Blood Drawing From Peripheral Sites: Heel Stick and Finger Stick

CLINICAL GUIDELINES

Blood sampling is obtained upon a healthcare prescriber’s order using aseptic technique and standard precautions.
Blood sampling is completed by a registered nurse (RN), licensed practical nurse (LPN), healthcare prescriber, or appropriately certified technician.
Unlicensed assistive personnel (UAPs) may perform blood drawing as delegated by the RN, upon completion of a competency program and consistent with their job description.
Consider venipuncture for blood specimen collection because it is less painful; otherwise, use the following:
- Heel stick in infants up to 18 months of age.
- Finger stick in children over 18 months of age who require a specimen of less than 2.5 mL.

CHILD AND FAMILY ASSESSMENT AND PREPARATION

Assess child for signs of poor perfusion, local edema, infection at the site, and impaired blood coagulation. The presence of these findings can lead to inadequate sampling, blood specimen contamination, increased pain, and infection. Avoid edematous areas because the presence of the fluids can contaminate the blood specimen. The presence of ecchymosis or hemolyzed samples can give false results (e.g., elevated bilirubin or potassium levels). Rotate the sites of puncture to decrease these complications.
To decrease procedural pain, apply topical anesthetic (e.g., lidocaine, prilocaine), or mechanical device (e.g., Buzzy Pain Relief System) for finger stick before procedure, as time allows, and based on child’s preference. The research is conflicting, but most studies indicate that topical anesthetics are not effective for the pain of heel stick. Because a risk for methemoglobinemia exists, do not use lidocaine and prilocaine if the child is receiving methemoglobin-inducing agents (e.g., sulfonamides, acetaminophen).
Question the family about the existence of coagulation disorders in their family history and previous signs of a blood dyscrasia (e.g., the presence of unexpected ecchymotic spots or prolonged bleeding after blood testing or injury).
Administer vitamin K per newborn routine before heel stick to increase clotting and prevent prolonged bleeding.
Verify healthcare prescriber’s order for laboratory tests.
Explain procedure to child, as appropriate, and family caregivers.
Prepare the child, as appropriate, to cognitive and developmental level (see Chapter 2). Provide therapeutic play as indicated, or involve a child life specialist, to allow the child to work through fears, help with the procedure (e.g., hold Band-Aid), and master control of the situation.
Encourage a family member to remain with the child during the procedure. Discuss with the family member comfort measures and holding techniques (e.g., swaddling, skin-to-skin contact, breastfeeding, use of sucrose pacifiers, sweet tasting solutions) and distraction techniques (e.g., audiovisual) that they can use with their child. Select measures to employ and initiate use of these measures prior to beginning the procedure (see Chapter 7).

