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Skin Puncture Procedure

PRINCIPLE

The skin puncture method for blood collection is used when it is impossible or impractical to obtain a venous blood sample. The following disadvantages of this technique should be considered whenever selecting this method as an option.

  • Only small volumes of sample can be obtained.
  • Physiological differences exist between venous and capillary specimens.
  • Edematous patients may contribute significant tissue fluid to the sample.
  • Excessive squeezing may cause hemolysis or introduce tissue juices into the specimen.
  • Partial clotting at the site of the wound may cause consumption of some of the cellular elements, especially platelets.

EQUIPMENT

  • Microtainer tubes - green, lavender, red or amber
  • Sterile lancets or Tenderfoot device
  • 3x3 gauze
  • Alcohol preps
  • Adhesive or expandable gauze bandages
  • Labels
  • Gloves

CAPILLARY TEST METHODS AVAILABLE

Check individual tests to determine if capillary method is acceptable or contact the supervisor of the department for additional information.

PROCEDURE

Obtain request for laboratory services with the following information.

  • Patient's full name and date of birth
  • Ordering physician's full name
  • Patient's Identification number - medical record or financial number
  • Laboratory tests ordered
  • Date requested
  • Time of collection
  • Diagnostic code or reason for testing

Reassure the patient.

  • Introduce yourself.
  • Explain the procedure.
  • Make casual conversation.

Identify the patient.

Outpatient

  • Ask the patient to state his/her full name and date of birth.
  • Verify that information with the laboratory requisition and specimen labels.
  • If the patient cannot respond, have a responsible person state the patient's full name. Document the name of the person identifying the patient.

Inpatient

  • Ask the patient to state his/her full name and date of birth.
  • Verify that information with the name and date of birth printed on the patient's hospital armband with the lab requisition and/or specimen label.
  • If the patient cannot respond, have a responsible person (parent, guardian, nurse) identify the patient.
  • If the armband is missing, notify nursing service that an armband must be placed on the patient before drawing blood.

Cautions

  • Patients having capillary specimens collected for Transfusion Services with the possibility of receiving a transfusion must be banded with a Blood Bank identification band prior to specimen collection. GettysburgHospital does not allow a capillary draw for Blood Bank specimens.
  • If the Blood Bank armband doesn't contain required information, call York Hospital Transfusion Services for instructions.
  • If the patient is missing a hospital armband, DO NOT draw a Blood Bank specimen until the hospital armband is placed on the patient by Nursing Service personnel.
  • York Hospital personnel, Laboratory personnel and limited exceptions of others, by approval of Transfusion Service supervision, are the only staff that may draw specimens for possible transfusion.
  • Blood drawn by a nurse on LTAC must be witnessed by a lab phlebotomist.
  • Verify the Blood Bank arm band has required information and patient is wearing a LTAC identification bracelet.
  • Initial tube with the Cerner identification and have the nurse write his/her name and BB armband number on the tube label.
  • When identifying a patient, do not ask "Are you Mrs. Smith?"
  • When there are any discrepancies, DO NOT collect specimen until positive identification is made.
  • Never use name cards or signs not attached to patient for identification.
  • EMR and inpatients must have a YorkHospital or Gettysburg Hospital ID armband before putting on the Blood Bank armband.

Evaluate status of patient.

Dietary considerations

  • Fasting appropriate length of time
  • Special dietary requirements.

Collection time requirements

Time of last dose for therapeutic drug monitoring

Patient position - supine vs. erect

Position the patient

Adult Patient

  • Patient seated in collection chair or wheelchair.
  • Position yourself in front of the collection chair. This protects the patient from falling forward if he/she faints and makes it easier to administer care if needed.
  • Arm rest should be locked in place. Wheelchair needs to be locked in place.
  • Position patients' arm on the armrest, with the hand in a downward position.
  • A pillow may be used for support, if needed.
  • Patient lying down.
  • Position patient's arm so it is in a downward position.
  • A pillow may be used for support, if needed.
  • Cautions
  • Have patient remove food, gum or thermometer from mouth.
  • Never perform a skin puncture while a patient is standing.

Pediatric Patient

  • Patient seated
  • Collection of blood specimens from pediatric patients presents both technical and psychological challenges.
  • Place equipment in a location that is readily accessible and out of reach of the patient.
  • A parent or caregiver may assist by holding the patient on their lap.
  • Primary phlebotomist should position themselves in front of the collection chair.
  • Have the patient position his/her arm on the armrest of the chair.

