100 Section III ■ Blood Sampling

samples from larger infants who require frequent

point-of-care glucose testing (8).

c. Nonautomated (manual) stylet-type lancets and

spring-loaded needle-puncture devices designed for

adult glucose testing are not appropriate for infants (7).

2. Heel warmer: Chemically activated packet to heat

heel prior to capillary testing. If heel warming is used, a

commercial prepackaged unit provides controlled temperature. The warmer should be applied for 5 minutes

and then removed prior to heelstick.

H. Precautions

1. Site

a. Do not use the end of the heel. The calcaneum is

superficial at this site, and there is an increased risk

of osteomyelitis (2).

b. Do not use fingertips, toes, or earlobes of babies.

2. Hand position

Do not squeeze the heel. Squeezing the heel results in

greater pain, lower blood yield, and increased cell

lysis.

3. Collection

a. If using capillary tubes for blood transfer, it is essential to determine whether the tube contains substances such as anticoagulants, which may have the

potential to interfere with lab results. Do not use

tubes containing anticoagulants for newborn metabolic screens.

b. Scoop-shaped collectors provided with mini–lab

tubes are used to guide blood drops to the specimen

tube. Avoid repeated “scooping” along the surface

of the foot. Microclots that form in blood on the

skin can alter lab results.

I. Technique

1. Identify site; the preferred areas for capillary heel testing are the outer aspects of the heel (Fig. 16.1).

a. Vary sites to prevent bruising and skin damage.

b. The plantar surface can be used in term and late

preterm term infants if the preferred areas are compromised by previous frequent testing (Fig. 16.2).

The skin-to-calcaneal perichondrium distance is at

least 3 mm in most term babies and in 91% of babies

at 33 to 37 weeks’ gestation, but is at least 3 mm in

only about 60% of babies <33 weeks’ gestation (2).

2. Apply heel warmer or warm towel for 5 minutes.

Remove just before procedure.

3. Provide comfort measures: Facilitated tucking/swaddling

and the use of pacifiers combined with administration of

a concentrated sucrose solution results in less measurable pain and faster resolution of discomfort in the infant

following the procedure (9,10) (Fig. 4.1). Kangaroo

Care 30 minutes prior to and during procedure has

shown a reduction in pain scores for stable premature

infants; however, the long-term association of maternal

contact during painful stimulus has not been studied.

(11,12)

4. Wash hands and put gloves on.

5. Cleanse site with Betadine followed with saline wipe or

alcohol wipe.

6. Position hand with fingers along the calf and thumb at

ball of foot to stabilize. Apply pressure along calf toward

heel (Fig. 16.3).

7. Prepare automated device by removing release clip.

8. Place automated device on site and activate.

9. Apply pressure to leg with counterpressure to ball of

foot and allow blood drop to form.

10. Wipe away first drop of blood with gauze or clean wipe.

11. Using capillary action, fill blood gas tube, holding tube

horizontally (Fig. 16.4).

Infant Size Available Products Incision Depth/Length

<1,000 g Tenderfoot Micro-preemie 0.65 mm/1.40 mm

Low-birthweight and preemie >1,000 g Tenderfoot Preemie/BD Quickheel Preemie 0.85 mm/1.75 mm

Term to 3–6 mo Tenderfoot Newborn/BD Quickheel Infant 1.0 mm/2.50 mm

6 mo–2 y Tenderfoot Toddler 2.0 mm/3.00 mm

Table 16.1 Examples of Automated Heel-Lancing Products Based on

Infant Size

Fig. 16.1. Appropriate sites for capillary heelstick sampling are

along the sides of the heels.