mlsp prelim

• Dermal Puncture


  Also known as Capillary or Skin puncture
• Dermal Puncture


  Taking a very small amount of blood from the patient, usually from the end of a finger
• Microtainer Tubes


  Small plastic tubes designed to hold approximately 600 µL of blood
• Site Selection: The pr
• To prevent contact with bone, the depth of the puncture should not exceed 2.0 mm in a device used to perform heelsticks
• Lancets


  • QuickHeel Lancet
  • BD Microtainer Contact-Activated Lancet
  • Tenderlett Lancets
  • Unistik 2 Tenderfoot Lancet
  • Feather Lancet
• Dermal puncture is the method of choice for collecting blood from infants and children younger than 2 years
• Adult patients who may require dermal puncture

  • Burned or scarred patients
  • Patients receiving chemotherapy who require frequent tests and whose veins must be reserved for therapy
  • Patients with thrombotic tendencies
  • Geriatric or other patients with very fragile veins
  • Patients with inaccessible veins
  • Obese patients
  • Patients requiring home glucose monitoring and point-of-care tests
• Phlebotomists should carefully examine the information on the requisition form to ensure that they have the appropriate equipment to collect all required samples as well as the skin puncture device that corresponds to the age of the patient
• Patient Position: For fingerstick, the patient must be seated or lying down with the hand supported on a firm surface, palm up, and fingers pointed downward. For heelstick, infants should be lying on the back with the heel in a downward position
• Capillary Puncture Steps

  1. Review and Accession the Test Request

  2. Approach, Identify and Prepare the patient

  3. Verify the Patient’s Diet Restrictions and Latex Sensitivity

  4. Sanitize Hands and put on gloves

  5. Position the Patient

  6. Select the puncture or incision site

  7. Warm the site if necessary

  8. Clean and Air-Dry the Site

  9. Prepare the equipment

  10. Puncture the site and discard the lancet

  11. The first blood drop should be wiped away because it may be contaminated with excess tissue fluid

  12. Fill and mix tubes or containers in the order of draw

  13. Place gauze and apply pressure. Keep the incision site elevated

  14. Label the specimen and observe special handling instructions

  15. Check the site and apply bandage

  16. Dispose of used and contaminated materials

  17. Thank patient, remove gloves and sanitize hands

  18. Transport specimen to the lab
• Capillary Tubes


  Small tubes used to collect approximately 50 to 75 µL of blood for the primary purpose of performing a microhematocrit test
• Primary danger in dermal puncture is accidental contact with the bone, followed by infection or inflammation
• Blood collected by dermal puncture comes from the capillaries, arterioles, and venule
• Microsample Containers

  • Capillary Tubes
  • Microtainer Tubes
• Dermal puncture is quick, requires little preparation, and reduces concern and anxiety in patients, particularly in children and nervous adults
• Patients for dermal puncture must be identified using Requisition form, Verbal identification, and ID band
• Lancets


  Sterile, disposable, sharp-pointed or bladed instrument that punctures or cuts skin to obtain capillary blood specimen
• Warming the site increases blood flow as much as 7 times
• Warming the Site


  1. Primarily required for:

  2. Patients with very cold or cyanotic fingers

  3. For heelsticks to collect multiple samples

  4. For the collection of capillary blood gases

  5. Moistening a towel with warm water (42°C) or activating a commercial heel warmer and covering the site for 3 to 5 minutes
• Patient Position for fingerstick


  Seated or lying down with the hand supported on a firm surface, palm up, and fingers pointed downward
• Capillary Blood Gases

  1. Arterial blood preferred for blood gases and pH levels in adults

  2. Collection in heparinized blood gas pipettes

  3. Pipette should fill in less than 30 seconds
• Puncture Device Disposal


  Placing the puncture device in an appropriate sharps container
• Order of draw

  1. Capillary blood gas specimens (CBGs)

  2. EDTA specimens

  3. Other additive specimens

  4. Serum specimens
• Bandaging the Patient


  Applying pressure to the puncture site with sterile gauze
• Labeling the Sample

  Microsamples must be labeled with the same information required for venipuncture samples
• Completion of the Procedure

  1. Proper waste disposal of all used materials

  2. Proper Handwashing

  3. Thanking the patient and/or the parents for their cooperation
• Special Dermal Puncture for Collection of Newborn Bilirubin

  1. Bilirubin is light-sensitive and must be protected from light during and after collection

  2. Use of amber-colored Microtainer for neonatal bilirubin collection
• Cleansing the Site

  Using 70% isopropyl alcohol in a circular motion
• Newborn Screening

  1. Testing for as many as 29 metabolic disorders

  2. Importance of early detection of defects

  3. Testing for genetic, metabolic, hormonal, and functional disorders in newborn babies

  4. Elevated substance levels in blood compared to urine

  5. Use of tandem mass spectrophotometry for screening

  6. Blood collection by heelstick and placement on filter paper
• Patient Position for heelstick

  Infants lying on the back with the heel in a downward position
• Site Selection

  1. Primary dermal puncture sites:

  2. Plantar surface of the heel - infants younger than 1 year old

  3. 3rd and 4th fingers on the palmar side of the nondominant hand - performed on adults and children over 1 year of age

  4. Areas not to be punctured: Callused, scarred, bruised, edematous, cold or cyanotic, or infected areas
• Order of Collection

  1. Capillary blood gases

  2. Blood smear

  3. EDTA tubes

  4. Other anticoagulated tubes

  5. Serum tubes
• Performing the Puncture


  Supporting the heel or finger well, holding firmly without squeezing the puncture area. Massaging the area before the puncture may increase blood flow
• Sample Collection

  1. Wiping away the first drop of blood with a clean gauze

  2. Alternately applying pressure to the area and releasing it to produce satisfactory blood flow
• Dermal puncture identification

  1. Using Requisition form

  2. Verbal identification

  3. ID band
• Tourniquet


  • Constricting device applied to a patient’s arm prior to venipuncture with the aim of inflating the veins by restricting venous blood for a period of time
• Methods of venipuncture

  • Syringe
  • Evacuated Tube System
  • Butterfly
• It is important to select the right gauge of the needle based on the age of the patient, amount of blood, and type of sample
• Evacuated Tube System


  • Blood is collected directly into the evacuated tube, eliminating the need for transfer of specimens and minimizing the risk of biohazard exposure