Assemble supplies.

  • Place equipment in a location that is readily accessible and out of reach of the patient.
  • Easy access to sharps container is critical.

Verify requisition and tube selection

  • Compare information on the requisition, labels and/or clipboard.
  • Verify appropriate number and types of collection containers.

Select the site

  • Adults/Children - Finger
  • The puncture is usually made on the palmar surface of the third or fourth finger of either hand.
  • Use an area on the ball of the finger that is slightly to the left or right of the center and away from the fingernail. Make the puncture across and not parallel to the whorls of the fingerprint.
  • The third and fourth finger are the preferred sites because the thumb has a pulse, the index finger may be calloused or sensitive, and the fifth finger has insufficient tissue depth to prevent bone injury.
  • Infants
  • Perform the puncture on the most medial or most lateral portion of the plantar surface of the heel.
  • Avoid a previous puncture site.
  • Punctures must never be performed on the posterior curvature of the heel, the arch of the foot, or on fingers of a newborn or infant less than one year old.

Put on gloves

  • Gloves must be worn when performing skin punctures since skin puncture causes contamination of the skin surface and poses a hazard to the laboratory worker.

Prepare the skin puncture site.

  • If foot or finger is cold, wrap in warm compress at a temperature no higher than 42┬░ for three to five minutes to warm site.
  • The infant's heel must be warmed before collecting capillary blood gases.
  • Briskly rubbing the heel or finger tip will improve circulation.
  • Cleanse the area with 70% alcohol pad.
  • Care must be taken with small infants so as not to injure the delicate skin tissue.
  • Allow alcohol to dry.

Perform the skin puncture.

  • Place the puncture device on the patient's skin and activate the release mechanism. Dispose of the puncture device in a Sharps container.
  • For infants, the heel puncture should be no deeper than 2.0 mm.
  • Wipe the first drop of blood away with dry gauze.
  • Grasp the foot or finger between the thumb and first finger and apply gentle pressure.
  • Do not milk the area or squeeze so hard that tissue is injured or bruised. If more blood is needed, begin the process again at a different site.
  • Never squeeze the wound excessively; this would contaminate the specimen with tissue juices and cause injury to an infant's delicate tissues.

Collect the specimen.

  • Collect specimen in proper microtainer for the requested testing using the correct order of draw. (Please note the change in order of draw for skin puncture specimens).
  • Lavender plug: 250-500 mL
  • Green plug: 400-600 mL
  • Red plug:<750 mL
  • Amber plug: <750 mL
  • If an anticoagulant is in the tube, mix well by gently rolling the tube between the fingers as the blood is collected.
  • When making slides, do not to touch the slide to the skin, only to the droplet of blood.
  • After blood is collected, cap the tube and gently rotate tube five times.
  • Precautions
  • Do not overfill - will cause a clotted specimen.
  • Do not underfill - will cause a contaminated specimen due to excessive anticoagulant.

Provide care to the skin puncture site.

  • After blood has been collected from an infant's heel, the foot should be elevated above the body and a clean gauze pad pressed against the puchture site until bleeding has stopped. Bandage appropriately.
  • It is not advisable to apply adhesive bandages over skin punctures on children less than two years old. Adhesive bandages can cause irritation to the infant's skin or may cause a choking hazard if it is removed.

Label the specimen.

  • Always label all tubes at the patient's side and include the required minimal information as follows:
  • For clinical lab samples, label with name, date of birth, test and collection date and time.
  • For Blood Bank samples, label with name, test, date, Blood Bank armband number, and phlebotomist's name.

Remove gloves and wash hands.

  • To remove the gloves, grasp the top and pull off carefully causing the glove to be turned inside out. The gloves may be discarded into a waste basket lined with a brown trash bag. If they are visibly contaminated with blood, they should be discarded in a red biohazard bag.

Dismiss the patient.

  • Determine that the patient is in no distress.
  • Thank the patient.
  • Replace any items that were relocated during the collection.
  • Gather all equipment and supplies.

Deliver the specimens.

Deliver the specimen to the Central Processing area of the laboratory or for YorkHospital contact Translab Services for courier pickup.

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