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This Guideline is applicable to all medical and nursing staff working in neonatal units in The West of Scotland.
A capillary sample is a blood sample collected by pricking the skin. Capillaries are tiny blood vessels which are near the skin surface.
In the neonate it is generally performed by heel puncture/stick. This is a minimally invasive and easily accessible method of obtaining capillary blood samples for a variety of tests. Heel puncture/stick sampling can also help preserve venous access for future intravenous lines.
Capillary sampling can be used to take small volume specimens for monitoring:
Good technique is important to avoid the following problems
NB – Consideration should be given to repeating a specimen, possibly using a venous sample, if the result is out of keeping with the baby’s condition or previous results.
Morbidity for the baby
Prior to carrying out any procedure on a baby the practitioner must be familiar with the infant’s plan of care. In order to provide developmentally supportive care an effort should be made to cluster any blood samples required as well as trying to time the sampling with the baby’s cares as far a possible.
Check patient ID
Ensure positive identification of baby and that name bands, blood forms and bottles all correlate. Double check Chi number in case of twins to ensure right test, for right baby and labelled appropriately.
If required, consent should be sought from parents prior to the procedure being carried out e.g. Newborn bloodspot screening.
Ensure a Safe Environment.
Ensure the baby is appropriately positioned/contained/swaddled.
Whenever possible, involve the mother in the procedure, using skin to skin contact, breastfeeding or non-nutritive sucking. For some procedures oral sucrose may be used – see oral sucrose guideline.
Identifying an appropriate site
The shaded areas on the lateral aspects of the heel are the preferred sites as this avoids the main nerves.The area should be examined for previous, recent, puncture sites and the chosen site rotated if frequent sampling is required.
Procedure for obtaining the sample
This is not a sterile procedure however a clinical hand wash should be performed or alcohol gel applied (See antisepsis guidelines) before donning gloves.
To obtain the blood sample:
Completing the Procedure
Once the sample has been obtained:
Blumenfeld TA, Turi GK, Blanc WA (1979) Recommended site and depth of newborn heel skin punctures based on anatomical measurements and histopathology. Lancet 1 (8110): 230-3.
Mancini AJ (2004) Skin. Pediatrics 113 (4 Suppl): 1114-9.
McIntosh N, Van Veen L, Brameyer H (1993) The pain of heel prick and its measurement in preterm infants. Pain 52 (1): 71-4.
Royal College of Nursing (2005) Competencies: an education and training competency framework for capillary blood sampling and venepuncture in children and young people. London, RCN
Royal College of Nursing (2010) Restrictive physical intervention and therapeutic holding for children and young people. London, RCN
Wallymahmed M (2007) Capillary blood glucose monitoring. Nursing Standard 21,38: 35-38
Last reviewed: 16 September 2019
Next review: 01 September 2022
Author(s): L. Raeside - ANNP RHC
Co-Author(s): Other Professionals Consulted: Dr J Simpson - Neonatal Consultant RHC; Dr L. Jackson - Neonatal Consultant RHC
Approved By: West of Scotland Neonatology Managed Clinical Network