red container marked "Biohazardous" for disposing of lancet or partially filled capillary tubes.
- Disinfectant: A plastic wash bottle with ASCEND germicidal solution should be available for cleaning up small blood spills.
Routine Skin Puncture Procedure
- Assemble necessary equipment described in the Materials and Equipment section of this procedure.
- Wash hands and put on gloves.
- Identify patient.
- Inpatient - the patient's name and Medical Record Number on their ID bracelet much match the requisition or the computer label.
- Outpatient - we make initial ID by calling patient's name. This must be verified by asking or confirming with a parent or guardian the birth date of the patient.
- Select the appropriate Microtainers for the specimens to be collected. Any Microtainers containing additives should be tapped to dislodge additives from the walls and stopper.
- Position the patient.
- For Finger Sticks: The patient should be seated with his or her non-dominant arm resting comfortably on the blood-drawing chair arm support or on the bed.
- For Heel Sticks: The baby should be held by another adult if possible. Remove the baby's clothes and blanket so they will not interfere. A protective barrier should be placed under the baby. Protect the person holding the baby from possible blood contamination. If there is no one available to assist, position the baby either on their back or stomach in the center of the examination table.
NOTE: for infants up to the age of 6 months, the heel is usually the site of choice as the fingers of infants are too small for the trauma of a skin puncture.
- Select the puncture site.
- For Finger Sticks: For children and adults, use the 3rd or 4th finger of the non-dominant hand. The outer and upper region of the fingertip, halfway between the center of the fingerpad and the edge of the fingernail, is the site of choice. SEE DIAGRAM #3. One may refer to "Special Consideration" section on use of the Tenderlett
- For Heel Sticks: Avoid previous heel stick sites. The site should be on the plantar surface of the heel, beyond the lateral and medial limits of the calcareous (heel bone). The heel bone is very close to the surface of the skin at the back of the heel, and could be damaged by a puncture in this area. The puncture should NEVER be performed on the central area of the infant's foot (area of the arch). SEE DIAGRAM #4. One may refer to "Special Considerations" section on use of the Tenderfoot.
- Reassure the patient, if possible, by explaining the procedure.
- Warm the puncture site, if necessary. Use a warm, wet washcloth or chucks to warm the puncture site for at least 3 minutes. Warming the site to 42 C can increase blood flow up to sevenfold.
- Cleanse the puncture site. Use the alcohol or povidone-iodine prep to wipe the area vigorously. Allow the area to air dry or dry the skin with 2x2 gauze before the continuing. If the side is not dry, the blood will spread over the area making it difficult to collect and there is the possibility of contamination from the cleansing agent.
- Open the puncture device packaging, being careful not to contaminate the side with the cutting device.
- Perform the skin puncture.
For Finger Sticks:
For Heel Sticks:
- Exert pressure on the finger tip by holding it with your index finger and thumb. Pressure should be directed upward.
- Use the device to make a quick puncture into the site selected. Release it according to manufacturer's instructions.
- Release the finger and wait for the first drip of blood to form.
- Wipe away the first drop of blood. Avoid excessive squeezing or "milking" as tissue fluids will interfere with testing.
- Collection of Lavender microtainer should be drawn first, with other types of microtainers following. Wipe puncture site between microtainer collection to prevent cross contamination and ensure further bleeding.
- (Sartstdt) Lavender microtainers
- Be sure vent on the collection top is facing upwards.
- Place collection top at 45 degree angle to the drop of blood. Blood will flow by capillary action down the top and into the tube. Do not shake the tube as the capillary action may be lost. Fill the microtainer between the 250- and 500 ul mark. Remove collection top and replace cap. Mix gently 5-7 times.
- "Scoop" type microtainers
- Touch the top of the collector to the under surface of the drop and channel blood flow in groove of collector. Blood will flow freely through the collector and down the tube wall. When collection is complete, replace the collector with appropriate cap.
- Always try to avoid "scooping" along the skin. This method will pick up micro clots that may interfere with testing.
- Apply pressure to stop the bleeding.
- Grasp the foot firmly and puncture the selected site.
- Release the foot and allow the first drips of blood to form.
- Wipe away the first drop of blood and avoid excessive squeezing.
- Hold the foot firmly and collect the blood. The same steps can be following as in steps e and f of the finger stick procedure.
- Release the foot and allow the baby to kick from time to time as this will increase the blood flow.
- Wipe the site between specimen collections.
- When specimen collection is complete, hold gauze on the puncture site and apply mile pressure. Hold it until the bleeding stops. Do not apply tape.
- Dispose of the puncture device in the biohazardous sharps container.
- Seal or cap the tubes.
- Confirm that the patient is all right. Confirm the bleeding has stopped and the patient feels or looks normal.
- Apply direct pressure to the puncture site while bleeding continues.
- If the bleeding persists more than 5 minutes, call the physician.
Universal Precautions apply to all specimens of blood, serum, plasma, blood products, vaginal secretions, semen, cerebrospinal fluid, synovial fluid, pleural fluid, peritoneal fluid, pericardial fluid, amniotic fluid, and concentrated HIV or HBV viruses. Any specimen of any type which contains visible traces of blood should be handled using Universal Precautions.
Capillary blood samples should be processed as soon as possible after being drawn. Follow the instructions outlined in the venipuncture procedure for preparing serum, plasma, or whole blood. The following general precautions for capillary specimens should be observed:
Sources of Error
- Keep Specimen tubes capped. This should be done for safety reasons as well as specimen preservation.
- Avoid specimen agitation. Hemolysis (the breakdown of red blood cells) will occur when the specimen is agitated. A certain amount of hemolysis is unavoidable, but it would be minimal. Badly hemolyzed specimens are unacceptable for most chemistry and hematology procedures. Avoid shaking the specimen and always use gently inversion to mix specimens. Always handle specimens with care.
- Adhere to specimen time constraints. Timing is critical in most chemistry and hematology procedures. Follow manufacturer's recommendations for minimum and maximum times which specimens may be left in the tube. The time constraints on capillary specimens are more stringent then those on venous samples obtained by venipuncture.
- Refrigerate specimens not tested immediately. Anticoagulated capillary specimens should be stored at 2-8 degrees C. if they will be not bested within 4 hours. Heat may cause hemolysis.
- Abnormal fluid distribution caused by excessive squeezing.
- Anticoagulated specimens containing clots should be discarded.
- Hemolysis may be caused by excessive squeezing or alcohol left at puncture site.
- Serum/Plasma in prolonged contact with the cells will result in changes in glucose, iron, LDH, and potassium levels.