Chapter 16 ■ Capillary Blood Sampling 101

J. Specimen Handling

1. Collect blood gas sample first, then hematology samples, and then chemistry/toxicology samples.

2. Ensure that blood gas samples are free of air bubbles.

a. Place the tube horizontally so that the blood is drawn

by capillary action and does not collect air bubbles

that can alter results. Apply caps to ends of tube.

b. Capillary blood gas samples should be analyzed

within 10 minutes or should be kept horizontally on

ice for up to 1 hour, and the tube must be rolled

prior to analysis. Consult institution laboratory for

guidance on blood gas sample storage and transport.

3. Flick side of hematology microtube during collection

process to activate anticoagulant and prevent clotting.

4. Newborn metabolic screen: Specific collection guidelines (13)

a. Minimum 24 to 48 hours after birth

b. Integrity of collection medium: Avoid touching filter paper, as oils from finger can compromise results.

c. Single (no overlapping) drops on filter paper.

Position infant so that incision is in the dependent

position, allowing a large drop of blood to form.

Blood should drop freely onto designated circle on

filter paper. Repeat for each circle.

d. Do not apply blood using capillary tubes that contain anticoagulants or other materials that can interfere with lab results.

K. Complications

1. Pain

2. Infection (cellulitis, abscess, perichondritis, osteomyelitis) (Fig. 16.5) (14,15)

3. Tissue loss and scarring

4. Calcified nodules (16)

Fig. 16.2. Alternative site for capillary heelstick sampling. If frequent sampling has rendered the sides of the heels unsuitable, the

plantar surface between them can be used. Do not incise the end

of the heel.

Fig. 16.3. Position for hand and automated lancing device.

Position heel in the apex of the angle of the thumb and forefinger

with fingers along the calf and thumb along the ball of the foot.

Place automated lancing device in appropriate position. Apply

pressure along the calf with counterpressure by the thumb. Do not

squeeze the heel.

Fig. 16.4. Capillary blood gas sampling.

12. Release pressure, allowing capillaries to refill.

13. Guide blood drops into tube or collect with capillary

tube for transfer to laboratory tube.

14. If blood stops flowing, wipe site to remove clot with

alcohol swab, gauze, or clean wipe; ensure time for

capillary refill; and then reapply pressure to leg. If

blood does not flow, choose another site and repeat procedure or consider venipuncture.

15. When samples have been collected, apply pressure to

puncture site and wrap with gauze or apply adhesive

bandage.

16. Continue comfort measures.

102 Section III ■ Blood Sampling

L. Inaccurate Laboratory Results

1. Hyperkalemia secondary to excessive hemolysis

a. Use proper technique and procedures to minimize

cell lysis.

2. Erroneous blood gas results

a. Ensure that sample is free of air bubbles.

b. Avoid delay in analysis.

c. Use proper technique and procedures to minimize

cell lysis.

References

1. Johnson K, Cress G, Connolly N, et al. Neonatal laboratory blood

sampling: comparison of results from arterial catheters with those

from an automated capillary device. Neonatal Network. 2000;

19(1):27.

2. Arena J, Emparanza J, Nogues A, et al. Skin to calcaneus distance

in the neonate. Arch Dis Child Fetal Neonatal Ed. 2005;90(4):F328.

3. Vertanen H, Fellman V, Brommels M, et al. An automated incision device for obtaining blood samples from the heels of preterm

infants causes less damage than a conventional manual lancet.

Arch Dis Child Fetal Neonatal Ed. 2001;84(1):F53.

4. Shepherd AJ, Glenesk A, Niven CA, et al. A Scottish study of

heel-prick blood sampling in newborn babies. Midwifery. 2005;

7(2):158.

5. Kellan B, Waller J, McLaurin C, et al. Tenderfoot preemie vs a

manual lancet: a clinical evaluation. Neonatal Network. 2001;

20(7):31.

6. Kazmierczak SC, Robertson AF, Briley KP. Comparison of hemolysis in blood samples collected using an automatic incision device

and a manual lancet. Arch Pediatr Adolesc Med. 2002;156(11):1072.

7. Shah V, Taddio A, Kulasekaran K, et al. Evaluation of a new lancet

device (BD QuickHeel) on pain response and success of procedure

in term neonates. Arch Pediatr Adolesc Med. 2003;157(11):1075.

8. Noerr B. State of the science: neonatal hypoglycemia. Adv

Neonatal Care. 2001;1(1):4.

9. Gibbins S, Stevens B. The influence of gestational age on the efficacy and short-term safety of sucrose for procedural pain relief.

Adv Neonatal Care. 2003;3(5):241.

10. Coleman M, Solarin K, Smith C. Assessment and management of

pain and distress in the neonate. Adv Neonatal Care. 2002;

2(3):123.

11. Cong X, Ludington-Hoe SM, McCain G, et al. Kangaroo care

modifies preterm infant heart rate variability in response to heel

stick pain: pilot study. Early Human Dev. 2009;85(9):561.

12. Ludington-Hoe SM, Hosseini R, Torowicz DL. Skin-to-skin contact (Kangaroo Care) analgesia for preterm infant heel stick.

AACN Clin Issues. 2005;16(3):373.

13. Bryant K, Horns K, Longo N, et al. A primer on newborn screening. Adv Neonatal Care. 2004;4(5):306.

14. Abril Martin JC, Aguilar Rodriguez L, Albinana Cilvetti J. Flatfoot

and calcaneal deformity secondary to osteomyelitis after heel

puncture. J Pediatr Orthop. 1999;8:122.

15. Lauer BA, Altenburgher KM. Outbreak of staphylococcal infections following heel puncture for blood sampling. Am J Dis Child.

1981;135:277.

16. Williamson D, Holt PJ. Calcified cutaneous nodules on the heels

of children: a complication of heelsticks as a neonate. Pediatr

Dermatol. 2001;18:138.

Fig. 16.5. Cellulitis of heel—complication of capillary heelstick sampling.