PROCEDURE
Performing Heel and Finger Sticks

Steps	Rationale/Points of Emphasis
1 Gather the necessary supplies, including puncture device. An automated device is recommended; refer to manufacturer’s recommendations for use.	Promotes efficient time management and provides an organized approach to the procedure. Mechanical devices either puncture or incise the skin and may be less painful than lancets. A shallow incision may facilitate bleeding, healing, and reduce pain. There is an increased chance of bone penetration resulting in injury and infection (e.g., perichondritis, osteomyelitis) with puncture devices of longer length. Research on preterm infants indicates that the use of an automatic incision device for collecting repeated skin puncture samples is less traumatic than the use of a conventional manual lancet, causing less bruising and inflammation of the heel.
	caREminder
	Manual lancets for pediatric patients should be no longer than 1.5 mm.
2 Apply warming device to area for 5-10 minutes before puncture. The following methods are acceptable: • Commercially prepared chemical warmer • Warm cloth (<109°F or 42.8°C)	Increases blood flow and reduces hemolysis and bruising. Hematocrit and capillary blood gas samples collected from nonwarmed heels are inaccurate. Do not use microwave-warmed products because uneven heating occurs and presents a burn risk. Research on heel warming before capillary blood sampling for other uses than blood gas sampling, indicates that this may be an unnecessary technique. Volume of blood, collection time, crying time, and repeat procedures have not indicated they were enhanced by prewarming the site. More research is needed.
3 Perform hand hygiene and don gloves.	Standard precaution to reduce transmission of microorganisms.
4 Remove warming device.	Leaving a warming device in contact with the skin cools by conduction.
5 Select and identify puncture site: Heel, outer aspects (infants younger than 18 months) Lateral to an imaginary line drawn from between the fourth and fifth toes and running parallel to the lateral aspect of heel (Figure 17-1) Figure 17-1 Sites for capillary blood specimens Medial to an imaginary line drawn from the middle of the great toe and running parallel to the medial aspect of the heel. Never puncture the back of an infant’s heel because the calcaneus is closest to the surface in that location.	Using appropriate site minimizes the risk for injury (e.g., striking artery, bone, or nerve).
	caREminder
	Avoid calluses, scars, and lesions. These areas will be difficult to penetrate with the lancet.
Repeated heel sticks in the same anatomical area should be made 2 mm apart. Avoids puncturing through a previous puncture site that might be infected; reduces chance of cellulites.
Finger (older than 18 months of age) The side of the third or fourth finger, near the tip (Figure 17-1)
6a Cleanse puncture site with antiseptic wipe and allow to dry for 30 seconds. Then dry with sterile gauze.	Provides disinfection. Drying of site prevents alcohol contamination of blood sample, which may cause hemolysis and errors in glucose values.
6b If topical anesthetic cream has been used, remove before cleansing.	Residual alcohol may cause hemolysis and errors in glucose values.
7 Place extremity in a dependent position. Grasp extremity firmly.	Facilitates blood flow to area. Prevents inadvertent movement by child; controls position of site for puncture.
For heel stick, apply mild pressure between thumb and fingers to hold ankle in dorsiflexion. Do not excessively squeeze the heel.
8 Briskly puncture skin with selected lancing device or if using a lancing device, place the lancing device on the outer portion of plantar surface of heel or on the tip of the finger. Trigger the device following manufacturer’s instructions.	Quick puncture with the lancet causes less pain.
Wipe away first drop of blood with sterile gauze.	Eliminates tissue fluids or residual alcohol potentially present in initial drop of blood, which can alter test values.
9a Continue to hold puncture site in dependent position while gently applying intermittent pressure to surrounding area; collect blood in appropriate container.	Harshly squeezing the area may produce hemolyzed samples, cause pain and bruising and may contaminate sample with tissue fluid.
9b Obtain blood gases first. Place blood gas sample on ice if analysis will be delayed more than 10 minutes.	Holding tube horizontal and applying intermittent pressure facilitates blood flow.
9c When using capillary tubes or micropipettes, hold horizontally to fill them by capillary action and fill two thirds to three fourths full. Cover the end with your finger when transferring the specimen to test strip, sealing clay, or other material. See Chapter 77 for a reviewing of blood collection techniques for newborn screening tests.	Air bubbles may cause inaccurate blood gas results. caREminder
	Do not pipette orally or scrape blood into tubing. Oral pipetting greatly increases the chance of contact with potentially contaminated body fluids and scraping causes hemolysis.
9d When using multiple microtainers, specimens should be collected in the following order: • Ethylenediaminetetraacetic acid tubes (purple and green top tubes) • Tubes with additives (blue top tubes) • Serum tubes (yellow and red top tubes)	Covering the tube prevents blood loss.
10a Elevate extremity above level of heart. Gently press dry sterile gauze to puncture site until bleeding stops.	Facilitates hemostasis.
10b Do not use bandages.	Bandages can lead to skin maceration and pose an aspiration hazard.
11 Properly dispose of contaminated equipment. Place lancing device in sharps container and bloodsoaked gauze in a biohazard bag.	Prevents needlestick injury and transmission of blood-borne pathogens.
12 Remove gloves and perform hand hygiene.	Reduces transmission of microorganisms. Standard precautions.
13 Perform point-of-care testing or label specimen with child’s name, medical record number and unit, date and time of collection, and collector’s initials.	Ensures that correct specimen is tested for the right patient. Inaccurate results may be due to hemolysis causing hyperkalemia, air bubbles causing erroneous blood gas results, or platelet clumping.
14a Place specimen in biohazard bag and transport specimen to laboratory, if necessary.	Standard precautions.
14b Provide appropriate environment for transport (e.g., ice, refrigeration).	Reduces degradation of specimen before analysis.